The effects of activated carbon and plants diversity ... - 华南农业大学

华 南 农 业 大 学 农 学 院 第 三 届 综 述 大 赛 获 奖 作 品 论 文 集一 等 奖 作 品other ecologically sound processe, or, species diversity may contribute in some way to theautotoxicity.So there are researchers hypothesize that if there are any advantages for plants when theeffects of allelopathy from different plants emerge on successive generations. In other words,does autotoxicity in plants have an ecological significance or does allelopathy in differentsub-dominatn species have an ecological positive feedback on autotoxicity of plants? Severalauthors believe that autotoxicity may play a prime role as population regulator, and inaccordance with an ecological point of view, autotoxicity is an interesting mechanism.Canals (2005) analysed the autoxitic phenomenon in Lolium rigidum, and hypothesizedthat autotoxicity enhance population viability by restraining the development of populationswith few individuals, which should decrease the chances of outcross and experience inbreedingdepression (Canals et al. 2005). Mazzoleni propose that autotoxicity is a general phenomenon,and stronger than phytotoxic effects on other species, thus largely affecting ecosystem stability,productivity and diversity (Mazzoleni et al. 2007). An important consequence of theoccurrences of autotoxic induced negative feedback on conspecific is the reduction ofindividual’s vigor and dominance over more competitive species, in favor of other species, thusenhancing coexistence. Model studies implemented these concepts and demonstrated hownegative feedback can affect both the spatial organization and the species diversity of plantcommunities(Bever 1994; Bonanomi et al. 2005).As we knew, genetic variation in competitive ability has been proposed to promotespecies coexistence in many systems. However, some traits involved in non-resource-basedcompetition may have opposing effects on intra- and interspecific competitive ability (Lankau2008). Lankau suggested that, genotypes that invest heavily in a toxic allelochemical wouldbe strong interspecific competitors, but may be weak competitors against their own species(which is unaffected by the chemical) if expressing the trait entails some production cost. Inaccordance to what Lankau suggested (Lankau 2008), a strongly allelopathic species whichplanted in an area for many times and dominate, it might initially outcompete other species,rising in relative abundance. As autoxins accumulated, this specie will decline, and otherspecies individuals will compete mostly with conspecifics, and selection would then favorlower levels of the allelopathic trait. While if levels of the allelopathic trait from differentspecies before and concentration levels were lower enough, then the autotoxic species couldrevived, and the cycle would start again (Lankau 2008). Therefore, different species in acommunity that invest lightly in chemical variation would be likely to affect other specispositively. Given the process of speices-specific autotoxicity, a monospecific stand willbuild-up a negative feedback in time, differently. In other words, a mixed species stand will5