羊草和紫花苜蓿生长特征及光合特性对不同土壤水分的响应  

Effects of soil moisture content on morphological and photosynthetic characteristics of Leymus chinensis and Medicago sativa

作　　者：于晓娜[1] 赵杰[1] 祁瑜[1] 黄永梅[1] 龚吉蕊[1] 

机构地区：[1]北京师范大学资源学院,北京100875

出　　处：《生态学报》2014年第21期6067-6075,共9页Acta Ecologica Sinica

基　　金：国家自然科学基金资助项目(40871031;41025001);长江学者和创新团队发展计划(IRT1108);中央高校基本科研业务费专项

摘　　要：采用人工控制实验,对12%(T1)、16%(T2)和20%(T3)3种土壤水分条件下羊草和紫花苜蓿的净光合速率Pn、实际光化学量子效率ФPSⅡ、光化学淬灭q P、非光化学淬灭q N、水分利用效率WUE、株高、分枝分蘖数、生物量等参数进行测定。结果表明,在实验范围内,(1)ФPSⅡ和q P共同影响净光合速率,羊草和紫花苜蓿净光合速率对土壤水分的响应不同,紫花苜蓿的土壤水分生态幅要比羊草窄,羊草生长的最适土壤含水量为20%,随着土壤含水量的降低,净光合速率呈单调递减趋势;紫花苜蓿的最适土壤含水量为16%,其净光合速率与土壤含水量之间呈非线性关系,存在明显阈值。(2)适宜土壤含水量有助于羊草和紫花苜蓿株高和分枝分蘖的生长。(3)在土壤水分低于适宜土壤含水量范围时,羊草和紫花苜蓿有相似的响应机制,都通过增加根系生物量来适应环境胁迫。Leymus chinensis and Medicago sativa are the two most significant perennial artificial grasses of the farmingpastoral ecotone of north China and are crucial for the development of animal husbandry in this area.In this region,water is an important ecological factor that limits plant ecophysiology and the growth of L.chinensis and M.sativa.To maximize the productivity of artificial grassland in this area,it is necessary to explore the mechanisms of the morphological and photosynthetic response characteristics of L.chinensis and M.sativa to water stress.Response characteristics,including the fluorescence characteristics,water use efficiency,biomass and biomass allocation to drought,are studied in this paper.This was done in order to propose the optimum soil moisture content for the growth of,and high economic benefits from,L.chinensis and M.sativa in the chestnut soil of the farming-pastoral ecotone of north China.Data on the morphological and photosynthetic characteristics of L.chinensis and M.sativa were collected from a controlled field experiment in the Taipusi Banner in Inner Mongolia.A water control experiment was applied from the 9thweek to the 13 thweek of the field experiment to evaluate leaf net photosynthetic rate（ Pn）,actual photochemical efficiency of photosystem Ⅱ complex in the light（ ФPSⅡ）,photochemical quenching（ q P）,non-photochemical quenching（ q N）,water use efficiency（ WUE）,plant height,branch number and tiller number per plant,biomass and biomass allocation in modules of L.chinensis and M.sativa.The experiment consisted of three soil moisture gradients of 12%,16% and 20%.The results indicated that,within the soil moisture range of the experiment：（ 1） the responses of Pn to soil moisture content of L.chinensis and M.sativa were different from each other,and the highest Pn depended on the highest ФPSⅡand q P.The most suitable soil moisture content for the growth of L.chinensis was 20% and with a decrease in soil moisture content,the Pn of L.chinensis also decreas

关 键 词：净光合速率 叶绿素荧光 生物量 土壤含水量 

分 类 号：S541.9[农业科学—作物学] S543.9