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ツクシガイ科 Family Costellariidaeの写真図鑑

 投稿者:  投稿日:2018年 5月22日(火)12時28分6秒 pdadd2aa5.tokynt01.ap.so-net.ne.jp
  ツクシガイ科 Family Costellariidaeの写真図鑑
http://www.kiichmaja.com/tukusigai/tukusigai.html
 

高知大のスズメバチ無力化スプレーの話

 投稿者:  投稿日:2018年 4月 2日(月)01時56分42秒 KD182250243003.au-net.ne.jp
  応動昆で高知大のスズメバチ無力化スプレーの話を聞いてきた。スズメバチはボクトウガ由来の成分を嫌い、実際にボクトウガが樹液の滲出を促進させた餌場は放棄するらしい。高知大のグループでは既にこの成分を使ったスズメバチ無力化スプレーの製品化を行っており、4月中には販売予定だそう。
https://twitter.com/102mutilla8274/status/979338041335496706?s=11

ボクトウガ由来の成分をスズメバチが忌避する理由は不明。大型の捕食者ボクトウガはスズメバチにも危険な存在なのか、単にスズメバチ忌避成分をボクトウガが利用しているだけか。実際、スズメバチは樹液を占有し他の昆虫を追い払ってしまうのでボクトウガにとってスズメバチが邪魔な存在なのかも。

忌避剤を吹きかけられたスズメバチはものすごくこれを嫌がり、半狂乱になりながら地面を転げまわるが、しばらくすると放心したように巣に戻っていくらしい。実際見せていただいた動画では、尋常ではない嫌がり方をしていた。駆除業者だけでなく、養蜂家が自分の巣箱を守る目的でも使える可能性がある。

スズメバチの仲間はコロニーに近づく外敵に対して、まず警告音を出して威嚇を行います。うちのU先生のHPで実際の警告音を聞けます。
http://www.agr.kyushu-u.ac.jp/lab/ine/ueno/wasp2.html
注意していないと羽音の音でかき消されそうですが、この音が聞こえたらスプレーを用意して無力化するという戦術でいけば良いと思います。
 

ノグチゲラの巣の入ったG地区、H地区の生息分布図

 投稿者:  投稿日:2018年 3月30日(金)21時29分11秒 KD182250243006.au-net.ne.jp
  伊波 洋一 (いは よういち)? @ihayoichi

https://twitter.com/ihayoichi/status/979615219117797376
下の左図は、ノグチゲラの巣の入ったG地区、H地区の生息分布図にヘリパッドの位置を図示した図面。右は、昨年まとめた、高江オスプレイパッド建設問題の国政活動報告書。下記のURLでダウンロードできます。
http://ihayoichi.jp/yoichi_wp/wp-content/uploads/2018/03/houkoku_Vol01.pdf
 

Aristea inaequalis

 投稿者:  投稿日:2018年 3月19日(月)23時48分44秒 KD182250243002.au-net.ne.jp
  http://www.anniesannuals.com/plants/view/?id=1851
Indestructible and blue!I recommend this South African Iris relative to beginning gardeners more often than any other plant as its CLAY, HEAT and DROUGHT TOLERANT and deer resistant! Blooming Spring thru Fall with quite lovely 1.25” starry blue flowers well displayed on branching 2’ spikes. Handsome ever-blue strappy leaves form a tidy 3’x3’ clump that never needs cutting back. Each year it seems to bloom even more!
 

宇宙滞在で遺伝子が変化、一卵性双生児と一致せず NASA

 投稿者:  投稿日:2018年 3月15日(木)21時26分18秒 KD182250243015.au-net.ne.jp
  宇宙滞在で遺伝子が変化、一卵性双生児と一致せず NASA
https://www.cnn.co.jp/fringe/35116194.html

(CNN) 宇宙に1年間滞在した宇宙飛行士は、身体の外見だけでなく、遺伝子にも変化が起きているという研究結果が、米航空宇宙局(NASA)の双子研究の一環として発表された。

この調査では、国際宇宙ステーション(ISS)に1年間滞在したスコット・ケリー宇宙飛行士の遺伝子のうち、7%は地球に帰還してから2年たった後も、正常な状態に戻っていないことが分かった。

研究チームは、ISS滞在中と帰還後のケリー氏の身体の変化を、地上にいた一卵性双生児のマーク氏と比較。その結果、以前は一致していた2人の遺伝子が、宇宙滞在後は一致しなくなっていたという。

スコット氏の遺伝子の7%の変化は、少なくとも5つの生物学的経路や機能に関連する遺伝子が変化したことをうかがわせる。

今回の研究結果は、NASAが進める人体研究プロジェクトのワークショップで1月に発表された。

研究チームは宇宙滞在によって起きる身体的変化を調べるため、スコット氏の代謝産物(生命の維持に必要)、サイトカイン(免疫細胞によって分泌)、たんぱく質(各細胞内の活力)について、宇宙滞在前と滞在中、帰還後に測定を行った。

その結果、宇宙滞在は酸欠によるストレス、炎症の増加、劇的な栄養の変化をもたらし、遺伝子発現に影響を及ぼしていることが分かった。

スコット氏の遺伝子発現は、地球に帰還すると93%が正常に戻ったが、残る数百の「宇宙遺伝子」は変異したままだった。その一部は宇宙滞在のストレスによって変異したと思われる。

スコット氏の細胞では、酸欠と高濃度の二酸化炭素が原因と思われる低酸素症が起きていた。また、「細胞の発電所」と呼ばれるミトコンドリアにも損傷の形跡があった。

老化の程度を表す染色体末端部位のテロメアにも変化が見られた。宇宙滞在中はテロメアの長さの平均値が大幅に伸びたが、地球に戻ると約48時間以内に、出発前に近い値に戻って落ち着いた。

そうしたテロメアの変化やDNAの損傷と修復は、放射線とカロリー制限によって引き起こされたと研究チームは推定する。

ほかにもスコット氏のコラーゲンや血液凝固、骨形成にも、体液移動や無重力の影響と思われる変化が起きていた。免疫が異常に活性化する現象も確認され、極端な環境の変化によるものと研究チームは推定している。

NASAが計画している火星の有人探査は3年間のミッションになる。ケリー氏が経験した1年間の宇宙滞在は、この計画に向けた科学的な足掛かりとなる。
 

「森友」文書書き換え 財務省の調査結果 全文書掲載

 投稿者:  投稿日:2018年 3月13日(火)05時47分4秒 KD182250243015.au-net.ne.jp
  NHKが全文公開しました。
「森友」文書書き換え 財務省の調査結果 全文書掲載
全78ページPDFがダウンロードできます。
https://www3.nhk.or.jp/news/special/moritomo_kakikae/
 

首都圏「西友」で販売へ 湯川産コシヒカリ

 投稿者:  投稿日:2018年 3月 9日(金)03時35分59秒 KD182250243001.au-net.ne.jp
  10万Bq/m2の猛烈な汚染地域のコシヒカリを首都圏「西友」で販売へ

Clara Brahms @ClaraBrahms
https://twitter.com/ClaraBrahms/status/949221742756573185
湯川村は10万Bq/m2の猛烈な汚染地域ですよ?

首都圏「西友」で販売へ 湯川産コシヒカリ
http://www.minpo.jp/pub/topics/jishin2011/2018/01/post_15694.html
 JA会津よつばは、今月中旬から湯川産コシヒカリを首都圏の大手スーパー「西友」の店頭で販売する。東京電力福島第一原発事故発生後に首都圏で会津産米の取扱店が新たに決まるのは初めてで、本県農産物への風評払拭(ふっしょく)が期待される。
 取扱量は5000俵(300トン)で、同JAが湯川村のふるさと納税の返礼用として年間で確保している1万2000俵の一部を活用する。コメは5キロ単位で販売し、米袋のデザインは県の協力で「ふくしまプライド。」の文字とロゴマークを入れた。同JAと県は発売に合わせてキャンペーンを展開する。
 JAが取り扱う会津産米は首都圏のスーパーなどで新潟県の魚沼産コシヒカリと並ぶ人気を誇っていたが、原発事故後は取引を継続した数件を除いて店頭から姿を消していた。大手コンビニエンスストアのおにぎりなど業務用米としての評価は高まっていたが、首都圏などの一般消費者向けの商品棚に陳列することはほとんどなかった。
 JA会津よつばの五十嵐克博米穀課長は「湯川産米の販売を機に一般消費者にも会津のコメのおいしさを再評価してほしい」と期待を込める。県農産物流通課は「取引が継続されることで県産品の価格上昇や販売促進につながってほしい」としている。

(2018/01/05 12:07カテゴリー:福島第一原発事故)
 

八重山離島採集観察地ガイド

 投稿者:  投稿日:2018年 3月 5日(月)14時56分54秒 KD182250243018.au-net.ne.jp
  八重山離島採集観察地ガイド
青木一宰 編著, 2018.
A5, 36pp.(フルカラー), 3,000円
http://kawamo.co.jp/roppon-ashi/sub749.htm
八重山の離島に生息している蝶の採集・観察地に関してのポイントマップです。
マップは全10葉(西表島4、波照間島2、黒島1、小浜島1、与那国島2)、紹介するポイントは全24地点となっています。
各エリアごとに詳細地図が載っており、目印となるポイントや食草のある場所が地図上にプロットされていて、分かりやすい構成となっています。
ポイント周辺のオススメ食堂にも触れられており、八重山在住の著者ならではの情報が満載です。
八重山諸島島嶼別蝶類分布表(改訂版)付。
※目次、内容見本、ともに制作中のもののため、若干の変更が見込まれます。



目次
はじめに……………………………………………………………………………2
目次…………………………………………………………………………………3
八重山諸島概略……………………………………………………………………4
西表島概略…………………………………………………………………………6
●大富遊歩道………………………………………………………………………8
●高那………………………………………………………………………………10
●浦内………………………………………………………………………………12
●祖納・白浜………………………………………………………………………14
●小浜島……………………………………………………………………………16
●黒島………………………………………………………………………………18
波照間島概略………………………………………………………………………20
●毛原………………………………………………………………………………22
●慶原………………………………………………………………………………24
与那国島概略………………………………………………………………………26
●宇良部岳~新川線………………………………………………………………28
●与那国嵩農道~満田原林道……………………………………………………30
八重山諸島島嶼別蝶類分布表……………………………………………………32
 

8000ベクレルの生コンかよ

 投稿者:  投稿日:2018年 3月 5日(月)14時35分35秒 KD182250243018.au-net.ne.jp
  福島の生コン工場完成 復興事業に供給 下越仙台陸送
http://www.kahoku.co.jp/tohokunews/201802/20180227_63034.html
 建設資材商社の下越物産(仙台市)の子会社、下越仙台陸送(同)が福島県広野町の広野工業団地に建設していた生コンクリート工場が完成し、完工式が26日、現地であった。地元の双葉地方で進む東日本大震災の復興関連事業などに生コンを供給する。
 敷地は約8400平方メートル。震災や東京電力福島第1原発事故の後に撤退した食品工場の跡地を再整備した町から賃借した。同社によると、当面は年間約6万立方メートルを出荷し、将来は10万立方メートル程度への引き上げを目指す。従業員は15人体制で今後増やす予定。
 常磐自動車道の4車線化や原発事故対応など周辺のインフラ整備に伴う需要を想定。相沢勇栄社長は完工式で「安定的に高品質な生コンを提供するのは復興を目指す地域における私たちの責務だ」と話した。
 

論文:東京湾の放射性セシウム汚染(近大ほか)Published: March 1, 2018

 投稿者:  投稿日:2018年 3月 3日(土)21時36分24秒 KD182250243012.au-net.ne.jp
  sinwanohate・レイジ@sinwanohate
https://twitter.com/sinwanohate/status/969579812359618568
論文:東京湾の放射性セシウム汚染(近大ほか)
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0193414
福島並みに汚染した首都圏北部から江戸川などの流れに乗って東京湾の河口に蓄積。セシウムは土壌粒子として運ばれ、河口付近で蓄積しているため、湾内全体には拡散しない。東京湾の放射能汚染の長期的な調査が必要、と警告。

以下抜粋
Spatiotemporal distribution and fluctuation of radiocesium in Tokyo Bay in the five years following the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident
Hideo Yamazaki, Masanobu Ishida , Ryoichi Hinokio, Yosuke Alexandre Yamashiki, Ryokei Azuma
Published: March 1, 2018 https://doi.org/10.1371/journal.pone.0193414
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0193414

Abstract

A monitoring survey was conducted from August 2011 to July 2016 of the spatiotemporal distribution in the 400 km2 area of the northern part of Tokyo Bay and in rivers flowing into it of radiocesium released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. The average inventory in the river mouth (10 km2) was 131 kBq?m-2 and 0.73 kBq?m-2 in the central bay (330 km2) as the decay corrected value on March 16, 2011. Most of the radiocesium that flowed into Tokyo Bay originated in the northeastern section of the Tokyo metropolitan area, where the highest precipitation zone of 137Cs in soil was almost the same level as that in Fukushima City, then flowed into and was deposited in the Old-Edogawa River estuary, deep in Tokyo Bay. The highest precipitation of radiocesium measured in the high contaminated zone was 460 kBq?m-2. The inventory in sediment off the estuary of Old-Edogawa was 20.1 kBq?m-2 in August 2011 immediately after the accident, but it increased to 104 kBq?m-2 in July 2016. However, the radiocesium diffused minimally in sediments in the central area of Tokyo Bay in the five years following the FDNPP accident. The flux of radiocesium off the estuary decreased slightly immediately after the accident and conformed almost exactly to the values predicted based on its radioactive decay. Contrarily, the inventory of radiocesium in the sediment has increased. It was estimated that of the 8.33 TBq precipitated from the atmosphere in the catchment regions of the rivers Edogawa and Old-Edogawa, 1.31 TBq migrated through rivers and was deposited in the sediments of the Old-Edogawa estuary by July 2016. Currently, 0.25 TBq?yr-1 of radiocesium continues to flow into the deep parts of Tokyo Bay.


Introduction

Tokyo Bay is a closed bay that extends 70 km from north to south and 20 km from east to west, covers a total area of 1,380 km2, is an average of 15 m deep, and is connected to the Pacific Ocean by a 7 km wide strait at its south end. The average retention time of seawater varies seasonally but is reported to be approximately 31 days [1]. Central Tokyo is located on the west side of the bay, which is surrounded by a zone of large cities that forms the heart of Japan, and has a total population of 38 million. The catchment basins of rivers flowing into Tokyo Bay from the greater Tokyo region occupy a land area of 9,100 km2, and the total quantity of inflowing river water fluctuates greatly, but averages approximately 1.4 × 107 m3?day-1. The major rivers are the Edogawa, Old-Edogawa, Arakawa, Tamagawa, Sumidagawa, and Tsurumigawa. Even though Tokyo Bay is closed, its seawater flow is complex. In addition to tidal currents, permanent currents flow throughout the bay, and the surface water movement is dominated by circular drifts: clockwise in the winter and counterclockwise in the summer. The bottom water moves in the opposite direction to the flow of the surface water. The pelagic water from the Pacific Ocean flows north on the bottom inside the bay until it reaches the Bay’s deepest section [1].

Aircraft monitoring of the 134+137Cs precipitation was conducted by the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT) [2], and the results were published by the Geospatial Information Authority of Japan (GSI) [3], showing that the catchment basin of Edogawa River was contaminated from 30 to 100 kBq?m-2 by radiocesium discharged from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, but the radioactive contamination levels in the catchment basins of the Bay’s other rivers were lower than those in the catchment basin of Edogawa. Radioactive materials precipitated on the ground surface in the greater Tokyo region are, as in the case of artificially discharged environmental contaminants, presumably carried by these rivers until they finally flow into Tokyo Bay.

Many reports outlining the FDNPP accident have already been released to the public [4?7]. However, many of these are analyses of the accident process, whereas few address the environmental radioactive contamination that was caused [2, 8?10]. In particular, the movement in the greater Tokyo region of radioactive contamination produced by the FDNPP accident has been insufficiently analyzed. Nevertheless, after the accident, high concentration radioactive plumes arrived in the greater Tokyo region, radionuclides washout with precipitation (rainfall) on March 16 and 22 in 2011 [11]. Clarifying the movement of environmental radioactive contaminants in the heavily populated greater Tokyo region is an important issue related to the problem of low dose exposure to large populations. Evaluation of the migration process of radiocesium from the Tokyo metropolitan area also is important from the viewpoint of reduction and decontamination of radioactive contamination in these areas. In our previous paper, the behavior of radioactive contaminants of the soil in the Tokyo metropolitan area was discussed [12]. It is estimated that 10 to 22% of the radiocesium precipitated in the surface soil and migrated to Tokyo Bay via rivers in the five years after the FDNPP accident.

This study was a continuous time-series analysis of the distribution and fluctuation of radiocesium in sediments and waters in Tokyo Bay and in the rivers flowing into Tokyo Bay starting in August 2011, immediately after the FDNPP accident. Based on the results, the process of the movement from the land and deposition in Tokyo Bay of radiocesium that was precipitated in the greater Tokyo region via the FDNPP accident were evaluated. However, before the FDNPP accident the Chernobyl accident and the Three Mile Island (TMI) accident affected many affecting people. TMI was located about 150 km west of Washington DC but because it avoided the destruction of the pressure vessel, the emission of radioactive nuclides to the environment is only rare gas nuclides, and the release amount of 131I is estimated to be about 0.5 TBq [13,14]. In the case of the Chernobyl accident, Kiev City was located 130 km south, and 4 million residents lived in that metropolitan area. It was reported at the Chernobyl Forum by the IAEA in 2006 [15] that radioactive plume flew to Kyiv City by the north wind on May 1, 1986 immediately after the accident. However, regulations on information disclosure were made by the Soviet government at the time, and the actual state and dynamics of radioactive contamination in Kiev City are still hardly understood even now. Of course, do not forget the radioactive contamination by the atomic bombs of Hiroshima and Nagasaki. The results of our investigation on the environmental dynamics of 60 years after radiation exposure in Nagasaki has already been reported [16?18]. From such a viewpoint, we think that the FDNPP accident was the first time that an urban region as densely populated as Tokyo was contaminated by radioactive material over a wide area.

Studies on the behavior of radiocesium in an urban environment have been performed through simulations [19], but fluctuation in this radionuclide’s spatiotemporal distribution has not been monitored nor analyzed over wide areas for long periods. Furthermore, the behavior of cesium as an alkaline element is often complicated and unknown in the estuary where seawater and river water mix [20,21]. In this study, the important roles that Tokyo Bay and rivers flowing into it play in the movement of radiocesium contaminants and the transport and accumulation mechanisms of such in the greater Tokyo region have been clarified.

The Nuclear Regulation Authority of the Japanese Government (NRA) has monitored the radioactive contamination derived from the FDNPP accident in the surface sediment of Tokyo Bay since June 2013 [22]. The Japan Coast Guard (JCG) has also been measuring the radioactive contamination of surface sediments in Tokyo Bay since 1981 [23]. On the other hand, survey results of radiocesium contamination in the Tokyo Bay area immediately after the accident have been published [24]. However, since their monitoring is limited spatiotemporally, it is insufficient to evaluate the dynamics of radioactive contamination throughout the environments of Tokyo Bay.

Sampling and analytical methods

Material and methods

Sediment and water were sampled in Tokyo Bay and in the rivers in its catchment basin. The locations are shown in Fig 1. Sampling was performed at the same points one to seven times during the study period, which ran from August 20, 2011, until July 12, 2016. Sediment samples were collected at 77 points in Tokyo Bay, 10 points in Edogawa River, and 6 points in Sakagawa River. Of the sediment samples collected, 68 were core sediments and 142 surface sediments. Sediment cores were sampled at Point S1 (Fig 1), where Sakagawa flows into Edogawa, to evaluate the role of Sakagawa in the process of transporting radiocesium. To compare with sediment, soil samples were also collected from the 14 points shown in Fig 1B.

Fig 1. Study areas and sampling points.
Geographical distribution of the radiocesium precipitation is indicated by the values for eight months after the accident, adapted from “Extension Site of Distribution Map of Radiation Dose, etc.” [3]. (a) Study area. (b) Sampling points in the Edogawa river system. (c) Sampling points in the Tokyo Bay area. V: Tamagawa estuary, W: Sumidagawa estuary, X: Old-Edogawa estuary, Y: Off the Old-Edogawa estuary, Z: Center of Tokyo Bay, Aqua Line: Cross road of Tokyo Bay. River water in Old-Edogawa flows in the direction of the blue arrow in Fig 1C.
https://doi.org/10.1371/journal.pone.0193414.g001

Sediment core sampling was done using an acrylic pipe with a diameter of 10 cm and length of 100 cm. The core samples were collected by a diver pushing the pipe into the seabed by hand. Core samples of 20 to 80 cm length were obtained. Surface sediment specimens were sampled from a boat using an Ekman-Birge bottom sampler. Then, on the boat, after the sediments were collected, the material was inserted into an acrylic pipe with a diameter of 5 cm and length of 10 cm to obtain samples a top 5 cm sediment. Most of soil and sediment samples consisted of silt and sand with a particle size of 2 mm or less. However, more pebbles, plant pieces, shell fragments, etc. were removed with tweezers. Grain size sorting by sieve was not done. The sediments were pushed out of the pipes, cut into 1 or 2 cm thick slices in the depth direction, and then thermally dried to a constant weight in a 60°C oven to remove the water from the sediments. The dried samples were pulverized in an agate mortar, and then the radioactivity of the samples was measured. Water samples were obtained from the surface of the water by lowering buckets from boats. Divers obtained bottom water from about 1 m above the seabed. Without filtering suspended materials out of the water, the radiocesium in 20 L of sample water was concentrated using an ammonium phosphomolybdate (AMP) method [25]. After standing overnight, the AMP precipitate was filtrated and collected on a membrane filter (pore size 0.8 μm), then the radioactivity of the dried AMP precipitate was measured. In this way, it was confirmed in a preliminary experiment that the ionic and suspended radiocesium in the sample water can be recovered quantitatively.

Measurement of radioactivity

Radionuclides in the samples were quantified by connecting a 4096-multichannel pulse height analyzer (Lab Equipment, MCA600) to a low energy HPGe detector (ORTEC, LO-AX/30P) shielded in lead 10 cm thick, sealing the specimens inside a plastic container with a diameter of 5.5 cm and depth of 2.0 cm, then measuring them via γ-ray spectrometry. The Ge detector calculated the geometric efficiency relative to the sample weight using the American NIST (National Institute of Standards and Technology) Environmental Radioactivity Standards, SRM 4350B (River Sediment) and SRM 4354 (Freshwater Lake Sediment), and the efficiency was corrected to within a range of 2 to 30 g of the sample weight [26]. The measurement time was set so that the counting error would be less than 5% according to the radioactive intensity of the samples. 134Cs (605 keV) and 137Cs (662 keV) were quantified in this study. A 134Cs solution with known concentration was used to correct the sum peak effect for 134Cs counting. The detection limits of 134Cs and 137Cs under appropriate conditions were 0.6 Bq?kg-1 in sediment samples and 0.3 mBq?L-1 in water samples. Radiocesium activity was indicated by the values per sampling day, but was corrected for radioactive decay to the value on March 16, 2011, as necessary. In that case, it is denoted as “corrected activity.”

Measurements of heavy metals and particle size distributions in the sediments

The heavy metals in the sediments were measured via an XRF method (Rigaku, ZSX-Primus Ⅱ) using the NIST SRM 1646 (Estuarine Sediment) as the standard sample. Sample measured were made from cellulose powder pressed into 4 cm diameter aluminum ring 0.4 ton?cm-2, and then 1.2 g of powdered sample was placed on the disk and repressed at 1.6 ton?cm-2. The correction of matrix effect was achieved by X-ray intensity ratio of peak to back ground for each element [27]. Mercury in the sediments was measured via a heating-vaporization atomic absorption spectrometry (Hiranuma, HG-300). The particle size distribution of the wet sediment samples was measured using a laser diffractometer (Shimadzu, SALD-3000) with a measurement range of particle size 0.05 to 3000 μm. Dispersion of sedimentary particles was carried out via ultrasonic irradiation (Shimadzu, SUS-200, 42 kHz) using sodium hexametaphosphate as a dispersant. In this paper, the particle size obtained is presented as the volume-based average particle diameter.

Results

Spatiotemporal distribution of radiocesium in Tokyo Bay sediment

All measured values obtained in this study are shown in S1?S4 Tables of the supporting information file. Geographic coordinates of sampling points are also shown in S5 Table. Sampling was done on different days; hence, the radiocesium activities are shown after the radioactive decay correction based on the value of March 16, 2011. A plurality of measured values collected at different times were subjected to statistical processing. Fig 2 (S6 Table) shows the spatial distribution of the 134+137Cs activity (total value of 134Cs and 137Cs) in the surface layer of the sediment, from 0 to 5 cm depth. When multiple measurements were done at the same point, the 134+137Cs activity was evaluated based on the value in a weighted average with the counting error. The deviation of the weighted average approximated according to the law of uncertainty propagation.

Fig 2. Activities of 134+137Cs in the surface sediments throughout the Tokyo Bay water system.
Sediment samples were collected from August 20, 2011, to July 12, 2016. The activity of 134+137Cs was radioactive decay corrected based on the value of March 16, 2011. The value of activity is shown as an average of the values from the surface to 5 cm depth. When there are multiple data at the same point, the activity is expressed as a weighted average value for the counting error.
https://doi.org/10.1371/journal.pone.0193414.g002

The highest 134+137Cs activity among all measured values in Tokyo Bay was 1340 ± 13 Bq?kg-1, found in the surface sediments sampled at Point 01 in the Old-Edogawa estuary on November 1, 2012. As shown in Fig 2, the 134+137Cs activity in surface sediment in Tokyo Bay was ranked from high to low contamination level as the Old-Edogawa estuary (X), off the Old-Edogawa estuary (Y), center of Tokyo Bay (Z), Tamagawa estuary (V), and Sumidagawa estuary (W). Throughout the survey period, the 134+137Cs activity of the surface sediments was highest in the Area X, and fell remarkably towards the Area Z. The 134+137Cs activity indicated by the weighted average value was 424 ± 1 Bq?kg-1 (78?1340 Bq?kg-1, n = 55) for X, 131 ± 1 Bq?kg-1 (40?371 Bq?kg-1, n = 40) for Y, and 17 ± 0.3 Bq?kg-1 (1?162 Bq?kg-1, n = 50) for Z. In the Tamagawa estuary (V), which flows through farmland in western metropolitan Tokyo, the weighted average activity was 57 ± 1 Bq?kg-1 (5?234 Bq?kg-1, n = 7). In the Sumidagawa mouth (W), which flows through central Tokyo, it was 103 ± 2 Bq?kg-1 (32?374 Bq?kg-1, n = 16). Both are lower activities than that of the Old-Edogawa estuary (X).

We inferred the inventory and flux of radiocesium accumulation in Tokyo Bay sediment from the catchment basin owing to the FDNPP accident for the five years studied. Table 1 shows the inventory, flux, and 134Cs/137Cs activity ratio of radiocesium in the sediments collected from the Edogawa water system and Tokyo Bay. The 134Cs/137Cs activity ratio in 117 sediment samples (Table 1, S6 Table), with counting error of the radioactivity measurements within 5%, was 1.006 ± 0.003 (weighted average value), which conforms to the 134Cs/137Cs ratio of radiocesium discharged by the FDNPP accident [28?30].

 

ハランの花粉媒介はキノコバエ

 投稿者:  投稿日:2018年 3月 1日(木)23時12分32秒 KD182250243012.au-net.ne.jp
  末次 健司
https://www.facebook.com/kenji.suetsugu.5/posts/965997966890900?pnref=story
紫色で多肉質の変わった姿をした花を地面にめり込んで咲かせることから「世界で最も変わった花」の一つと言われていた「ハラン」の花粉の運び手を明らかにした論文をEcology誌に発表しました.

http://dx.doi.org/10.1002/ecy.2021

世界で最も変わった花というと何を思い浮かべるでしょうか?1m以上の花をつけるラフレシアやショクダイオオコンニャクを思い浮かべる人も多いかもしれません.しかし実は,「世界で最も変わった花」といわれている植物が日本に分布しています.

それはハランという植物です.ハラン(葉蘭)は,名前に「蘭」とつきますが,キジカクシ科という科に属する植物です. 寿司などの食品に付属する緑色のプラスチック装飾品“バラン”は、ハランを真似て作られた物です。

ランは、紫色で多肉質の変わった姿の花を、ちょうど地面にめり込んだような格好で咲かせますが,花粉の運び手は、「ナメクジ」や「ヨコエビ」などの土壌動物であるという報告がなされてきました。

他にこれらを運び手とする花がほとんどないことから、ハランは「世界で最も変わった花」と呼ばれており,数少ない土壌動物媒花として送粉生態学の教科書にも取り上げられていました。しかしこれまでの報告には、自生地での観察ではない,もしくは,直接観察した訳ではないなどの欠点もありました.

そこで,今回私たちは,ハランの花に訪れる動物を,自生地である黒島において,観察を行いました.その結果,ナメクジは全く訪れないことやヨコエビが花に訪れる回数は極めて少ないことを突き止めました.一方、有効な花粉の運び手として浮かび上がってきたのはキノコバエでした.

今回花に訪れていたキノコバエ類は,いずれも幼虫がキノコを食べることが明らかになっている種です.つまり,ハランの奇妙な花姿は,キノコに擬態することでキノコバエ類を騙して,花粉を運ばせようとするしたたかな戦略であることが示唆されました.

キノコバエ類に受粉を託す植物は珍しい存在ですが,ほかにも知られています.今回の研究は,これまで教科書で紹介されるほど長く信じられていた風変りな仮説を直接観察によって覆し,ハランが,翅を持たない土壌動物ではなく,他の植物と同じように飛ぶ昆虫によって花粉が運ばれていることを明らかにしました.「世界で最も変わった花」は,そこまで風変わりではなかったといえるかもしれません.

Subterranean flowers of Aspidistra elatior are mainly pollinated by not terrestrial amphipods but fungus gnats
http://onlinelibrary.wiley.com/doi/10.1002/ecy.2021/full

The genus Aspidistra (Asparagaceae) comprises over 130 species of herbaceous plants (Chase et al. 2009), most of which are distributed in Southeast Asia (Vislobokov et al. 2013). However, even though most Aspidistra species are common, they are also inconspicuous, and the leaf litter of forest habitats usually covers their flowers and fruits, both of which are found close to ground level (Fig. 1A). Therefore, the Aspidistra flower is often considered cryptic (Phonsena and De Wilde 2010). Nevertheless, the flowers are extraordinarily diverse, and their morphology is considered critical to species delimitation (Vislobokov et al. 2013, Tillich 2008).

Figure 1.
(A) Aspidistra elatior flower in forest litter. (B) Longitudinal section of A. elatior flower. (C) The fungus gnat Cordyla sixi (Mycetophilidae) exiting gaps between the stigma lobes and the perianth tube and carrying a lot of A. elatior pollen grains. (D) Diaprid wasp exiting a gap between the stigma lobes and the perianth tube and carrying a few A. elatior pollen grains.

The pollination of biology of Aspidistra is interesting because of the extreme diversity in its floral morphology, its inconspicuous appearance, and the forest litter which covers them (Vislobokov et al. 2013). Because of these reasons, little is known about the pollinators of almost all the species. Nevertheless, the unusual flowers suggest biotic pollination, since pollen grains are hidden under each flower's stigma and because the flowers look like insect traps (Vislobokov et al. 2013). The stamens of A. elatior positioned within a perianth chamber under a large stigma (Fig. 1B) that has a receptive upper surface, thereby rendering self-pollination impossible (Buchenau 1867). One researcher, Delpino (1868) provided compelling evidence for cross-pollination in cultivated A. elatior; he located Aspidistra pollen grains along the trajectories of floral visitors exiting a small opening formed between the stigmatic margin and the perianth tube. In addition, Wilson (1889) suggested that A. elatior was pollinated by slugs, a hypothesis subsequently adopted by numerous studies as a rare example of angiosperm flowers being pollinated by mollusks (e.g., Richards 1986).

More recently, Kato (1995) conducted the first investigation of A. elatior visitors in the species’ native habitat and failed to find any evidence of pollination by slugs. Instead, the author observed Platorchestia japonica (Amphipoda) feeding on pollen, which suggested that A. elatior could be pollinated by the terrestrial crustaceans (Kato 1995). Pollination by crustaceans and collembolans has also been suspected in the introduced population of A. elatior (Conran and Bradbury 2007). Taken together, Vislobokov et al. (2013) noted that the information known about the floral ecology of A. elatior suggests it has the most unusual pollination ecology among all angiosperms. However, the novel observations by Kato (1995) and Conran and Bradbury (2007) relied on collected flowers that were studied through dissection. Therefore, without direct observations in the field, the study could have underestimated the role of more quickly moving visitor groups.

In order to further elucidate the pollination biology of A. elatior, we conducted the first direct observation of A. elatior visitors in the species’ natural habitat. Aspidistra elatior is widely cultivated in both China and Japan but is indigenous to only a few small islands in the southern part of Japan (Liang and Tamura 2000). Therefore, we made direct observations of pollinators visiting A. elatior flowers in evergreen oak forests at altitudes between ca. 300?600 m on Kuroshima Island, Kagoshima Prefecture, Japan, where A. elatior is abundant in the understory. We performed the observations of floral visitors for ca. 30 h in mid- to late April of 2015?2016, covering all periods of a 24 h cycle, and red light was used during nocturnal observations to minimize the effect of light on the visitors. We also tagged 253 flowers in mid-April 2016 and assessed the fruit sets under natural condition in late October 2016.

We observed that five individuals of fungus gnats visited and penetrated thorough the gaps between the stigma lobes and perianth tube, three of which were captured for the precise identification. They were identified as Cordyla sixi (Mycetophilidae), newly recorded from Japan, and Bradysia sp. (Sciaridae; Table 1). In addition, all captured fungus gnats were male, thereby providing no evidence that the flowers serve as brood sites. When a fungus gnat visited a flower, it landed on the upper surface of the stigma so that, if the fungus gnat had previously visited another flower, cross-pollination would occur. The fungus gnats often penetrated under the stigma by entering small openings between the stigma lobes and perianth tube. Therefore, when the fungus gnats exited, they were covered with pollen grains (Fig. 1C). The fungus gnats would often try to penetrate under the stigma several times before succeeding and, then, would remain there for up to dozens of seconds, before exiting through the gaps. Because flowers of Aspidistra do not produce nectar and adult fungus gnats do not feed on pollen grains, we concluded that fungus gnats did not receive any benefits from this interaction.

Table 1. Composition of floral visitors to Aspidistra elatior

Interestingly, a wasp in the family Diapriidae was also documented as a potential pollinator. We observed only one, but the wasp penetrated under the stigma through the gaps between the stigma lobes and perianth tube, and when the wasp exited, it was covered with pollen grains (Fig. 1D). The diaprid wasps are parasitoids that attack the larvae of fungus gnats (Gauld et al. 1988), and they have also been documented to pollinate Cypripedium fasciculatum, the morphology of which is similar to species pollinated primarily by fungal gnats (Lipow et al. 2002). Therefore, the similar appearance of A. elatior and mushroom fruit bodies may help attract fungus gnats, as well as their natural enemies (Tillich 2005). In fact, larva of both C. sixi and Bradysia sp. are known as the fungivore.

As reported by previous studies (Kato 1995, Conran and Bradbury 2007), we also observed small soil invertebrates, such as Ceratophysella denticulata and Platorchestia japonica, in the A. elatior flowers. Therefore, we cannot exclude the role of soil invertebrates as supplemental pollinators. However, these visitors would play relatively minor roles as pollinators since they are only able to carry a few pollen grains, even after penetrating the stigma. The flowers were also visited by two species of ants (e.g., Pachycondyla nakasujii and Nylanderia flavipes), but the behavior of the ants observed in the field was much less focused than that of the fungus gnats. Instead, the ants primarily appeared to walk around the perianth lobe and stigma, and the ants were rarely observed penetrated under the stigma using the gaps used by the fungus gnats.

We predicted that the fungus gnats are the most effective pollinator of A. elatior since (1) they were observed on multiple occasions departing from Aspidistra flowers with a lot of pollen grains on their bodies, (2) they were the dominant flying insects that visited the Aspidistra flowers, and (3) the flowers that they visited often developed fruits (2 fruits/5 flowers) despite the population's overall low fruit set (12 fruits/253 flowers). Since experienced insects usually avoid non-rewarding plants due their associative learning ability, the deceptive pollinator attraction strategy could account for the low pollination visitation rate (Tremblay et al. 2004), and this could contribute to the low reproductive success of these plants. In addition, the size of the fungus gnats allows them to pass through the gaps between the stigma lobes and perianth, enter the chamber, and locate the stamens. Therefore, we speculate that the methodology used by Kato (1995) may have been insufficient for detecting dipteran visitors, likely owing to their short duration of their visitations.

Indeed, several aspects of A. elatior's floral morphology, such as its superficial similarity to mushroom fruit bodies, suggest that Aspidistra species are pollinated by fungus gnats (Tillich 2005). We also found that the A. elatior in our study site emitted a strong musty odor, while other Aspidistra flowers are often described as odorless. Therefore, the fungus gnats may be attracted by both visual and chemical mimicry. It is also interesting to note that Cordyla species, that are the main pollinators of A. elatior, also pollinate Heterotropa which is also considered a mushroom mimic (Sugawara 1988).

Vislobokov et al. (2013, 2014) also observed that flies pollinate some species of the genus Aspidistra. Therefore, in combination with the results of the present study, we suspected that dipteran pollination would be common among Aspidistra species. However, pollination biology of each Aspidistra species will still be very diverse. For example, the pollinators of the two other species observed so far belong to different dipteran families; A. phanluongii is pollinated by flies of genus Megaselia (Phoridae) (Vislobokov et al. 2013), whereas A. xuansonensis is pollinated by gall midges, whose larvae are able to grow in the pollen mass (Vislobokov et al. 2014). Further study is needed to elucidate the diversity of unique pollination systems in Aspidistra.
Acknowledgments

We thank Drs Taizo Nakamori, Kyohei Watanabe and Shigeko Fukumoto for their assistance with insect identification. This work was financially supported by the JSPS KAKENHI (Grant Number 17H05016).
 

縄文時代から現在までの、日本国内における草原性チョウ類の歴史

 投稿者:  投稿日:2018年 2月26日(月)23時16分5秒 KD182250243007.au-net.ne.jp
  Naoyuki NAKAHAMA? @naoyukinkhm
https://twitter.com/naoyukinkhm/status/968042880978755584
(論文出版) 縄文時代から現在までの、日本国内における草原性チョウ類の歴史を解明しました。https://www.nature.com/articles/s41437-018-0057-2
草原性チョウ類の一種コヒョウモンモドキを材料にDNA解析を行い、長期的視点(過去1万年間)と短期的視点(過去30年間)から個体数の変遷を明らかにしました。

本研究から、草原が増加する過去6000年前は、草原性チョウ類の個体数が増加していたものの、草原が減少する過去30年間は個体数・遺伝的多様性ともに減少していたことが明らかとなりました。まさに、草原も草原性生物も「栄枯盛衰」をたどったということになります。

日本の温帯草原は、縄文時代以降の人間活動(火入れ、伐採、草刈)により面積を増加させてきました。20世紀初頭には国土の約1割が草原だったといわれています。しかし、化石燃料への依存を機に、草原維持の必要性が小さくなりました。その結果面積が急減し、現在草原生態系は危機的状況となっています。
1件の返信 3件のリツイート 4 いいね

こうした中、草原性生物はどのような歴史をたどったのでしょうか。草原性チョウ類の一種コヒョウモンモドキ(絶滅危惧IB類)を材料に用いて、個体数の変遷を明らかにいたしました。
1件の返信 1件のリツイート 4 いいね

ミトコンドリアDNA配列から推定をした結果、およそ6000年前には個体数が大きく増加したことが示されました。これは、縄文時代以降に日本国内で草原面積が増加したという先行研究と一致します。

一方で、1980年代以降について、標本と現在のサンプルを用いて集団遺伝解析を行いました。その結果、1980年代以降、コヒョウモンモドキは個体数・遺伝的多様性ともに大きく減少していました。減少の理由は温暖化ではなく、草原面積の減少であることが統計解析から示されました。

過去の草原の増加も、現在の草原の減少も、人間活動が大きな原因となっています。したがって、人間活動の変化が、草原と草原性生物の「栄枯盛衰」をもたらしたといえます。

本研究では、1980年代から2010年代に採集されたチョウの乾燥標本から遺伝情報を取り出しています。標本を解析させてくださいました皆様、並びに博物館、大学、研究所の皆様に心から厚く御礼申し上げます。ありがとうございました。

最後に今回のサンプリングでは、成虫の後翅脈のごく一部のみをDNA用サンプルとして切り取ってすぐに放蝶しており、チョウの成虫を捕殺しないように配慮しています。また、標本の解析の際にも外骨格を破壊せずにDNAを抽出することで、標本へのダメージを最小限に抑えています。
 

イザヤ55章

 投稿者:  投稿日:2018年 2月23日(金)21時53分24秒 KD182250243017.au-net.ne.jp
  「雨も雪も、ひとたび天から降ればむなしく天に戻ることはない。それは大地を潤し、芽を出させ、生い茂らせ、種まく人には種を与え、食べる人には糧を与える。そのように、私の口から出る私の言葉も、空しくは、私のもとに戻らない」イザヤ55章  

リュウキュウベンケイとコウトウシュウカイドウの園芸利用

 投稿者:  投稿日:2018年 2月22日(木)22時01分0秒 KD182250243003.au-net.ne.jp
  3)園芸品種作出に関する調査(リュウキュウベンケイ・コウトウシュウカイドウ)
https://churashima.okinawa/ocrc/801/828

リュウキュウベンケイソウ

ちゅららダブルピンク2

コウトウシュウカイドウとBegonia chloroneura、B.nigritarumを交配
 

A Comprehensive and Dated Phylogenomic Analysis of Butterfli

 投稿者:  投稿日:2018年 2月17日(土)01時34分40秒 KD182250243014.au-net.ne.jp
  A Comprehensive and Dated Phylogenomic Analysis of Butterflies
http://www.cell.com/current-biology/fulltext/S0960-9822%2818%2930094-0#.WoXVfUFgt5s.twitter
抜粋

Highlights
?Phylogenomic data provide a novel view of broad butterfly evolutionary relationships
?Most current diversity originated after the K-Pg mass extinction
?Many accepted higher taxa are para- or polyphyletic
?Ant association originated three times independently in blues and metalmarks
Summary
Butterflies (Papilionoidea), with over 18,000 described species [1], have captivated naturalists and scientists for centuries. They play a central role in the study of speciation, community ecology, biogeography, climate change, and plant-insect interactions and include many model organisms and pest species [2, 3]. However, a robust higher-level phylogenetic framework is lacking. To fill this gap, we inferred a dated phylogeny by analyzing the first phylogenomic dataset, including 352 loci (> 150,000 bp) from 207 species representing 98% of tribes, a 35-fold increase in gene sampling and 3-fold increase in taxon sampling over previous studies [4]. Most data were generated with a new anchored hybrid enrichment (AHE) [5] gene kit (BUTTERFLY1.0) that includes both new and frequently used (e.g., [6]) informative loci, enabling direct comparison and future dataset merging with previous studies. Butterflies originated around 119 million years ago (mya) in the late Cretaceous, but most extant lineages diverged after the Cretaceous-Paleogene (K-Pg) mass-extinction 65 mya. Our analyses support swallowtails (Papilionidae) as sister to all other butterflies, followed by skippers (Hesperiidae) + the nocturnal butterflies (Hedylidae) as sister to the remainder, indicating a secondary reversal from diurnality to nocturnality. The whites (Pieridae) were strongly supported as sister to brush-footed butterflies (Nymphalidae) and blues + metalmarks (Lycaenidae and Riodinidae). Ant association independently evolved once in Lycaenidae and twice in Riodinidae. This study overturns prior notions of the taxon’s evolutionary history, as many long-recognized subfamilies and tribes are para- or polyphyletic. It also provides a much-needed backbone for a revised classification of butterflies and for future comparative studies including genome evolution and ecology.
 

オレンジの進化と分類

 投稿者:  投稿日:2018年 2月 9日(金)03時43分0秒 KD182250243002.au-net.ne.jp
  Genomics of the origin and evolution of Citrus
https://www.nature.com/articles/nature25447
抜粋

Abstract

The genus Citrus, comprising some of the most widely cultivated fruit crops worldwide, includes an uncertain number of species. Here we describe ten natural citrus species, using genomic, phylogenetic and biogeographic analyses of 60 accessions representing diverse citrus germ plasms, and propose that citrus diversified during the late Miocene epoch through a rapid southeast Asian radiation that correlates with a marked weakening of the monsoons. A second radiation enabled by migration across the Wallace line gave rise to the Australian limes in the early Pliocene epoch. Further identification and analyses of hybrids and admixed genomes provides insights into the genealogy of major commercial cultivars of citrus. Among mandarins and sweet orange, we find an extensive network of relatedness that illuminates the domestication of these groups. Widespread pummelo admixture among these mandarins and its correlation with fruit size and acidity suggests a plausible role of pummelo introgression in the selection of palatable mandarins. This work provides a new evolutionary framework for the genus Citrus.
Main

The genus Citrus and related genera (Fortunella, Poncirus, Eremocitrus and Microcitrus) belong to the angiosperm subfamily Aurantioideae of the Rutaceae family, which is widely distributed across the monsoon region from west Pakistan to north-central China and south through the East Indian Archipelago to New Guinea and the Bismarck Archipelago, northeastern Australia, New Caledonia, Melanesia and the western Polynesian islands1. Native habitats of citrus and related genera roughly extend throughout this broad area (Extended Data Fig. 1a and Supplementary Table 1), although the geographical origin, timing and dispersal of citrus species across southeast Asia remain unclear. A major obstacle to resolving these uncertainties is our poor understanding of the genealogy of complex admixture in cultivated citrus, as has recently been shown2. Some citrus are clonally propagated apomictically3 through nucellar embryony, that is, the development of non-sexual embryos originating in the maternal nucellar tissue of the ovule, and this natural process may have been co-opted during domestication; grafting is a relatively recent phenomenon4. Both modes of clonal propagation have led to the domestication of fixed (desirable) genotypes, including interspecific hybrids, such as oranges, limes, lemons, grapefruits and other types.

Under this scenario, it is not surprising that the current chaotic citrus taxonomy?based on long-standing, conflicting proposals5,6?requires a solid reformulation consistent with a full understanding of the hybrid and/or admixture nature of cultivated citrus species. Here we analyse genome sequences of diverse citrus to characterize the diversity and evolution of citrus at the species level and identify citrus admixtures and interspecific hybrids. We further examine the network of relatedness among mandarins and sweet orange, as well as the pattern of the introgression of pummelos among mandarins for clues to the early stages of citrus domestication.
Diversity and evolution of the genus Citrus

To investigate the genetic diversity and evolutionary history of citrus, we analysed the genomes of 58 citrus accessions and two outgroup genera (Poncirus and Severinia) that were sequenced to high coverage, including recently published sequences2,3,7 as well as 30 new genome sequences described here. For our purpose, we do not include accessions related by somatic mutations. These sequences represent a diverse sampling of citrus species, their admixtures and hybrids (Supplementary Tables 2, 3 and Supplementary Notes 1, 2). Our collection includes accessions from eight previously unsequenced and/or unexamined citrus species, such as pure mandarins (Citrus reticulata), citron (Citrus medica), Citrus micrantha (a wild species from within the subgenus Papeda), Nagami kumquat (Fortunella margarita, also known as Citrus japonica var. margarita), and Citrus ichangensis (also known as Citrus cavaleriei; this species is also considered a Papeda), as well as three Australian citrus species (Supplementary Notes 3, 4). For each species, we have sequenced one or more pure accessions without interspecific admixture.

Local segmental ancestry of each accession can be delineated for both admixed and hybrid genotypes, based on genome-wide ancestry-informative single-nucleotide polymorphisms (Supplementary Note 5). Comparative genome analysis further identified shared haplotypes among the accessions (Supplementary Notes 6, 7). In particular, we demonstrate the F1 interspecific hybrid nature of Rangpur lime and red rough lemon (two different mandarin?citron hybrids), Mexican lime (a micrantha?citron hybrid) and calamondin (a kumquat?mandarin hybrid), and confirm, using whole-genome sequence data, the origins of grapefruit (a pummelo?sweet orange hybrid), lemon (a sour orange?citron hybrid) and eremorange (a sweet orange and Eremocitrus glauca (also known as Citrus glauca) hybrid). We also verified the parentage of Cocktail grapefruit, with low-acid pummelo as the seed parent and King and Dancy mandarins as the two grandparents on the paternal side. The origin of the Ambersweet orange is similarly confirmed to be a mandarin?sweet orange hybrid with Clementine as a grandparent. We have previously shown that sour orange (cv. Seville) (Citrus aurantium) is a pummelo?mandarin hybrid, and have analysed the more complex origin of sweet orange (Citrus sinensis)2. Re-analysing sequences from ten cultivars of sweet orange3 shows that they are all derived from the same genome by somatic mutations, and were thus not included in our study.

We identified ten progenitor citrus species (Supplementary Note 4.1) by combining diversity analysis (Extended Data Table 1), multidimensional scaling and chloroplast genome phylogeny (Extended Data Fig. 1b). The first two principal coordinates in the multidimensional scaling (Fig. 1a) separate three ancestral (sometimes called ‘fundamental’) Citrus species associated with commercially important types8,9?citrons (C. medica), mandarins (C. reticulata) and pummelos (Citrus maxima)?and display lemons, limes, oranges and grapefruits as hybrids involving these three species. The nucleotide diversity distributions (Fig. 1b) show distinct scales for interspecific divergence and intraspecific variation, and reflect the genetic origin of each accession. Hybrid accessions (sour orange, calamondin, lemon and non-Australian limes) with ancestry from two or more citrus species are readily identified on the basis of their higher segmental heterozygosity (1.5?2.4%) relative to intraspecific diversity (0.1?0.6%). Other citrus accessions show bimodal distributions in heterozygosity (sweet orange, grapefruits and some highly heterozygous mandarins) due to interspecific admixture, a process that generally involves complex backcrosses. Among the pure genotypes without interspecific admixture, citrons show significantly lower intraspecific diversity (around 0.1%) than the other species (0.3?0.6%). The reduced heterozygosity of citrons, a mono-embryonic species, is probably due to the cleistogamy of its flowers10, a mechanism that promotes pollination and self-fertilization in unopened flower buds, which in turn reduces heterozygosity.

Figure 1: Genetic structure, heterozygosity and phylogeny of Citrus species.
a, Principal coordinate analysis of 58 citrus accessions based on pairwise nuclear genome distances and metric multidimensional scaling. The first two axes separate the three main citrus groups (citrons, pummelos and mandarins) with interspecific hybrids (oranges, grapefruit, lemon and limes) situated at intermediate positions relative to their parental genotypes. b, Violin plots of the heterozygosity distribution in 58 citrus accessions, representing 10 taxonomic groups as well as 2 related genera, Poncirus (Poncirus trifoliata, also known as Citrus trifoliata) and Chinese box orange (Severinia). White dot, median; bar limits, upper and lower quartiles; whiskers, 1.5× interquartile range. The bimodal separation of intraspecies (light blue) and interspecies (light pink) genetic diversity is manifested among the admixed mandarins and across different genotypes including interspecific hybrids. Three-letter codes are listed in parenthesis with additional descriptions in Supplementary Table 2. c, Chronogram of citrus speciation. Two distinct and temporally well-separated phases of species radiation are apparent, with the southeast Asian citrus radiation followed by the Australian citrus diversification. Age calibration is based on the citrus fossil C. linczangensis16 from the Late Miocene (denoted by a filled red circle). The 95% confidence intervals are derived from 200 bootstraps. Bayesian posterior probability is 1.0 for all nodes. d, Proposed origin of citrus and ancient dispersal routes. Arrows suggest plausible migration directions of the ancestral citrus species from the centre of origin?the triangle formed by northeastern India, northern Myanmar and northwestern Yunnan. The proposal is compatible with citrus biogeography, phylogenetic relationships, the inferred timing of diversification and the paleogeography of the region, especially the geological history of Wallacea and Japan. The red star marks the fossil location of C. linczangensis. Citrus fruit images in c and d are not drawn to scale.

The identification of a set of pure citrus species provides new insights into the phylogeny of citrus, their origins, evolution and dispersal. Citrus phylogeny is controversial1,5,6,11,12, in part owing to the difficulty of identifying pure or wild progenitor species, because of substantial interspecific hybridization that has resulted in several clonally propagated and cultivated accessions. Some authors assign separate binomial species designations to clonally propagated genotypes1,6. Our nuclear genome-based phylogeny, which is derived from 362,748 single-nucleotide polymorphisms in non-genic and non-pericentromeric genomic regions, reveals that citrus species are a monophyletic group and establishes well-defined relationships among its lineages (Fig. 1c and Supplementary Note 8). Notably, the nuclear genome-derived phylogeny differs in detail from the chloroplast-derived phylogeny (Extended Data Fig. 1). This is not unexpected, as chloroplast DNA is a single, non-recombining unit and is unlikely to show perfect lineage sorting during rapid radiation (Supplementary Note 8.3).

The origin of citrus has generally been considered to be in southeast Asia1, a biodiversity hotspot13 with a climate that has been influenced by both east and south Asian monsoons14 (Supplementary Note 9). Specific regions include the Yunnan province of southwest China15, Myanmar and northeastern India in the Himalayan foothills1. A fossil specimen from the late Miocene epoch of Lincang in Yunnan, Citrus linczangensis16, has traits that are characteristic of current major citrus groups, and provides definite evidence for the existence of a common Citrus ancestor within the Yunnan province approximately 8 million years ago (Ma).

Our analysis establishes a relatively rapid Asian radiation of citrus species in the late Miocene (6?8?Ma; Fig. 1c, d), a period coincident with an extensive weakening of monsoons and a pronounced climate transition from wet to drier conditions17. In southeast Asia, this marked climate alteration caused major changes in biota, including the migration of mammals18 and rapid radiation of various plant lineages19,20. Australian citrus species form a distinct clade that was proposed to be nested with citrons12, although distinct generic names (Eremocitrus and Microcitrus) were assigned in botanical classifications by Swingle1,5. Both molecular dating analysis21 and our whole-genome phylogenetic analysis do not support an Australian origin for citrus22. Rather, citrus species spread from southeast Asia to Australasia, probably via transoceanic dispersals. Our genomic analysis indicates that the Australian radiation occurred during the early Pliocene epoch, around 4?Ma. This is contemporaneous with other west-to-east angiosperm migrations from southeast Asia23,24, presumably taking advantage of the elevation of Malesia and Wallacea in the late Miocene and Pliocene25,26 (Supplementary Note 9).

The nuclear and chloroplast genome phylogenies indicate that there are three Australian species in our collection. One of the two Australian finger limes shows clear signs of admixture with round limes (Supplementary Note 5.4). The closest relative to Australian citrus is Fortunella, a species that has been reported to grow in the wild in southern China27. Australian citrus species are diverse, and found natively in both dry and rainforest environments in northeast Australia, depending on the species28. Our phylogeny shows that the progenitor citrus probably migrated across the Wallace line, a natural barrier for species dispersal from southeast Asia to Australasia, and later adapted to these diverse climates.

The results also show that the Tachibana mandarin, naturally found in Taiwan, the Ryukyu archipelago and Japan29, split from mainland Asian mandarins (Fig. 1c, d) during the early Pleistocene (around 2?Ma), a geological epoch with strong glacial maxima30. Tachibana, as did other flora and fauna in the region, very probably arrived in these islands from the adjacent mainland31 during the drop in the sea level of the South China Sea and the emergence of land bridges32,33, a process promoted by the expansion of ice sheets that repetitively occurred during glacial maxima (Supplementary Note 9).

Although Tachibana5,6 has been assigned its own species (Citrus tachibana), sequence analysis reveals that it has a close affinity to C. reticulata34,35 and does not support its taxonomic position as a separate species (Supplementary Note 4.1). However, both chloroplast genome phylogeny (Extended Data Fig. 1b) and nuclear genome clustering (Fig. 1a) clearly distinguish Tachibana from the mainland Asian mandarins. This suggests that Tachibana should be designated a subspecies of C. reticulata. By contrast, the wild Mangshan ‘mandarin’ (Citrus mangshanensis)7 represents a distinct species, with comparable distances to C. reticulata, pummelo and citron2 (Extended Data Table 1).
Pattern of pummelo admixture in the mandarins

Using 588,583 ancestry-informative single-nucleotide polymorphisms derived from three species, C. medica, C. maxima and C. reticulata, we delineate the segmental ancestry of 46 citrus accessions (Extended Data Fig. 2 and Supplementary Note 5). Pummelo admixture is found in all but 5 of the 28 sequenced mandarins, and the amount and pattern of pummelo admixture, as identified by phased pummelo haplotypes (Fig. 2a and Supplementary Note 6), suggests the classification of the mandarins into three types.

Figure 2: Admixture proportion and citrus genealogy.
a, Allelic proportion of five progenitor citrus species in 50 accessions. CI, C. medica; FO, Fortunella; MA, C. reticulata; MC, C. micrantha; PU, C. maxima; UNK, unknown. The pummelos and citrons represent pure citrus species, whereas in the heterogeneous set of mandarins, the degree of pummelo introgression subdivides the group into pure (type-1) and admixed (type-2 and -3) mandarins. Three-letter code as in Fig. 1, see Supplementary Table 2 for details. b, Genealogy of major citrus genotypes. The five progenitor species are shown at the top. Blue lines represent simple crosses between two parental genotypes, whereas red lines represent more complex processes involving multiple individuals, generations and/or backcrosses. Whereas type-1 mandarins are pure species, type-2 (early-admixture) mandarins contain a small amount of pummelo admixture that can be traced back to a common pummelo ancestor (with P1 or P2 haplotypes). Later, additional pummelo introgressions into type-2 mandarins gave rise to both type-3 (late-admixture) mandarins and sweet orange. Further breeding between sweet orange and mandarins or within late-admixture mandarins produced additional modern mandarins. Fruit images are not to scale and represent the most popular citrus types. See Supplementary Note 1.1 for nomenclature usage.

Type-1 mandarins represent pure C. reticulata with no evidence of interspecific admixture and include Tachibana, three unnamed Chinese mandarins (M01, M02, M04)3 and the ancient Chinese cultivar Sun Chu Sha Kat reported here, a small tart mandarin commonly grown in China and Japan, and also found in Assam. This cultivar is likely described in Han Yen-Chih’s ad 1178 monograph ‘Chü Lu’36, which includes references to citrus cultivated during the reign of Emperor Ta Yu (2205?2197 bc). Sixteen of the twenty-eight mandarins belong to type-2 mandarins, which have a small amount of pummelo admixture (1?10% of the length of the genetic map; Fig. 2a), usually in the form of a few short segments distributed across the genome. Although the lengths and locations of these admixed segments may be distinct in different mandarins, they share one or two common pummelo haplotypes (designated as P1 and P2) (Extended Data Fig. 3). By contrast, the seven remaining mandarins (type-3) contain higher proportions of pummelo alleles (12?38%; Fig. 2a) in longer segments. Although the P1 and P2 pummelo haplotypes are also detectable among type-3 mandarins, other more extensive pummelo haplotypes dominate the pummelo admixture in type-3 mandarins (Fig. 2b and Extended Data Table 2).

These observations suggest that the initial pummelo introgression into the mandarin gene pool may have involved as few as one pummelo tree (carrying both P1 and P2 haplotypes), the contribution of which was diluted by repeated backcrosses with mandarins (Supplementary Note 6.3). The introgressed pummelo haplotypes became widespread and gave rise to type-2 (early-admixture) mandarins (Fig. 2b). We propose that later, additional pummelo introgressions gave rise to type-3 (late-admixture) mandarins and sweet orange, and that some modern type-3 mandarins were derived from hybridizations among existing mandarins and sweet orange. This late-admixture model for type-3 mandarins is consistent with the historical records for Clementine and Kiyomi (both mandarin?sweet orange hybrids), and for W. Murcott, Wilking and Fallglo (hybrids involving other type-3 mandarins), whereas definitive records for the remaining two late-admixture mandarins (King and Satsuma) are not available.
 

大人の時間

 投稿者:  投稿日:2018年 2月 5日(月)13時38分1秒 KD182250243005.au-net.ne.jp
  大人の時間

子供は一週間たてば
一週間ぶん利口になる
子供は一週間のうちに
新しい言葉を五十覚える
子供は一週間で
自分を変えることができる
大人は一週間たっても
もとのまま

大人は一週間のあいだ
同じ週刊誌をひっくり返し
大人は一週間かかって
子供を叱ることができるだけ

谷川俊太郎
 

沖縄・奄美の言語、どう広がった? 琉球語の系統樹作成へ 狩俣琉大教授ら

 投稿者:  投稿日:2018年 2月 4日(日)23時59分12秒 KD182250243012.au-net.ne.jp
  http://www.okinawatimes.co.jp/articles/-/204534
 琉球大学・国際沖縄研究所の狩俣繁久教授らの研究グループが、琉球語を対象にした「言語系統樹」を作成する大規模な研究プロジェクトを進めている。琉球語が枝分かれした各地域方言間の影響や関係性を明らかにし、沖縄・奄美の言葉の複雑な相互関係の把握を目指す。系統樹で琉球語の広がり方を示すことによって、人や文化の動きも分析できるという。複層的な資料の解析、研究エリアが広範囲に及ぶ点など、関係者は「世界的にもまれな研究になる」と話している。(学芸部・与儀武秀)

 系統樹とは、さまざまな生物の時間的な変化を理解するため、類縁や分布の関係が示された樹木状の図。生物学で生き物の進化を把握する目的で作成されるほか、言語学でも用いられており、各言語の比較・検証が可能になる。

 昨年5月、文部科学省に約1億3千万円の研究費(2021年度までの5年間)が採択され、狩俣教授を代表者とする7人の研究グループが言語系統樹の作成を始めた。

 沖縄、宮古、八重山、奄美を含む琉球列島で調査された語彙(ごい)を基に(1)沖縄言語研究センターが調査した800地点200語(活用形含む350項目)(2)同センターの調査から選択した100地点1100語(3)これまでに刊行された奄美・沖縄各地の10冊の方言辞典-の3段階の系統樹作成に向け、データ入力や系統樹の試作などの作業を進めている。データベースに蓄積する語彙量も大幅に増やす。

 3段階の系統樹により単語数が増加し、より精密な系統樹が描けるため、単語や文法、発音などの相互関係や、言語の接触や分岐などの因果関係が理解できるようになるという。

 狩俣教授は「言語系統樹の研究はまだ十分ではないが、今回のように琉球弧の広い範囲で3段階の言語系統樹が作成されることは世界的にもまれだ」と指摘。「単語や文法、発音など、さまざまな系統樹を作成することが可能になり、より複雑な影響関係を把握することができる」と研究の意義を話している。

狩俣繁久教授らが作成した琉球語の言語系統樹
 

シジュウカラの音声言語、単語から指示対象をイメージする能力を確認

 投稿者:  投稿日:2018年 1月30日(火)15時53分39秒 KD182250243017.au-net.ne.jp
  シジュウカラの音声言語、単語から指示対象をイメージする能力を確認
http://www.kyoto-u.ac.jp/ja/research/research_results/2017/180130_1.html

2018年01月30日
 鈴木俊貴 生態学研究センター研究員は、野鳥の一種であるシジュウカラの研究を通して、単語からその指示対象をイメージする能力を、ヒト以外の動物において初めて明らかにしました。

 本研究成果は、2018年1月30日に米国科学アカデミー紀要(Proceedings of the National Academy of Sciences of the United States of America)にオンライン掲載されました。

研究者からのコメント
鈴木研究員
 従来、動物の音声コミュニケーションは、話し手が聞き手の行動を機械的に操作する単純なものであると考えられてきました。本研究は、この枠組みを覆しうる大きな成果です。「リンゴ」と聞くと赤いリンゴを頭に思い描くように、シジュウカラも「ヘビ」を示す鳴き声からヘビをイメージできるのです。私たちが会話の中で用いる様々な認知能力は、実は他の動物にも広く進化しているのかもしれません。

概要

 シジュウカラは天敵のヘビをみつけると、「ジャージャー」と聞こえる特別な鳴き声を発し、仲間に警戒を促します。この鳴き声は、ヘビに遭遇した時以外に発せられることがないので、「ヘビ」を示す単語(名詞)であるかもしれません。もしそうであれば、ヒトの言語と同様に、仲間のシジュウカラ(聞き手)にヘビのイメージを想起させる可能性があります。

 そこで本研究では、このヘビ特異的な鳴き声が、仲間のシジュウカラ(聞き手)にヘビに関する視覚イメージを想起させるかどうか実験的に検証しました。その結果、シジュウカラはこの声を聞いた時にだけ、ヘビのように木の幹や地面を這わせた小枝に接近し、それを確認することが分かりました。これはヘビ特異的な鳴き声からヘビの探索イメージを想起し、ヘビのように動く枝に当てはめた結果と考えられます。



図:ヘビ特異的な鳴き声を聞くと、木の幹(左)や地面(右)を這う枝をヘビだと勘違いして接近する

詳しい研究内容について

シジュウカラの音声言語、単語から指示対象をイメージする能力を確認
朝日新聞(1月30日 30面)、京都新聞(1月30日 27面)、産経新聞(1月30日 30面)に掲載およびNHK(1月30日)で放送されました。
 

スギの萌芽更新

 投稿者:  投稿日:2018年 1月30日(火)15時23分52秒 KD182250243017.au-net.ne.jp
  清水公社造林地内に見られる飯豊スギの萌芽更新について
https://www.jstage.jst.go.jp/article/jfsc/125/0/125_553/_article/-char/ja/
スギの萌芽更新は全国の多雪地帯などに点在して見られることが報告されている。また、スギが伏条して発根する特性をもつことも周知のことである。しかし、針葉樹は広葉樹に比べ萌芽しにくく、スギもその例外ではない。当林業公社会津事業所管内には、昭和40年代後期に前生樹の飯豊スギ(天然スギ)を含む皆伐跡地に新植した造林地がある。飯豊スギとは、飯豊山(標高2105m)の麓に位置する喜多方市山都町一ノ木地区・早稲谷地区に主に自生する天然スギを指して呼称している。新植して数年経過後、至る処の飯豊スギの伐根から数本にも及ぶ萌芽枝が発生していることを確認した。試行的に萌芽整理を行って今日に至っている林分があるが、林地には根茎から発生して成長したと思われるひこばえも多く混在し、新植した実生苗と萌芽枝の明確な区分が現在では困難な状況になっている。このため飯豊スギの萌芽発生が見られる現地に200㎡(20m×10m)のコドラートを設け、区域内全ての個体のDNA分析を行なってクローンと実生苗の区分を行うとともに、同一クローンの分布状況を識別した。

天然生スギ
http://kyoto-s-s.com/jyumoku-note/008/
京都の森林を見て一番驚いたことは、天然生の針葉樹それもスギがあることです。
それまで、スギは植えるもの、天然では屋久スギや秋田スギの一部ぐらいしかないと思っていました。

京都市の北部の山間地域には、峰床山(みねとこやま)や皆子山(みなごやま)など900mを超える山があります。
この地域は冬期に最低気温がマイナス10℃以下で積雪が100cmを超えることがあり、日本海型気候ともいえます。


天然生のスギは、花背や京北また広河原・久多などの中腹から尾根部にかけてみられます。

葉を握って大変痛い屋久スギとちがって、葉の形が雪を落としやすいよう細くて強い鎌状になったスギで、ウラスギと呼ばれます。

またこのスギは枝や幹から発芽する力が強く、また雪圧で地に付いた枝から発根し、新たな木となることができます。
これは伏状更新(ふくじょうこうしん)といわれます。

また幹を切ると、その脇からも発芽し、数本の幹が株立ちになることがあります。
これは萌芽更新(ほうがこうしん)といわれます。

その形から台杉(だいすぎ)とも呼ばれ、巨大なものは櫓杉(やぐらすぎ)とも呼ばれています。
櫓杉の分布では、特に花背の井ノ口から京北の片波にかけての峰は迫力ある伏状台スギの群落が見られます。

また花背の大悲山の国有林には「三本杉」と言われる樹高が60m近い府下で最高のみごとなスギがあります。


岐阜県関市の板取川上流『21世紀の森』に行ってきました。
http://jion-bee.cocolog-nifty.com/blog/2009/11/post-0701.html
『蕪山1069m』の登山口にもなっているところです。
目的は、登山ではなく『巨大株杉』。
 

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