干旱胁迫对夏蜡梅光合特性的影响  

Photosynthetic Characteristics of Sinocalycanthus chinensis Leaves under Drought Stress

作　　者：柯世省[1] 

机构地区：[1]台州学院生命科学学院,浙江临海317000

出　　处：《西北植物学报》2007年第6期1209-1215,共7页Acta Botanica Boreali-Occidentalia Sinica

基　　金：浙江省自然科学基金资助项目(Y504256);浙江省教育厅科研计划资助项目(20030769)

摘　　要：以2年生夏蜡梅(Sinocalycanthus chinensis)苗木为材料,通过盆栽试验,研究土壤干旱胁迫对夏蜡梅叶片光合特性的影响,结果显示:随着干旱胁迫程度的加重,夏蜡梅叶片净光合速率、蒸腾速率、气孔导度显著降低;胞间CO2浓度在轻度和中度胁迫下显著低于对照,但在重度胁迫下显著高于对照;水分利用效率在胁迫下提高,且以中度胁迫为最大.温度升高使叶片净光合速率和水分利用效率降低、蒸腾速率升高,加重了干旱对光合作用的不利影响.对照及轻度和中度干旱胁迫处理的净光合速率、气孔导度和水分利用效率日变化曲线均为双峰型,但重度胁迫下净光合速率和气孔导度日变化转变为峰值很小的单峰型;各处理的蒸腾速率日变化曲线为单峰型并以午间最高.表明夏蜡梅光合作用对干旱胁迫有一定的适应能力,但重度胁迫对其造成严重影响.The effects of soil drought stress on photosynthetic characteristics of Sinocalycanthus chinensis leaves were studied by the test of potted 2-years-old Sinocalycanthus chinensis seedlings. The results showed as follows： with the increases in drought stress, net photosynthetic rate （Pn）, transpiration rate （Tr） and stomatal conductance （Cs） markedly decreased,while water use efficiency （WUE） increased and the maximal WUE occurred under moderate stress. Compared with control （CK）, remarkable decreases of intercellular CO2 concentration （Ci） under mild and moderate stress and remarkable increase under severe stress were observed. The test of response of photosynthesis to temperature exhibited an obvious decline of Pn and increase of Tr under higher temperature, so WUE decreased. Higher temperature aggravated the stress effects of drought on photosynthesis. The diurnal variation curves of Pn,Cs and WUE were doublepeak types under different water treatments,but the curves of Pn and Cs turned to single-peak types with low peak values under severe stress. The curves of Tr were single-peak types showing the maximums at noon. The present conclusion is that the photosynthesis of S. chinensis exhibits a certain adaptability to drought stresses except severe stress.

关 键 词：干旱胁迫 光合特性 温度响应 日变化 夏蜡梅 

分 类 号：Q945.78[生物学—植物学]