South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.
J Chem Ecol. 2011 Jul;37(7):785-93. doi: 10.1007/s10886-011-9970-z. Epub 2011 Jun 18.
Plants release secondary metabolites into the soil that change the chemical environment around them. Exogenous abscisic acid (ABA) is an important allelochemical whose role in successional trajectories has not been examined. We hypothesized that ABA can accumulate in the soil through successional processes and have an influence on forest dynamics. To this end, we investigated the distribution of ABA in forest communities from early to late successional stages and the response of dominant species to the gradient of ABA concentrations in three types of forests from northern to southern China. Concentrations of ABA in the soils of three forest types increased from early to late successional stages. Pioneer species' litters had the lowest ABA content, and their seed germination and seedling early growth were the most sensitive to the inhibitory effect of ABA. Mid- and late-successional species had a much higher ABA content in fallen leaves than pioneer species, and their seed germination and seedling early growth were inhibited by higher concentrations of ABA than pioneers. Late-successional species showed little response to the highest ABA concentration, possibly due to their large seed size. The results suggest that ABA accumulates in the soil as community succession proceeds. Sensitivity to ABA in the early stages, associated with other characteristics, may result in pioneer species losing their advantage in competition with late-successional species in an increasingly high ABA concentration environment, and being replaced by ABA-tolerant, late-successional species.
植物会向土壤中释放次生代谢物，从而改变其周围的化学环境。外源脱落酸（ABA）是一种重要的化感物质，但其在演替轨迹中的作用尚未被研究过。我们假设 ABA 可以通过演替过程在土壤中积累，并对森林动态产生影响。为此，我们研究了从早期演替到晚期演替阶段的森林群落中 ABA 的分布，以及在中国北方到南方三种不同森林类型中 ABA 浓度梯度对优势物种的响应。三种森林类型土壤中 ABA 的浓度从早期演替到晚期演替阶段逐渐增加。先锋物种凋落物中的 ABA 含量最低，其种子萌发和幼苗早期生长对 ABA 的抑制作用最敏感。与先锋物种相比，中晚演替物种的落叶中 ABA 含量更高，其种子萌发和幼苗早期生长受到更高浓度 ABA 的抑制。晚演替物种对最高 ABA 浓度的反应较小，可能是由于其种子较大。研究结果表明，随着群落演替的进行，ABA 在土壤中积累。在早期阶段对 ABA 的敏感性，以及其他特征，可能导致先锋物种在越来越高的 ABA 浓度环境中丧失与晚演替物种竞争的优势，并被 ABA 耐受的晚演替物种所取代。
