五福花科花部维管结构的比较研究

首次报道了华福花属华福花 Sinadoxa corydalifolia和东方五福花 Adoxa orientalis花部维管结构,并对五福花科3属4种植物的花部维管系统进行了比较研究。3属4种的花部维管系统表现出不同的对称性和不同的复化、减化以及不同的融合程度。基于花部维管系统的证据,本工作支持四福花属四福花 Tetradoxa omeiensis为科内原始类群代表的看法。     

五福花科花部维管结构的比较研究

首次报道了华福花属华福花Ｓｉｎａｄｏｘａｃｏｒｙｄａｌｉｆｏｌｉａ和东方五福花Ａｄｏｘａｏｒｉｅｎｔａｌｉｓ花部维管结构,并对五福花科３属４种植物的花部维管系统进行了比较研究。３属４种的花部维管系统表现出不同的对称性和不同的复化、减化以及不同的融合程度。基于花部维管系统的证据,本工作支持四福花属四福花Ｔｅｔｒａｄｏｘａｏｍｅｉｅｎｓｉｓ为科内原始类群代表的看法。     

从ITS序列探讨青藏高原特有植物华福花属的亲缘关系

对青藏高原特有的濒危植物华福花（Ｓｉｎａｄｏｘａ ｃｏｒｙｄａｌｉｆｏｌｉａ Ｃ．Ｙ．Ｗｕ，Ｚ．Ｌ．Ｗｕ ｅｔ Ｒ．Ｆ．Ｈｕａｎｇ）的核糖体ＤＮＡ中的内转录间隔区（ＩＴＳ０序列及５．８ＳｒＲＮＡ基因的序列进行了测定。同川续断目和五加目有关类比较及分支分析表明华福花属与五福花属（Ａｄｏｘａ Ｌ．）近缘，不支持它可能与五加目或败酱科有亲缘关系的假设。尽管形态上它与五福花属分化十分明显，便ＩＴＳ碱基分     

狭义五福花科的分子系统学和物种分化

狭义五福花科(Adoxaceae.s.s)仅含3属4种,但该科的物种分化、系统发育和分类一直存在争议。本文通过测定东方五福花和血满草的ITS(核糖体DNA内转录间隔区)序列,构建了包括狭义五福花科(4种)、广义忍冬科接骨木属、荚属以及其余4属植物在内的系统发育树。研究结果不支持狭义五福花科内根据形态学证据做出的系统发育假设四福花不是该科中最早分化出来的种;该物种与五福花属的两个物种形成一个单系群,与另一分支华福花属相对应。该科中3个物种,四福花、五福花和华福花之间的分化主要是在二倍体水平上的异域分化,而东方五福花则是通过多倍化形成的。粗略的时间估算表明这些物种之间的分化较晚,可能在第三纪末至第四纪早中期,与青池高原近期强烈隆升以及冰期气候反复变化形成的环境变迁密切相关。     

五福花科花部形态的变异式样及其系统学意义

由于四福花Ｔｅｔｒａｄｏｘａ顶花、侧花均为典型的４数花,并被认为是科内最原始的属,因而长期以来关于五福花Ａｄｏｘａ“总苞一萼”还是“萼一花冠”的争议得到了彻底解决。根据本研究,五福花顶花和侧花的变异痃较五福花科另外３个分类群要高得多。五福花顶花和侧花的变异率分别为２０％和３６１％。通过后位雄蕊的退化和两则相邻花瓣的融合,雄蕊和花瓣从６数至３数的减少系列仅存在于五福花中。本文假设五福花科顶花和侧花的     

中国囊萼花属一新记录种——茎花囊萼花

首次报道了囊萼花属(Cyrtandromoea Zoll.)的1个中国新记录种——茎花囊萼花(Cyrtandromoea grandis Ridl.),该种原记载产于泰国、马来半岛和苏门答腊岛,2019年在中国云南省勐海县布朗山地区发现有分布。茎花囊萼花与囊萼花(Cyrtandromoea grandiflora C.B.Clarke)最为相似,但前者聚伞花序生于老茎上,每一花序3～18朵花,二者容易区别。     

高山植物花形态特征对花温度积累的影响

高山生态系统的低温环境不利于植物繁殖器官的发育和传粉过程,因此能改善花内或花序温度的结构对植物繁殖具有积极意义。该研究利用红外测温仪测量了高寒草甸中64种植物的花温度和叶温度以计算花温度积累,并检测了系统发育、花大小、花对称方式和花大小对花温度积累的影响。结果表明:所测量的64种植物种类,花部温度均高于叶部温度。花温度积累的系统发育信号较弱,表明物种间花温度积累的差异可能主要与不同物种对温度的需求有关。花温度积累与花大小存在显著的正相关关系,且两侧对称花的温度积累比辐射对称花更为迅速,但花对称方式和花颜色对花温度积累并没有显著的影响。该研究结果表明花温度积累在不同植物间存在很大的差异,但这些差异对植物繁殖的实际贡献和意义仍需要进一步验证。     

中国叉柱花属(爵床科)二新记录种————中越叉柱花、密花叉柱花

确定爵床科Acanthaceae叉柱花属Staurogyne的中越叉柱花S. petelotii Benoist和密花叉柱花S. vicina Benoist为中国新记录。     

多花菜豆和蚕豆花的冗余与适应

采用人工干扰方法,探讨多花菜豆和蚕豆花的冗余及其对不可测干扰的适应。结果表明,多花菜豆和蚕豆的花序、花的时间冗余和花的数量冗余,保证了总有一部分花序和花能避开外界因子的干扰而结荚。多花菜豆受干扰与未受干扰(对照)植株的花有效率均为2．2％;而受干扰植株的花序有效率为29．0％,比对照(15．9％)增加近1倍。对蚕豆连续摘除开放的花朵和连续摘除嫩荚这两种处理与对照的单株平均结荚数十分接近。分别为3．2、3．1和3．1。多花菜豆花序上部的花和蚕豆花序中较小的花常常凋落不结实,表现出花的自疏现象,所谓的无效花,但当分别只保留上部花和小花时,它们即可成为结荚的有效花。另外,研究表明,即使给多花菜豆和蚕豆提供充足的养分,每个花序的平均结荚数并无明显增加,说明养分不是产生大量无效花的主要原因。多花菜豆和蚕豆所开的大量花是一种备用。不是多余的或可有可无的,是对付外界随机干扰的一种适应;其花序和花的时间冗余以及花的数量冗余在个体繁殖和物种延续中起着关键性作用。     

植物花发育的分子机理研究进展

花的发育分为开花决定、花的发端和花器官的发育三个阶段。植物开花由多条途径诱导,包括光周期和光质诱导、春化作用、自主途径、赤霉素诱导、碳水化合物诱导等;植物体本身也存在着开花抑制途径。各种开花诱导途径能激活花分生组织特性基因,使茎端分生组织转变为花分生组织。花器官的发育由器官特性基因决定,这些基因的精确表达需要花分生组织特性基因的激活和多个正、负调节因子的调控;另有一类基因控制着花发育的对称性。花发育机理的研究具有重要的理论意义和广泛的应用前景。     

On the ecological and evolutionary significance of storage in clonal plants

Environmental heterogeneity has received wide attention in clonal plant research over the last decade. Most studies have focussed on the effects of spatial variation in environmental conditions on the performance of ramets and genets, while the effects of temporal heterogeneity have only occasionally been studied. As a consequence, our current knowledge about functional responses of clonal plants to habitat patchiness is biased towards spatial aspects of environmental heterogeneity. Nevertheless, temporal changes in biotic and abiotic conditions do occur in most natural habitats, and they are very likely to affect plant growth and performance, and to create positive selection pressures on traits that can buffer plants against unfavorable consequences of this variability. Storage of resources is a widespread phenomenon in clonal plant species. Typical clonal structures such as stolons, rhizomes and hibernacles serve as storage organs. However, the ecologic significance of storage in clonal plant structures remains partly unclear. We suggest that the lack of understanding with respect to resource storage in clonal plants be related to our poor knowledge of ecologic implications of temporal habitat heterogeneity in natural environments. Resource storage can be understood as a safety measure against temporal changes in the growing conditions of plants. This paper summarizes existing information about the ecologic relevance of storage in clonal plants and it tries to develop a framework for further investigation of resource storage as a strategy to enhance the performance of clonal plants in temporally variable environments.     

两种作物套种生态系统动态模型的建立及分析

本文主要建立小麦、大豆两种作物套种共生生态系统的Volterra方程模型．分析该模型得知,此生态系统是相互竞争的,其自身增长率因环境因素而受抑制,且是全局稳定的．其次计算出该生态系统在平衡状态处受到标准扰动之后,向平衡状态恢复的时间,有利套种作物生长的调控。     

Role of Salix reinii patches in spatio-temporal patterns of cohabitants on a Japanese volcano

深山柳斑块在日本火山共栖物种时空格局中的作用 灌木斑块通常能为定植物种提供支持，尤其是在具有压力和/或干扰的环境中，这种作用更明显。山地上的压力和干扰强度通常与海拔梯度有关，并会因灌木斑块(树冠和凋落物)而降低。本研究旨在利用火山上不同海拔高度的灌木斑块来阐明这些关系。从2005年早春到2006年夏季，我们在日本北部高丽山(海拔1131 m)的3个海拔高度监测了深山柳(Salix reinii)斑块内外所有地块中的所有嫩枝及其相关 环境，例如温度、光照、湿度和化学成分。我们通过面积、分枝密度和凋落物厚度对斑块结构进行评价。研究结果表明，灌木斑块的结构在不同海拔之间并无差异。通过在整体上增加植物物种的丰富度，这些斑块提高了稀有物种的多样性。斑块内的水分、氮和磷含量均要高于斑块外。灌木斑块对于共栖物种的影响总体上是正向的，但对幼苗丰度、嫩枝存活率和开花的影响则是负面的。这些结果表明灌木斑块的生长格局决定了植物群落结构，并促成了植物的多样性。     

NLR及其在植物抗病中的调控作用

为适应丰富多变的生存环境, 植物逐渐进化出一套复杂的免疫系统来抵抗病原菌的侵染。核苷酸结合的富含亮氨酸重复蛋白(NLR)作为植物体内普遍存在的一类抗性(R)蛋白, 对植物的抗病性具有重要调控作用。该文综述了NLR蛋白结构、信号转导以及对植物抗病的调控作用近几年的研究进展。     

Roots,nutrients and their relationship to spatial patterns

Ecosystem sustainability and resilience after a disturbance may be regulated by processes occurring at smaller spatial scales. The matrix of different spatial environments are created by (1) individual plants that accumulate higher concentrations of specific nutrients, trace elements or defensive plant secondary chemicals and thereby modify the chemistry of their ecological space and/or rates of processes, (2) the presence of structures (e.g., coarse woody debris) that may buffer some micro-environments from disturbances by functioning as a hospitable environment or as a reservoir for mycorrhizal fungi to sustain them into the next phase of stand development, and (3) chemical changes in soils during soil development which may result in distinct soil chemical environments. The response of the plants or change in the sustainability of carbon and nutrient cycles may be expressed more strongly at this smaller ecological space of an individual plant and furthermore must be frequently examined separately by the above- and belowground space of that individual.This paper will present three case studies from temperate and tropical forest ecosystems which suggest the importance of studying plant growth and nutrient and trace element cycling by stratifying sampling to encompass the mosaic patterns of existing spatial variability within the ecosystem. The examples show how individual plant species are able to create ecologically distinct spatial environments because of their distribution patterns within the landscape, how nutrient transfers in roots respond to the chemical variations in the soil, and how roots and mycorrhizal fungi are able to maintain themselves in the mosaic of coarse woody debris remaining on a site after the elimination of aboveground tree biomass.     

Ostracod range charts as a chronoecologic tool

Using a linear time scale and equating the durations of species with those of their ecologic niches, range charts of ostracods show ecologic events. As a non-marine example, the Upper Miocene record of the genusCyprideis shows asymptotic freshening of the Central Paratethys. Duration charts of British Jurassic and Cretaceous shallow marine species reflect shore-line movements which generally do, but sometimes do not correlate with global sea-level changes.Charts of all (marine and non-marine) ostracod species distinguish regressions due to progradation during a sea-level rise or highstand from those caused by falling sea-level.Global sea-level changes not only directly induce large-scale creation and destruction of shallow-water benthic niches, but also will drastically affect pelagic and terrestrial environments. The ostracod record discussed in this paper suggests that eustacy is an important driving force behind macroevolution.     

Drought-Tolerance of Wheat Improved by Rhizosphere Bacteria from Harsh Environments: Enhanced Biomass Production and Reduced Emissions of Stress Volatiles

Water is the key resource limiting world agricultural production. Although an impressive number of research reports have been published on plant drought tolerance enhancement via genetic modifications during the last few years, progress has been slower than expected. We suggest a feasible alternative strategy by application of rhizospheric bacteria coevolved with plant roots in harsh environments over millions of years, and harboring adaptive traits improving plant fitness under biotic and abiotic stresses. We show the effect of bacterial priming on wheat drought stress tolerance enhancement, resulting in up to 78% greater plant biomass and five-fold higher survivorship under severe drought. We monitored emissions of seven stress-related volatiles from bacterially-primed drought-stressed wheat seedlings, and demonstrated that three of these volatiles are likely promising candidates for a rapid non-invasive technique to assess crop drought stress and its mitigation in early phases of stress development. We conclude that gauging stress by elicited volatiles provides an effectual platform for rapid screening of potent bacterial strains and that priming with isolates of rhizospheric bacteria from harsh environments is a promising, novel way to improve plant water use efficiency. These new advancements importantly contribute towards solving food security issues in changing climates.     

生态恢复中灌丛保育效应研究进展

灌木作为干旱半干旱地区植被的主要组成部分,对于维持生态系统稳定性和发挥生态服务功能具有重要作用。灌丛保育效应可以减轻限制性因子对目标植物生长和繁殖的不利影响,促进退化生境植物物种自然更新和植被恢复。本文综述了近20年有关灌丛保育效应研究和应用的主要成果,从微生境改善、肥岛形成、防御和抵抗作用发挥、有益微生物引入和协助繁殖体传播或保存以及种间竞争网络格局改变等方面阐述灌丛保育效应的促进机制,并从非生物环境、生物干扰、生活史阶段和生长繁殖策略等方面分析影响灌丛保育效应发挥的关键因素。从完善灌丛保育效应的理论机制和开展多因素共同作用下多植物物种相互作用关系模型构建角度,对灌丛保育效应的研究进行了展望。     

Time allocation of a parasitoid foraging in heterogeneous vegetation: implications for host-parasitoid interactions

1. Changing plant composition in a community can have profound consequences for herbivore and parasitoid population dynamics. To understand such effects, studies are needed that unravel the underlying behavioural decisions determining the responses of parasitoids to complex habitats. 2. The searching behaviour of the parasitoid Diadegma semiclausum was followed in environments with different plant species composition. In the middle of these environments, two Brassica oleracea plants infested by the host Plutella xylostella were placed. The control set-up contained B. oleracea plants only. In the more complex set-ups, B. oleracea plants were interspersed by either Sinapis alba or Hordeum vulgare. 3. Parasitoids did not find the first host-infested plant with the same speed in the different environments. Sinapis alba plants were preferentially searched by parasitoids, resulting in fewer initial host encounters, possibly creating a dynamic enemy-free space for the host on adjacent B. oleracea plants. In set-ups with H. vulgare, also, fewer initial host encounters were found, but in this case plant structure was more likely than infochemicals to interfere with the searching behaviour of parasitoids. 4. On discovering a host-infested plant, parasitoids located the second host-infested plant with equal speed, demonstrating the effect of experience on time allocation. Further encounters with host-infested plants that had already been visited decreased residence times and increased the tendency to leave the environment. 5. Due to the intensive search of S. alba plants, hosts were encountered at lower rates here than in the other set-ups. However, because parasitoids left the set-up with S. alba last, the same number of hosts were encountered as in the other treatments. 6. Plant composition of a community influences the distribution of parasitoid attacks via its effects on arrival and leaving tendencies. Foraging experiences can reduce or increase the importance of enemy-free space for hosts on less attractive plants.     

Canopy Openness Enhances Diversity of Ant–Plant Interactions in the Brazilian Amazon Rain Forest

In closed‐canopy tropical forest understory, light availability is a significant determinant of habitat diversity because canopy structure is highly variable in most tropical forests. Consequently, variation in canopy cover affects the composition and distribution of plant species via creating variable light environments. Nevertheless, little is known about how variation in canopy openness structures patterns of plant–animal interactions. Because of the great diversity and dominance of ants in tropical environments, we used ant–plant interactions as a focal network to evaluate how variation in canopy cover influences patterns of plant–insect interactions in the Brazilian Amazon rain forest. We observed that small increases in canopy openness are associated with increased diversity of ant–plant interactions in our study area, and this change is independent of plant or ant species richness. Additionally, we found smaller niche overlap for both ants and plants associated with greater canopy openness. We hypothesize that enhanced light availability increases the breadth of ant foraging sources because variation in light availability gives rise to plant resources of different quality and amounts. Moreover, greater light availability promotes vegetative growth in plants, creating ant foraging ‘bridges’ between plants. In sum, our results highlight the importance of environmental heterogeneity as a determinant of ant–plant interaction diversity in tropical environments.