近期，中科院华南植物园科学家研究发现系统发育对植物元素含量的影响。研究成果在线发表于《机能生态学》上。

据介绍，阐明植物元素含量特征及其影响因子，对于理解植物对环境变化的响应与适应具有重要意义。华南植物园的科研人员通过对华南苦苣苔科植物叶片及其对应土壤元素含量特征分析，在系统发育的框架下，研究了系统发育、土壤和气候条件对植物元素含量的影响及元素之间的互作关系。

他们发现在苦苣苔科的水平上，叶片元素含量具有强烈的系统发育信号（或系统发育生态位保守性）；而在报春苣苔属的水平上，叶片元素含量没有明显的信号。此外，该研究还揭示华南苦苣苔科植物在科的水平上具有强烈的土壤和气候系统发育生态位保守性，而在报春苣苔属水平上大部分土壤因子没有系统发育生态位保守性，但气候因子具有系统发育生态位保守性。

据悉，该研究首次同时定量估测了系统发育、土壤和气候条件对植物叶片元素含量的影响，研究结果暗示在考察环境因子对植物元素含量影响的时候，需要考虑系统发育背景，即进行系统发育独立性比较。（来源：中国科学报 李洁尉）

Floral ecology of Oreocharis pumila (Gesneriaceae):

a novel case of sigmoid corolla

Abstract  Attraction of pollinators and successful pollen transfer represent the primary targets of selection during flower evolution, leading to repeated evolutionary shifts between pollinators and consequently to the diversification of floral forms. However, most studies in floral evolution focus on the characteristics of flowers with straight corolla tube. Here, we report on an unusual form of sigmoid corolla combined with protandry and herkogamy in a Chinese species of Gesneriaceae, Oreocharis pumila (formerly Opithandra pumila). Contrary to species with sigmoid corollas studied previously, the base of the corolla tube of this species is inclined at an oblique angle downwards before the tube bends forward, and the stigma and anthers are included in the upper part of the corolla tube. The plants were found to be self-compatible but incapable of autonomous selfing. Successful pollination was found to depend fully on the presence of insect pollinators (Nomia sp.) and pollen grains are the greatest reward for the visitors. Different from the other sigmoid flowers, the sigmoid corolla of O. pumila was not found to favor insect pollinators with long flexible proboscises. A mechanical fit between floral morphology and pollinator was found, in which only small insect visitors with specialized visiting behavior are legitimate pollinators. The protandry combined with herkogamy in the sigmoid corolla tube strongly ensures pollination efficiencies. Oreocharis pumila is the only species with sigmoid corolla in the genus Oreocharis. We hypothesize that such a corolla has arisen through selection due to inadequate pollination in early spring in the mountainous habitat that O. pumila occupies.

原文链接：http://onlinelibrary.wiley.com/doi/10.1111/j.1756-1051.2013.00105.x/pdf