物候研究的论文

物候研究的论文

立春过后，大地渐渐从沉睡中苏醒过来。冰雪融化，草木萌发，各种花次第开放。再
过两个月，燕子翩然归来，不久，布谷鸟也来了。于是转入炎热的夏季，这是植物孕育果实
的时期。到了秋天，果实成熟，植物的叶子渐渐变黄，在秋风中簌簌的落下来。北雁南飞，
活跃在田间草际的昆虫也都销声匿迹。到处呈现一片衰草连天的景象，准备迎接风雪载途的寒冬。在地球上温带和亚热带区域里，年年如是，周而复始。
几千年来，劳动人民注意了草木荣枯、候鸟去来等自然现象同气候的关系，据以安排农事。杏花开了，就好像大自然在传语要赶快耕地；桃花开了，又好像在暗示要赶快种谷子。布谷鸟开始唱歌，劳动人民懂得它在唱什么：“阿公阿婆，割麦插禾。”这样看来，花香鸟语，草长莺飞，都是大自然的语言。
这些自然现象，我国古代劳动人民称它为物候。物候知识在我国起源很早。古代流传下来的许多农谚就包含了丰富的物候知识。到了近代，利用物候知识来研究农业生产，已经发展为一门科学，就是物候学。物候学记录植物的生长荣枯，动物的养育往来，如桃花开、燕子来等自然现象，从而了解随着时节推移的气候变化和这种变化对动植物的影响。

帮忙写一个关于气候变暖的论文

气候变暖对陆地生态系统的影响*
吴　循1,
2　周　青1,
2**
(1.江南大学工业生物技术教育部重点实验室　无锡　214122;
2.江南大学生物科学系　无锡　214122)
摘　要　人类活动引起的温室效应导致全球气候变暖,气候变暖对全球生态环境的影响越来越受到人们的关
注。作为人类赖以生存的环境主体,陆地生态系统对气候变暖将做出何种响应,更是人们关注的重点。植物
物候的变化可以直观地反映某些气候变化,尤其是气候变暖。气候变暖影响植物的生长节律,进而引起植物
与环境关系的改变及生态系统物质循环(如水和碳的循环)的改变。不同种类植物对气候变化的差异响应,会
使植物间和动植物间的竞争与依赖关系发生深刻的变化,如北半球中高纬度地区植被生长季延长、植物提早
开花、昆虫提早出现、鸟类提早产蛋以及冰川退缩、永冻土带融化、江河湖泊结冰推迟而融化提早等。本文主
要从陆地生态系统的分布和演替两方面着眼,以植物和动物作为考察对象,系统论述了森林、草原、荒漠、湿地
及农田等陆地生态系统在气候变暖背景下产生的变化,并从微观和宏观尺度上提出陆地生态系统变化的生态
学机制,最后在技术和政策层面给出若干对策。
关键词　气候变暖　陆地生态系统　分布　演替　机制　对策

找一篇已经发表过的植物物候的英文论文

题目
The role of tree size in the leafing phenology of a seasonally dry tropical forest in Belize, Central America

摘要
Abstract. Leafing phenology of two dry-forest sites on soils of different depth (S = shallow, D = deep) at Shipstern Reserve, Belize, were compared at the start of the rainy season (April–June 2000). Trees _ 2.5 cm dbh were recorded weekly for 8 wk in three 0.04-ha plots per site. Ten species were analysed individually for their phenological patterns, of which the three most common were Bursera simaruba, Metopium brownei and Jatropha gaumeri. Trees were divided into those in the canopy (> 10 cm dbh) and the subcanopy (_ 10 cm dbh). Site S had larger trees on average than site D. The proportion of trees flushing leaves at any one time was generally higher in site S than in site D, for both canopy and subcanopy trees. Leaf flush started 2 wk earlier in site S than site Dfor subcanopy trees, but only 0.5 wk earlier for the canopy trees. Leaf flush duration was 1.5 wk longer in site S than site D. Large trees in the subcanopy flushed leaves earlier than small ones at both sites but in the canopy just at site D. Large trees flushed leaves earlier than small ones in three species and small trees flushed leaves more rapidly in two species. Bursera and Jatropha followed the general trends but Metopium, with larger trees in site Dthan site S, showed the converse with onset of flushing 1 wk earlier in site Dthan site S. Differences in response of the canopy and subcanopy trees on each site can be accounted for by the predominance of spring-flushing or stem-succulent species in site S and a tendency for evergreen species to occur in site D. Early flushing of relatively larger trees in site D most likely requires access to deeper soil water reserves but small and large trees utilize stored tree water in site S.

关键词
Key Words: hardwood trees, leaf flush, onset, sampling interval, soil depth, spring-flushing trees, tree size

简介
INTRODUCTION
Although water is the limiting factor for part of the year in seasonally dry tropical forests, many tree species flush their leaves during the dry season, before the onset of the rains (Bullock & Solis-Magallanes 1990, Mooney et al. 1995). Two principal reasons for this have been suggested: (1) new leaves may be able to make maximum
use of the higher radiation during the dry season (Wright & van Schaik 1994); and (2) new leaves avoid predation when herbivores are at their least abundant in
the dry season (Murali & Sukumar 1993). Selection would be expected to operate in favour of early leaf flushing, i.e. before the start of the rainy season.
Climatic factors alone are often not sufficient to explain phenological variation in tropical dry forests (Borchert 1994a). Water stored in the tree stem, or remaining in the subsoil, buffers the impact of low water availability and allows the production of new leaves during the dry season (Borchert 1980, 1983, 1994a, b; Reich & Borchert 1984). This indicates that tree water status, rather than climatic factors directly, is probably the principal determinant of tree phenology in the seasonally dry tropics.
Borchert & Rivera (2001) have shown that leaf buds remain dormant during the dry season in many tree species of semi-deciduous tropical forests, and bud-break is induced by an increasing photoperiod after the spring equinox. Bud-break is highly synchronous in conspecifics of these ‘spring-flushing’ trees, although some withinspecies differences occurred. One likely explanation for the latter is the amount of stem-, soil- or rain-water available to the tree. Whether leaf flush is triggered by photoperiod or other factors, sufficient water supply is a prerequisite. Bud-break and leaf expansion during the dry season occur only when the trees are fully rehydrated
(Borchert 1994a, b; Borchert et al. 2002). The rate of shoot development and the duration of leaf expansion varies strongly with water availability (Borchert 1994b,
Borchert & Rivera 2001).

竺可桢在气候研究方面有什么成就?

学术成就有：1961年他撰写了《历史时代世界气候的波动》，1972年他又发表了《中国近五千年来气候变迁的初步研究》等学术论文。前者依据北冰洋海冰衰减、苏联冻土带南界北移、世界高山冰川后退、海面上升等有关文献资料记述的地理现象，证明了二十世纪气候逐步转暖，并由此追溯了历史时期和第四纪世界气候、各国水旱寒暖转变波动的历程，发现十七世纪后半期长江下游的寒冷时期与西欧的“小冰期”相一致。最后指出：太阳辐射强度的变化，可能是引起气候波动的一个重要原因。从而为历史气候的研究提供了新的论据。后一篇论文，可说是他数十年深入研究历史气候的心血的结晶，是一项震动国内外的重大学术成就，他充分利用了我国古代典籍与方志的记载，以及考古的成果、物候观测和仪器记录资料，进行去粗取精、去伪存真的研究，得出了令人信服的结论。
　 在气象科学研究中，竺可桢一向十分重视气象气候与生产及人类生活的联系。早在1922年，他就发表过《气象学与农业之关系》的学术论文。1964年他又发表了《中国气候特点及其粮食作物生产的关系》，他运用植物学的原理，以太阳辐射总量、温度、雨量三个气候要素为依据，分析了我国气候的特点，气候与农作物生产的关系，论述了我国粮食作物在各地区发展的潜力及限度，为改革栽培制度提出了方向性的意见。这篇论文，受到学术界的高度重视，竺可桢也因之受到毛泽东主席的接见。
　　竺可桢又是我国物候学研究的创始者。他从1921年起就观察记录物候。1963年和宛敏渭合著《物候学》出版。内容丰富，文字通俗，，普及了物候学知识，提倡因地制宜，利用物候规律安排农事活动。此书一出就迅速销售一空。
　　竺可桢也是我国现代物候学发展的推动者，物候学是他呕心沥血做出了重要贡献的领域之一。我国现代物候学的每一成就都是和他的工作分不开的。
　　他是我国现代物候观测网的倡导者和组织者。组织起统一的、严格的物候观测网，是现代物候学发展的重要标志。
还望采纳。