微生境对黄梅秤锤树野生种群叶片功能性状的影响

植物功能性状可以反映植物应对环境变化的适应策略。本文以黄梅秤锤树(Sinojackia huangmeiensis)当前唯一野生种群为对象, 比较了3种微生境(湖边、种群中心、耕地边)中该物种的叶片功能性状均值、种内变异和叶片生态化学计量特征的差异, 分析了黄梅秤锤树对湖岸带微生境变化的响应及其适应策略。结果表明: (1) 3种微生境中土壤C、N、P含量没有显著性差异(P > 0.05), 但土壤C∶N和C∶P具有显著性差异(P < 0.05), 土壤类型和养分条件有所不同。(2)黄梅秤锤树叶片功能性状的比较用单因素方差分析和贝叶斯方差分析得出的结果一致, 均为叶长、叶面积和比叶面积在中心区域显著高于湖边(P < 0.05), 而耕地边与湖边和中心区域均没有显著差异(P > 0.05); 叶N含量在湖边显著高于中心区域和耕地边(P < 0.05), 而中心区域和耕地边间没有显著差异(P > 0.05); 叶宽、叶长/叶宽、叶干物质含量、叶C和叶P含量在3种微生境间都没有显著性差异(P > 0.05)。(3)黄梅秤锤树叶片的N∶P在湖边显著高于中心区域和耕地边(P < 0.05), C∶N在湖边显著小于中心区域和耕地边(P < 0.05), N∶P和C∶N在中心区域和耕地边没有显著性差异(P > 0.05), C∶P在3种微生境间都没有显著性差异(P > 0.05)。(4)黄梅秤锤树叶片功能性状的总体变异程度在0.02-0.28之间, 其中叶片C和N含量在湖边和中心区域的种内变异程度显著较低, 表明3种生境中湖边和中心区域黄梅秤锤树种群的稳定性相对较差。(5)湖边黄梅秤锤树主要通过增加叶N含量促进生长; 中心区域黄梅秤锤树主要通过增加叶面积和比叶面积以及提高叶N的利用效率来提高光捕获能力促进生长; 耕地边黄梅秤锤树的叶N含量和叶面积、比叶面积都处于中等水平, 通过性状之间的共同作用使植株生长达到最佳水平。以上结果表明, 由于微地形、水位波动和土壤环境条件的差异, 黄梅秤锤树对3种生境中的适应策略有所不同, 并且不是通过单一性状调整来适应环境的变化, 而是通过多种性状之间的权衡达到更好的适应效果。

Impacts of microhabitats on leaf functional traits of the wild population of Sinojackia huangmeiensis

Plant functional traits and stoichiometry characteristics can reflect differences in plant strategies to microenvironmental changes. In this study, we used a one-way ANOVA and Bayesian ANOVA to compare leaf functional traits, intraspecific variation, and leaf stoichiometry of Sinojackia huangmeiensis at three microhabitats (lakeside, population center, and cropland side) next to Longgan Lake, central China. Our results showed that: (1) There were no significant differences in soil C, N and P concentrations among the three microhabitats (P > 0.05), but soil C : N and C : P were significantly different (P < 0.05). (2) The results of one-way ANOVA and Bayesian ANOVA were similar when we compared mean values of leaf functional traits of S. huangmeiensis among the three microhabitats. Leaf length, leaf area, and specific leaf area were all significantly higher at population center than those at lakeside (P < 0.05), while the three leaf traits at cropland side were not different with those at lakeside or population center (P > 0.05); The leaf N content at lakeside was significantly higher than that at population center and cropland side (P < 0.05), but it was not different between population center and cropland side (P > 0.05); Leaf width, ratio of leaf length to leaf width, leaf dry matter content, leaf C content, and leaf P content were not significantly different among the three microhabitats (P > 0.05). (3) Leaf N : P of S. huangmeiensis at lakeside was significantly higher than that at population center and cropland side (P < 0.05). Leaf C : N at lakeside was significantly smaller than that at population center and cropland side (P < 0.05). Both leaf N : P and C : N were not different between population center and cropland side (P > 0.05). Leaf C : P was not different among the three microhabitats (P > 0.05). (4) The overall variation of leaf functional traits of S. huangmeiensis was between 0.02 and 0.28. Bayesian ANOVA showed that both leaf C and N contents had low degrees of intraspecific variation in lakeside and population center. (5) Sinojackia huangmeiensis’ growth was promoted by different factors at the varying microhabitats. Our results indicate that S. huangmeiensis strategies at three microhabitats were different and not single-trait dependent, but trade-off dependent to achieve a better adaptive effect.