荒漠植物红砂根系对干旱胁迫的生理响应

Physiological responses of seedling roots of the desert plant Reaumuria soongoricato drought stress

以抗旱性不同的红砂2个种源2年生苗木为试材,通过盆栽实验,测定干旱胁迫后红砂苗木根系的活力、膜透性(RPP)、脯氨酸(Pro)、可溶性糖(SS)、可溶性蛋白(SP)、丙二醛(MDA)含量和抗氧化物酶系(SOD、POD、CAT)的活性变化,并通过灰色关联度法分析了各指标与红砂根系抗旱性的关系。结果表明,水分胁迫导致红砂根系活力下降,膜透性RPP和膜质过氧化产物MDA含量增加,渗透调节物质Pro含量、SS含量和SP含量明显增加,抗衰老酶SOD、POD和CAT活性显著升高,且抗性强的种源比抗性弱的种源对干旱胁迫的生理生化反应更明显。红砂根系的RPP、Pro和根系活力的关联度虽然都大于0.9,但红砂根系并不是完全通过这几种机理适应干旱,而是发生了一系列适应性的生理变化,以提高其根系的抗旱性。

The physiological responses of seedling roots to drought stress were investigated in the desert plant Reaumuria soongorica from two provenances： highly drought resistant （Wuwei） and weakly drought resistant （Lanzhou）. Under drought stress, root vigor, relative permeability of plasma （RPP）, contents of proline （Pro）, soluble sugars （SS）, soluble protein （SP）, malondialdehyde （MAD） and activities of superoxide dis mutase （SOD）, peroxidase （POD） and catalase （CAT）were measured with two-year nursery stocks. Grey cor relative analysis was used to analyse drought resistance and its correlation with indexes of roots. Root vigor de creased significantly under drought stress, while RPP and the contents of MDA, Pro, SS and SP, the activities of SOD, POD and CAT of roots increased significantly. Germplasm of highly drought-resistant provenance （Wuwei） was more sensitive to drought stress than germplasm of weakly drought-resistant provenance （Lanzhou）. The grey correlative degrees for root vigor, RPP and Pro and drought resistance were greater than 0.9. However, R. soongorica enhanced drought resistance through a wider series of physiological variations, beyond these three.