乳油木幼苗对不同水分胁迫强度的生理响应

Physiological Response of Vitellaria paradora Seedlings to Different Water Stress Intensity

为了探明不同的水分胁迫强度下乳油木幼苗的生理响应机制,以及其生长发育过程中的需水关键期和适宜的浇水量,以乳油木幼苗为试验材料,设置两组不同的盆栽水分胁迫试验进行研究。结果表明,不同强度干旱胁迫试验中,叶片SOD酶活性变化幅度较大,土壤相对含水量从26%下降到15%时,酶活性显著降低了74.6%;POD、CAT酶活性无明显变化趋势。不同土壤水分胁迫试验中,叶片的SOD酶活性变化差异性显著,在土壤相对含水量达到40%时活性最大;POD、CAT酶活性变化不显著;叶片MDA含量在土壤相对含水量40%时最低。到胁迫后期,两组试验乳油木幼苗叶片的脯氨酸含量显著增加,说明脯氨酸积累对干旱胁迫反应较可溶性糖和可溶性蛋白更为强烈和敏感。研究表明,在土壤相对含水量40%左右时较适宜乳油木幼苗生长,土壤相对含水量26%左右是乳油木幼苗生长的需水关键期。

In order to find out the physiological response mechanism of Vitellaria paradora seedlings under different water stress intensity,as well as the critical period of water demand and suitable watering quantity in the process of growth and development,V.paradora seedlings were used as experimental materials,and two groups of different pot water stress experiments were set up.The results showed that in the different intensity drought stress experiments,with the extension of the test time and the deepening of the stress degree,the change range of leaf SOD enzyme activity was greater,and when the soil water content decreased from 26%to 15%,the enzyme activity decreased significantly by 74.6%,and the CAT enzyme activity had no obvious change trend.In different soil water stress experiments,the change of SOD enzyme activity of leaves was significant,and reached the maximum when the soil relative water content reached 40%;the change of POD and CAT enzyme activity was not significant.The MDA content of leaves was the lowest when the soil relative water content was 40%.The proline content in the leaves of V.paradora seedlings increased significantly in the late stage of stress,indicating that proline accumulation was more intense and sensitive to drought stress than soluble sugar and soluble protein.This study shows that when the soil relative water content is about 40%,it is more suitable for V.paradora seedling growth,and about 26%soil relative water content is the key period of water demand for V.paradora seedling growth.