黄河三角洲贝壳堤岛叶底珠叶片光合作用对CO2浓度及土壤水分的响应

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 黄河三角洲贝壳堤岛叶底珠叶片光合作用对CO2浓度及土壤水分的响应 DOI: 10.5846/stxb201305060935 作者: 作者单位: 山东农业大学,山东省黄河三角洲生态环境重点实验室,山东农业大学林学院、山东省土壤侵蚀与生态修复重点实验室,山东农业大学林学院、山东省土壤侵蚀与生态修复重点实验室,山东省邹平水务局,山东省黄河三角洲生态环境重点实验室 作者简介: 通讯作者: 中图分类号: Q945.1 基金项目: 国家自然科学基金（31100468）；山东省高校科研发展计划项目（J13LC03）；山东省优秀中青年科学家科研奖励基金（BS2013NY010）；山东省黄河三角洲生态环境重点实验室开放基金项目（2012KFJJ04） Photosynthetic responses to changes in CO2 concentration and soil moisture in leaves of Securinega suffruticosa from shell ridge islands in the Yellow River Delta, China Author: Affiliation: Shandong Agricultural University,Shandong Provincial Key Laboratory of Eco-Environmental Science for Yellow River Delta,Binzhou University,Shandong SProvincialS key SLaboratoryS of soil erosion and ecological restoration,Shandong SProvincialS key SLaboratoryS of soil erosion and ecological restoration,Zouping Water Conservancy Department,Zouping,Shandong Provincial Key Laboratory of Eco-Environmental Science for Yellow River Delta,Binzhou University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为阐明黄河三角洲贝壳砂生境叶底珠叶片光合作用对CO2浓度的响应规律，明确其光合生产力与土壤水分的定量关系，以2年生叶底珠（Securinega suffruticosa）苗木为材料，采用旱棚人工控水试验，利用光合测定系统测定分析了不同水分条件下叶底珠叶片光合作用的CO2响应特征。结果表明，叶底珠叶片净光合速率（Pn）和光合作用特征参数对土壤水分（SRWC）变化具有阈值效应。维持叶底珠叶片较高光合生产力的SRWC为50.3%-83.2%，CO2浓度为700-1100 μmol/mol，其中最适宜的SRWC为70.5%，最大值出现在CO2浓度为900 μmol/mol，而正常CO2浓度和倍增CO2浓度下维持叶底珠叶片较高光合生产力水平的SRWC范围分别为45.5%-90.0%和47.0%-92.6%。叶底珠叶片表观最大净光合速率（Pmax，c）和羧化效率（CE）随着SRWC的增加而呈抛物线变化。CO2补偿点（Г）呈现与Pmax，c和CE相反的变化规律，在SRWC为70.5%时，Г达到最低值（51.3 μmol/mol）。光呼吸速率（Rp）在SRWC为50.3%时达到最小值（2.62 μmol·m-2·s-1），随着SRWC的增加，Rp增加缓慢。说明黄河三角洲贝壳砂生境条件下，叶底珠叶片光合作用对CO2浓度和土壤水分具有宽泛的适应范围，对贝壳砂生境经常出现的干湿交替逆境表现出一定适应能力，在黄河三角洲贝壳堤岛可引种栽培。 Abstract:Atmospheric CO2 concentrations, soil moisture, and photosynthetically active radiation are the major factors limiting plant growth and photosynthetic productivity in large areas of the world. These factors affect agricultural and forest production and the distribution and composition of vegetation. Human activities have resulted in increased CO2 concentrations in the atmosphere, leading to changes in temperature, water cycling, and radiation. CO2 is required for photosynthesis, and the ongoing increases in atmospheric CO2 concentrations could eventually lead to higher temperatures and greater evaporative demands. Hence, droughts will be more frequent, intense, and erratic, and may affect regions that are not currently affected by drought. The effect of changes in CO2 concentrations and soil water content on plants is an important theme in studies on global change. To date, few studies have assessed the effects of continuous increases in CO2 concentration and soil moisture on photosynthesis. Securinega suffruticosa is one of the dominant drought-tolerant species growing on the shell islands in the Yellow River Delta region. To investigate the carbon and water cycles of the ecological system in this region, it is important to investigate the photosynthetic responses of S. suffruticosa to changes in CO2 concentrations and soil moisture conditions. This has important practical significance both in terms of food safety and for constructing, improving, and managing a functional ecological environment as the global climate changes.The study materials were 2-year-old plants of S. suffruticosa, originally from the shell islands in the Yellow River Delta. These plants were obtained from a nursery. The plants were subjected to seven different levels of water supply using an artificial water control system in a covered shed, and to a series of CO2 concentrations controlled using a LI-COR 6400 portable photosynthesis system. The objective of this study was to investigate photosynthetic responses to CO2 concentrations and determine whether photosynthetic productivity was quantitatively related to soil moisture content. The photosynthetic rate (Pn) and characteristic parameters of photosynthesis showed threshold-value responses to variations in soil relative water content (SRWC). S. suffruticosa plants were able to maintain higher photosynthetic productivity in the range of 50.3% to 83.2% RWC; in this range, the range of suitable CO2 concentrations was 700 to 1100 μmol/mol, and Pn increased with increasing CO2 concentrations. The most suitable SRWC was 70.5%, and Pn peaked at the CO2 concentration of 900 μmol/mol. The characteristic parameters of photosynthesis showed different responses to changes in SRWC. Under normal and double CO2 concentrations, the ranges of SRWC in which S. suffruticosa maintained higher photosynthetic productivity were 45.5%-90.0% and 47.0%-92.6%, respectively, indicating that S. suffruticosa was highly adaptable to changes in soil moisture content. The apparent maximum photosynthesis rate (Pmax,c) and carboxylation efficiency (CE) increased with increasing SRWC, peaking at 70.5% SRWC and then decreasing slowly at higher SRWC. The CO2compensation point showed the opposite trend to that of Pmax,c and CE, and reached a minimum value (approx. 51.3 μmol/mol) at 70.5% SRWC. The photorespiration rate increased slowly with increasing SRWC and peaked at approximately 2.6175 μmol·m-2·s-1 at 50.3% SRWC.We concluded that photosynthesis in leaves of S. suffruticosa is widely adaptable to changes in CO2 concentrations and soil moisture, and that this species has the typical physiological characteristics of a water-tolerant and drought-tolerant plant. Thus, S. suffruticosa has the potential for cultivation on the shell ridge islands of the Yellow River Delta, China. 参考文献 相似文献 引证文献