干旱胁迫对胡杨和灰胡杨幼苗渗透调节物质及抗氧化酶活性的影响  

Effects of drought stress on osmotic adjustment substances and antioxidant enzymes activity of Populus euphratica and Populus pruinosa seedlings

作　　者：王海珍[1,2] 徐雅丽[1] 张翠丽[1] 韩路[1,2] 

机构地区：[1]塔里木大学植物科学学院,阿拉尔843300 [2]塔里木盆地生物资源保护利用兵团重点实验室,阿拉尔843300

出　　处：《干旱区资源与环境》2015年第12期125-130,共6页Journal of Arid Land Resources and Environment

基　　金：国家自然科学基金项目(31260058);中国科学院"西部之光"人才培养项目(RCPY201209)资助

摘　　要：以塔里木荒漠优势树种胡杨(Populus euphratica Oliv.)和灰胡杨(Populus pruinosa Schrenk)幼苗为试验材料,利用盆栽控水方法模拟不同程度干旱胁迫对两苗木主要渗透调节物质及抗氧化酶活性的影响。结果表明:干旱胁迫下两幼苗通过积累渗透调节物质、提高抗氧化保护酶活性来抵御干旱胁迫。两树种抗旱方式不同,胡杨幼苗以大量积累可溶性糖(SS)、维持可溶性蛋白质(SP)基本稳定为特征,而灰胡杨幼苗则以积累大量游离脯氨酸(Pro)来提高其抗旱性。胡杨幼苗的超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性均高于灰胡杨幼苗,随干旱胁迫加剧SOD活性降幅小,而POD活性大幅增加,是灰胡杨幼苗的60.9倍,严重干旱胁迫条件下其POD活性虽有所下降,但仍能较长时间地保持较高的活性。胡杨幼苗高活性的POD与SOD协同作用,清除活性氧自由基能力远大于灰胡杨幼苗,表现在干旱胁迫下其丙二醛(MDA)含量显著低于灰胡杨幼苗,灰胡杨幼苗MDA含量增幅与干旱胁迫程度及干旱持续时间有关。总体看胡杨幼苗对土壤干旱的适应和忍耐性要高于灰胡杨幼苗。The objective of the experiment was to investigate the effect of simulated soil moisture gradient on osmotic adjustment substances and antioxidant enzymes activity of Populus euphratica and Populus pruinosa seedlings and to illuminate the drought- resistant mechanism of two dominant tree species with pot- culture experiment in Tarim desert region. The results showed that two dominant tree species accumulated osmotic adjustment substances and improved antioxidant enzymes activity to resist drought stress. P. euphratica accumulates large amount of soluble sugar and maintains relative stability of soluble protein,and P. pruinosa accumulates lots of free proline to strengthen drought- resistant ability. P. euphratica has higher activity of superoxide dismutase（ SOD）and peroxides（ POD） than that of P. pruinosa,its SOD activity decreases in a relative small extent and POD activity increases significantly with intense drought stress,and its POD content is 60. 9 times than P. pruinosa.Otherwise,POD activity of P. euphratica decreases obviously under severe drought stress and it always maintains a relatively high activity in growth season. P. euphratica has strong ability to scavenge reactive oxygen radicals by cooperating with high activity of SOD and POD than P. pruinosa,as a result,its malondialdehyde（ MDA）content is significantly lower than P. pruinosa under mild and medium drought stress. Increase level of MDA content of P. pruinosa is related to the degree of drought stress and drought duration. Overall P. euphratica seedlings have higher drought- resistant ability and ecological adaptability to water stress than that of P. pruinosa.These findings indicate that P. euphratica is the preferred tree species than P. pruinosa in establishing shelter forest on farmlands in Tarim basin.

关 键 词：胡杨 灰胡杨 干旱胁迫 渗透调节物质 抗氧化酶 

分 类 号：Q945[生物学—植物学] S758[农业科学—森林经理学]