机构地区:[1]西北师范大学地理与环境科学学院,甘肃省湿地资源保护与产业发展工程研究中心,兰州730070
出 处:《生态学报》2018年第16期5819-5827,共9页Acta Ecologica Sinica
基 金:国家自然科学基金项目(41461013,91125014,41361010);甘肃省生态学重点学科基金项目
摘 要:植物蒸腾速率与叶性状关系的环境响应,对探索植物碳水代谢关系和叶性状构建模式之间耦合的生理生态学机制具有重要的意义。选择甘肃省秦王川国家湿地公园的盐沼湿地为实验地,按研究区域滨藜(Atriplex patens)植株密度设置Ⅰ(16—21株/m^2)、Ⅱ(9—15株/m^2)、Ⅲ(<9株/m^2)3个梯度,采用标准化主轴估计(standardized major axis estimation,SMA)方法,以叶脉密度和中脉直径分别表示叶脉性状,研究了种群密度影响下滨藜蒸腾速率与叶脉性状的关系。结果表明:随种群密度减小,滨藜的中脉直径、株高、盖度、光合有效辐射(PAR)、叶面积(LA)均逐渐降低,而叶脉密度、叶干重、蒸腾速率(T_r)和净光合速率(P_n)逐渐增加。在高密度(Ⅰ)和低密度(Ⅲ)中,滨藜的蒸腾速率和叶脉密度之间存在极显著正相关关系(P<0.01),与中脉直径之间存在显著的负相关关系(P<0.05);在中密度(Ⅱ)中,滨藜的蒸腾速率与叶脉密度呈显著正相关关系(P<0.05),与中脉直径不存在相关关系(P>0.05)。在小密度样地,蒸腾速率(T_r)较小,滨藜采取减小叶脉密度、增大中脉直径的策略,即在阴生环境中滨藜叶片需要大的中脉直径来支撑,同时较小的叶脉密度亦可满足其蒸腾需求,体现了密度制约下湿地植物的生物量分配格局和资源利用对策。The environmental response of plant relationships between transpiration rate and leaf traits is of vital significance to explore the ecophysiological mechanism of the coupling of plant carbohydrate metabolism and building modes for leaf traits. The objective of this study was to examine the relationship between atriplex (Atriplex patens) transpiration rate and vein density and midrib diameter under the influence of different population densities. The study site was located in the national wetland park conservation areas in Qinwangchuan, Gansu Province, China (36°27'59.6″ N,103°39'5.6″ E). The study area was on a platform at the center of the wetland, gently transiting through the wetland community, in which atriplex was the single dominant species. The sample area was divided into 3 levels based on plant density, high (I, 16-21 plant/m^2), medium (Ⅱ, 9-15 plant/m^2) and low (Ⅲ, 〈 9 plant/m^2), In order from bottom to top, six (2 m×2 m) atriplex samples were selected per plot, numbering 24 samples (4×6) in all. Then, community traits (height and coverage) and soil moisture were determined and 6 individuals of Atriplex patens were taken to the laboratory to measure the leaf thickness, leaf area, vein density, and midrib diameter. In addition, the leaf net photosynthetic rate (Pn), transpiration rate (Tr) and other parameters of the atriplex were measured in each plot. Quadrat survey methods were used to determine the relationship between transpiration rate and leaf traits of the atriplex. The results show that when the soil population density was decreased, the wetland vegetation community height and coverage presented increasing-decreasing changing trends; vein density (VD) and leaf transpiration rate (Tr) presented increasing trends, and the midrib diameter (MD) displayed a decreasing trend. There was a highly significant positive correlation (P 〈 0.01) between Tr and VD, and there was a significant negative correlation (P 〈 0.05) b
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