【作者】 张建民；

【导师】 常杰； 葛滢；

【作者基本信息】 浙江大学 ， 生态学， 2008， 博士

【摘要】 石荠芋属（Mosla（Benth.）Buch-Hamilt.Ex Maxim.）是唇形科的一个小属,分布区西起西喜马拉雅山,东到日本,北至俄罗斯远东,南至印度尼西亚。该属物种的形成方式一直是关注的问题。本文是对该属进行了三年的生态分化的1研究结果。进行了广泛的野外调查后,选取了36个样地进行取样和参数测定;在控制环境因素的实验设计条件下,我们进行了土壤水分、光照强度和氮形态比例的可控实验研究,分别测定了石荠芋属7个物种的形态、解剖、生理和生长等方面的参数。综合上述各方面资料的分析结果,对石荠芋属生境分化、生态分化的主要性状特征、物种形成以及该属各物种在未来气候变化下的适应能力作了详细的分析和探讨。1)石荠芋属7个物种在中国的分布是沿着环境梯度而分布的,它们的表型特化有助于解释这些物种共存于一些生境,而不象预期的那样由于竞争而相互排斥。野外生境调查研究表明,石荠芋属7个物种都有各自的现实生态位,主要表现在生境的土壤水分、光照、土壤质地和土壤营养。在每一环境梯度下,各物种的生态幅是不同的。有些物种很少与别的物种共存于同一样地,而有些物种常常共存于同一样地,尽管样地间的丰富度有明显差别。2)土壤水分和光照强度的可控实验表明,该属物种响应不同水分和光强的主要的生态分化表现在形态和生理特征性状上。这些都有力的支持,石荠芋属物种沿着环境梯度的分布不是偶然的,许多功能特征都与从性状功能所预测的物种分布相符合。在系统进化上,物种在功能和生境偏好上的进化趋于一致。相反,叶片水平的结构特征在系统进化上是较保守的,与微生境的关联不紧密,而与大的地理分布区相关。3)人类的农业活动强烈干扰氮素循环,特别是在近几十年内,氮的输入增加了两倍多。过量氮的输入改变生物多样性、生态系统的初级生产力和养分循环、氮素转换和损失的速度、增加温室气体（CH₄和NO₂等）排放、加速土壤酸化和水酸化、甚至导致森林衰退等。为了探究不同氮素形态对石荠芋属物种的影响,我们进行了氮素形态不同比例的实验。石荠芋属物种对不同氮形态比例的响应各异。在不同氮形态比例下,石荠芋属物种表现出在形态、生理和生长特性上的明显分化,它们的相对生长速率与它们各自的功能特性相一致。疏花荠芋（Mosla pauciflora）在全铵态氮比例下可以存活,且它在高的铵态氮比例下有最大的相对生长速率。这表明疏花荠芋能够适应未来高比例的铵态氮的环境。而石荠芋属其他5个物种在高比例的铵态氮条件下,生长速率明显降低,并在功能特征上表现出明显的铵中毒症状,如叶片卷曲,发黄,枯萎,叶绿素含量降低等。这些显示这五个物种不能适应未来高比例的铵态氮的环境。更多还原

【Abstract】 Mosla (Benth.) Buch.-Hamilt. Ex Maxim. is a small genus (Lamiaceae) ranging from the west-Himalayas eastwards to Japan, and from the Far East of Russia southwards to Indonesia. Its speciation patterns are the key objective. The present dissertation reports the results of three-year-period ecological differentiation studies on this genus. Intensive field surveys and observation were conducted and thereafter 36 plots were sampled. The common garden experiment was made, and control experiments of soil water availability, light intensity and different nitrogen forms were made. Morphological, anatomical, physiological traits and biomass yield of seven Mosla species were measured. Based on all results, the habitat differentiation patterns, the major functional traits of ecological differentiation, adaptive capability of future climate changes, and speciation patterns were investigated in detail.1) Differentiations of species distributions along environmental gradients and phenotypic specialization help explain the co-presence of seven Mosla species that might otherwise be expected to competitively exclude one another. Field investigation results showed each of the seven species appeared to have a unique realized niche, when niche dimensions were defined by soil moisture, gradients in soil texture, soil fertility and light. The species also differed in how broadly or narrowly they were distributed along each gradient. Some species were practically never found in the same sites, whereas others co-occurred with a high frequency, in spite of showing clearly different abundance patterns among sites. 2) The data of control experiments of soil water availability and light intensity show significant morphological and physiological differentiation among the closely related species of Mosla. There is clear evidence for ecological sorting among the Mosla species as species partition environmental gradients more than expected by chance, and most functional traits of species correspond to species distributions as predicted based on a priori understanding of trait function. Across phylogenetic lineages, species showed evolutionary convergence in function and habitat preference. By contrast, leaf-level traits were conserved within phylogenetic lineages and were not well correlated with local habitat factors, but rather with the broader geographic distributions.3) Human intervention in the nitrogen cycle is presently adding more reduced nitrogen to the biosphere as the result of intensive agricultural activities. N input has more than doubled since the 1950s in many areas. This additional N input has led to the N saturation of many natural ecosystems and has affected species composition, forest contraction, while phenomena as important as large-scale forest decline have been linked to anthropogenic NH4~+ input and associated soil acidification. In order to determine the effects of nitrogen forms on Mosla species, the control experiment of different proportion of nitrogen forms was conducted. Mosla species had different response to different proportion of nitrogen forms. With the treatment of different proportion of nitrogen forms, morphological, physiological and growth characteristics of Mosla species differentiated. And species RGR (relative growth rate) were well correlated with their function traits. Mosla pauciflora can survive from complete ammoniac nitrogen form treatment, and RGR was great with the high proportion of ammoniac nitrogen form treatment. Form this we can see that Mosla pauciflora can well adapt the future environment of high ammoniac nitrogen. However, other five species showed evident symptoms of NH4~+ toxicity (eg: the chlorosis of leaves and the overall suppression of growth and so on) with high proportion of ammoniac nitrogen form treatment. These data show the other five Mosla species can not well adapt the future environment of high ammoniac nitrogen.更多还原