植物的亲缘选择

Kin selection in plants

亲缘选择是指在一个随机交配群体中的个体基于亲缘关系而以一种非随机性的方式相互作用,其作用结果是亲缘个体得到更大的广义适合度。综述了亲缘选择和亲缘竞争两种观点以及各自的试验支持证据;分析了导致亲缘选择试验结果出现分歧的原因,认为这主要是由于对亲缘选择理解上的模糊以及试验设计的不严谨所致。植物间的亲缘选择研究不仅相对较少,对亲缘选择的机制研究更为欠缺,这就造成了目前对此问题在科学认识上出现不少盲点。综合前期研究,提出今后对亲缘选择的研究应该首先界定"亲缘"程度,同时改良试验设计方案,选择多种不同生境下的物种对亲缘选择进行深入研究,并且考虑环境因子对植物亲缘选择的影响。同时,对植物亲缘识别机制的研究应该从生理生化方面出发,通过定性定量地分析探索植物根系分泌物在植物亲缘识别中的作用和作用途径。

Kin selection is an evolutionary strategy that favors the reproductive success of an organism＇s relatives, even at a cost to the organism＇s own survival and reproduction. It is also defined as random mating of individuals genetically closely-related, through their interactions, to make them fit. Although kin selection is universally authenticated among animals, studies of kin selection in plants are scanty, and available sources are inconsistent. In this article we reviewed the available documents on kin selection and niche partition, brought supporting evidences and discuss reasons for differences in experimental results, come up with possible mechanisms of kin selection for future research. The theory of ecological niche partition stipulates that given interactions between kin plants, there is ＂kin competition＂ as well as ＂kin cooperation＂ in consistent with kin selection. Recent studies on kin selection in plants have shown that plants increased their root allocation when groups of strangers shared a common pot compared to groups of siblings, which indicates plants may discriminate kin under competitive conditions and benefit their siblings. Contrary to this, other studies have proved that it was not kin selection, but the competition ability of plants that predicts interaction results. Such opposite conclusions are mainly attributed due to two reasons：1） Different species have different ability of kin selection or niche partition. Species which have stronger ability of kin selection benefit siblings on fitness; while other species have stronger ability of niche partition will benefit strangers. 2） Improper experimental design resulting mislead deduction, such as without considering the effects of different families that have different competition abilities, wrong indexes irrelevant to fitness and neglecting effects of soil volume. Because of insufficient previous researches on kin selection, it is impossible to make confirmative conclusions on whether kin selection commonly exists in plants. Mechanisms of kin selection may rely mainly on roots. Studies have shown that roots are the transmission channels for kin signals because kin selection occurs only when neighbor roots appears nearby. Other studies reported that related plants transmit genetic information through root secretion among each other. It is also possible that microbes are drivers of intra-specific processes to favor sibling or stranger groups, but so far convincing evidences are rare. Undoubtedly, there is a need to focus on observation and analysis of root system to correlate between roots and kin selection for in-depth studies on kin selection mechanism. Therefore proper research inconsideration to all the parameters explaining the kin selection are required to arrive in conclusion. Through the literature review, it is apparent that for the detailed understanding of kin selection in plants, we need to improve experimental designs by choosing multiple families of species under different environmental conditions to conduct thorough studies and determine universality of kin selection among plant species. To explore mechanisms of kin selection in plants, physiological and biochemical studies are also required to ascertain plants secretions and exudates in recognizing their kin and determine their secretions pathways, explore how signal（s） are generated, transmitted and effects on kin relationships by the method of signal transduction.