Hochwender C G, Marquis R J, Stowe K A
Department of Biology, University of Missouri-St. Louis, 8001 Natural Bridge Road, St. Louis, MO 63121-4499, USA, , , , , , US.
Oecologia. 2000 Feb;122(3):361-370. doi: 10.1007/s004420050042.
To investigate the potential for and constraints on the evolution of compensatory ability, we performed a greenhouse experiment using Asclepias syriaca in which foliar damage and soil nutrient concentration were manipulated. Under low nutrient conditions, significant genetic variation was detected for allocation patterns and for compensatory ability. Furthermore, resource allocation to storage was positively, genetically correlated both with compensatory ability and biomass when damaged, the last two being positively, genetically correlated with each other. Thus, in the low nutrient environment, compensatory ability via resource allocation to storage provided greater biomass when damaged. A negative genetic correlation between compensatory ability and plant biomass when undamaged suggests that this mechanism entailed an allocation cost, which would constrain the evolution of greater compensatory ability when nutrients are limited. Under high nutrient conditions, neither compensatory ability nor allocation patterns predicted biomass when damaged, even though genetic variation in compensatory ability existed. Instead, plant biomass when undamaged predicted biomass when damaged. The differences in outcomes between the two nutrient treatments highlight the importance of considering the possible range of environmental conditions that a genotype may experience. Furthermore, traits that conferred compensatory ability did not necessarily contribute to biomass when damaged, demonstrating that it is critical to examine both compensatory ability and biomass when damaged to determine whether selection by herbivores can favor the evolution of increased compensation.
为了研究补偿能力进化的潜力和限制因素，我们使用马利筋进行了一项温室实验，在实验中对叶片损伤和土壤养分浓度进行了控制。在低养分条件下，检测到了分配模式和补偿能力方面显著的遗传变异。此外，分配到储存的资源与补偿能力以及受损时的生物量呈正遗传相关，后两者之间也呈正遗传相关。因此，在低养分环境中，通过将资源分配到储存来实现的补偿能力在受损时能提供更多生物量。补偿能力与未受损时的植物生物量之间存在负遗传相关，这表明这种机制存在分配成本，在养分有限时会限制更强补偿能力的进化。在高养分条件下，即使存在补偿能力的遗传变异，补偿能力和分配模式都无法预测受损时的生物量。相反，未受损时的植物生物量能预测受损时的生物量。两种养分处理结果的差异凸显了考虑基因型可能经历的环境条件范围的重要性。此外，赋予补偿能力的性状在受损时不一定对生物量有贡献，这表明在确定食草动物的选择是否有利于增强补偿能力的进化时，同时考察补偿能力和受损时的生物量至关重要。
