伊桐(Itoa orientalis)幼苗对土壤干旱与盐胁迫的生长及生理响应

Growth and Physiological Responses to Soil Drought and Salt Stress in Itoa orientalis Seedlings

以伊桐2年生实生苗为研究材料,对其进行良好水分处理(100%田间持水量)、干旱处理(50%田间持水量)和0.1 mol/L盐溶液处理,比较伊桐幼苗的形态生长、生物量分配、光合色素含量、抗氧化酶活性及可溶性渗透调节物质等生长特性和生理生化特性对干旱胁迫与盐胁迫的响应差异。结果表明:①土壤干旱胁迫与盐胁迫在一定程度上降低了植株叶片相对含水量,影响了伊桐幼苗的形态生长,减少了其生物量积累,增加了胡萝卜素含量,从而减小了光合叶绿素含量,增加了植株抗氧化系统的活性及渗透调节物质的含量。②伊桐幼苗形态生长及生理生化特性对土壤干旱胁迫和盐胁迫的响应存在一定的差异:伊桐幼苗受盐胁迫的不良影响要大于干旱胁迫,说明伊桐具有一定的抗旱性,但耐盐性却较低。

In this study,the two-years old seedlings of Itoa orientalis were used as experiment materials,the growth,physiological and biochemical traits of seedlings including leaf morphology,plant growth,biomass allocation,photosynthetic pigments,antioxidative enzyme activities and osmotic adjustment substances were investigated under three treatments（well-watered,100 %FC;soil drought stress,50 %FC;salt stress by 0.1 % NaCl solution）.The majorfindings were as follows：（ⅰ）The growth and morphology of Itoa orientalis were affected more or less by soil drought and salt,the leaf relative water content and biomass allocation decreased under this two stresses.For the physiological and biochemical traits,the carotenoid content was improved while the chlorophyll content reduced;moreover,the antioxidative enzyme activities and osmotic adjustment substances increased under drought and salt stress.（ⅱ） There was different between the responses of Itoa orientalis seedlings to soil drought and to salt： the negative effect on growth and physiological traits of salt was more evident than that of drought,indicating Itoa orientalis was more tolerant to drought but more sensitive to salt.