干旱胁迫对木地肤幼苗生理生化特性的影响

Effects of Drought Stress on Physiological and Biochemical Properties of Kochia prostrata(L.)Schrad.Seedlings

对水分胁迫下木地肤幼苗的超氧化物歧化酶活性、叶绿素、类胡萝卜素、可溶性糖、游离脯氨酸、丙二醛等生理生化指标进行了研究。结果表明:经水分胁迫后,木地肤幼苗叶内叶绿素、类胡萝卜素含量下降;超氧化物歧化酶活性先上升、后下降,胁迫14 d后达到最高峰;水分胁迫造成木地肤幼苗的膜脂过氧化,可溶性糖和丙二醛含量明显升高,超氧化物歧化酶活性的增强可以降低丙二醛的含量;脯氨酸含量则随着胁迫时间的延长迅速升高。研究表明,可以用超氧化物歧化酶活性、游离脯氨酸和丙二醛含量的高低作为衡量木地肤抗旱性的指标。

In this paper, some physiological and biochemical properties of Kochia prostrata seedlings under water stress, such as the activity of superoxide dismutase （SOD） and the concentrations of chlorophyll, carotenoids, soluble sugars （SS）, free proline （Pro） and malondialdehyde （MDA）, are lucubrated. The experiment is carried out at Xinjiang Xeric Forage Seed Breeding Farm （44^.14＇N, 86^o37’E, 504 m a. s. l. ）, Ministry of Agriculture. The farm is located in Hutubi County in the central piedmont plain on the northern slope of the Tianshan Mountains, where the annual temperature and the monthly temperatures in July and January are 6.7℃, 25.6℃ and - 15.1 ℃ respectively, the accumulative temperature ≥10℃ is 3 881℃, the annual precipitation and evaporation are 167 mm and 2 361 mm respectively, and the frost-free period is 170 days. The results reveal that water stress makes the concentrations of chlorophyll and carotenoids decrease; the SOD activity is increased at the beginning of water stress, and then decreased. After 14-day water stress, the SOD activity is increased to the maximum. The concen- trations of MDA and SS are significantly increased with increasing water stress. Moreover, the increase of SOD can decrease the MDA concentration. The concentration of Pro is rapidly increased with increasing the time of water stress. There is a negative correlation between the SOD activity and the MDA concentration. According to the study results, it is considered the SOD activity, MDA and Pro concentrations can be regarded as the indexes to judge the drought resistance of Kochia prostrata seedlings.