降雨量增减对黄河三角洲滨海湿地土壤呼吸和光合作用的影响

发布时间：2018-01-04 15:44

本文关键词：降雨量增减对黄河三角洲滨海湿地土壤呼吸和光合作用的影响　出处：《聊城大学》2017年硕士论文　论文类型：学位论文

【摘要】：滨海湿地地下水位浅,淡咸水垂直交互作用明显,全球气候变化背景下降水变异改变其土壤表层水盐状况,从而影响植物光合作用与土壤呼吸。为探究降雨量变化对黄河三角洲滨海湿地土壤呼吸和光合特性的影响,采用固定式遮雨顶棚和雨水输送管道相结合的方法设置增减雨处理小区,于2015年生长季测定土壤呼吸季节动态和光合作用光响应曲线,同时连续测定土壤温度、土壤含水量、土壤盐分含量等土壤环境因子。得到如下结果:在生长季,增雨处理下土壤含水量提高了10.2%,土壤盐分含量降低了24.3%,植物群落多样性和丰富度指数均显著提高;减雨处理下土壤含水量降低24.6%,土壤盐分含提高20.8%,降低植物群落多样性和丰富度指数,显著降低了38.9%的土壤呼吸;降雨量增减均未对生长季尺度植物光合作用产生显著影响。根据土壤含水量波动情况可将生长季分为3个阶段,即干旱期、湿润期、淹水期。不同土壤水分阶段,土壤呼吸和芦苇光合特性对降雨量增减的响应不同。(1)在干旱期,水分亏缺和盐胁迫是抑制滨海湿地地上植物生长和地下生物化学过程的主要逆境。增雨处理下土壤含水量提高了21.5%,土壤盐分含量降低了9.5%,导致土壤呼吸速率显著提高了31.8%,芦苇叶片气孔导度和光合能力显著增强;减雨处理下土壤含水量下降29%,土壤盐分含量提高21.9%,导致土壤呼吸速率降低41.1%,芦苇叶片气孔阻塞,光合能力降低。(2)在湿润期,增雨和减雨处理使得土壤水分含量显著增加和降低了9.9%和14.2%,导致土壤呼吸速率及其温度敏感性指数(Q10)均出现下降,但是增减雨处理未对芦苇各光合参数和净光合速率产生显著影响。(3)在淹水期,增减雨处理未对土壤呼吸产生显著影响,但芦苇对淹水胁迫较为敏感,增减雨分别加重和降低了淹水对芦苇植株的伤害,光合速率由高到低为减雨对照增雨。
[Abstract]:The groundwater level of coastal wetland is shallow, the vertical interaction of brackish water is obvious, and the variation of precipitation under the background of global climate change changes the soil surface water and salt status. In order to investigate the effect of rainfall on soil respiration and photosynthesis in coastal wetland of Yellow River Delta. The soil respiration season dynamics and photosynthesis light response curves were measured in 2015 during the growing season by using the method of combining fixed rain shelter and Rain Water transportation pipeline to set up the increasing and decreasing rainfall treatment area. At the same time, soil temperature, soil water content, soil salt content and other soil environmental factors were determined continuously. The results are as follows: in the growing season, the soil water content increased by 10.2%. The soil salt content decreased by 24.3and the plant community diversity and richness index increased significantly. Soil water content decreased by 24.6g / L, soil salt content increased by 20.8m, plant community diversity and richness index decreased, soil respiration decreased significantly by 38.9% under rain reduction treatment. According to the fluctuation of soil water content, the growing season can be divided into three stages, that is, drought period and wet period. The response of soil respiration and Reed photosynthesis to rainfall increase and decrease was different in different soil moisture stage. Water deficit and salt stress were the main stresses to inhibit the growth of aboveground plants and underground biochemical processes in coastal wetlands. The soil water content increased by 21.5g and the soil salt content decreased by 9.5%. As a result, the soil respiration rate increased significantly by 31.8%, and the stomatal conductance and photosynthetic ability of Reed leaves increased significantly. Soil moisture content decreased 29%, soil salt content increased 21.9%, soil respiration rate decreased 41.1%, stomatal obstruction and photosynthetic ability decreased in Reed leaves during wet period. The soil moisture content increased significantly and decreased by 9.9% and 14.2, which resulted in the decrease of soil respiration rate and temperature sensitivity index (Q10). However, no significant effect on the photosynthetic parameters and net photosynthetic rate of Reed was found in the treatment of increasing and decreasing rain, and no significant effect on soil respiration was found in the treatment of increasing or decreasing rain during the flooding period, but the Reed was more sensitive to flooding stress. The increase and decrease of rain increased and decreased the damage to Reed plants by flooding, and the photosynthetic rate increased from high to low.
【学位授予单位】：聊城大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q948.113

【相似文献】