民勤绿洲梭梭同化枝光合生理特性与形态  

Photosynthetic,physiological,and morphological characteristics of Haloxylon ammodendron assimilation twigs in Minqin Oasis

作　　者：张华[1,2] 吴睿[1] 康雅茸 

机构地区：[1]西北师范大学地理与环境科学学院,甘肃兰州730070 [2]兰州大学生命科学学院,甘肃兰州730000

出　　处：《草业科学》2018年第2期371-379,共9页Pratacultural Science

基　　金：国家自然科学基金(41461011)

摘　　要：梭梭(Haloxylon ammodendron)是干旱区植被组成中的植被优势种,对区域生态系统稳定有着重要的作用。为进一步揭示生长季内不同时期梭梭同化枝光合生理特性和形态性状及其对环境因子的适应,本研究比较分析了民勤绿洲梭梭同化枝在5月下旬和7月下旬的光合生理特性及形态。结果表明,5月下旬和7月下旬梭梭同化枝净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)的日变化均呈现双峰曲线。5月下旬中午前后Pn降低主要是气孔限制因素,7月下旬中午前后Pn降低主要是非气孔限制因素。7月下旬的同化枝面积(LA)、鲜重(FW)、干重(DW)、含水量(LWC)、干物质含量(LDMC)和比叶面积(SLA)较5月下旬分别增长了79%、94%、99%、33%、14%和3%。LA是梭梭同化枝最具代表性的形态性状。影响5月下旬梭梭同化枝的环境因子主要是光合有效辐射(PAR)、空气相对湿度(RH)和土壤含水量(SWC),影响7月下旬的主要是大气温度(Ta)和SWC。Haloxylon ammodendron is a dominant species in arid zones and plays an important role in regional ecosystem stability. In order to more fully understand the photosynthetic,physiological,and morphological characteristics of H.ammodendron and to determine how they adapt to environmental factors,we employed comparative analytical methods to study these traits at the end of May and the end of July in Minqin Oasis. Our results showed that the change trends for assimilation twigs were bimodal on a daily scale for net photosynthetic rate(Pn),transpiration rate(Tr),and stomatal conductance(Gs) in May and July. The Pnreduction was mainly due to stomatal limitation factors in May; the Pnreduction was caused by non-stomatal limitation factors in July. Morphological characteristics,including area(LA),fresh weight(FW),dry weight(DW),water content(LWC),dry matter content(LDMC),and specific leaf area(SLA)increased by 79%,94%,99%,33%,14%,and 3%,respectively,in July more than in May. Area was the most representative morphological character of the assimilation twigs. The environmental impact factors of H. ammodendron were mainly photosynthetically active(PAR),air relative humidity(RH),and soil water content(SWC) in May. Other factors of importance were atmospheric temperature(Ta) and SWC in July.

关 键 词：光合作用 同化枝 生理性状 形态性状 梭梭 民勤 

分 类 号：S543.9[农业科学—作物学] Q945.11[生物学—植物学]