淹水对紫花苜蓿南北方品种抗氧化酶和无氧呼吸酶的影响

Effect of waterlogging on antioxidant and anaerobic respiratory enzymesin Medicago sativa varieties from southern and northern China

以紫花苜蓿南方育成品种渝苜1号和北方地方品种新疆紫泥泉为材料,在幼苗长出4片真叶时进行淹水处理,在淹水的第10天测定植株的生物量,并分别在淹水的第0,2,4,6,8,10天测定叶片中的丙二醛(MDA)含量以及叶片抗氧化酶和根系无氧呼吸酶的活性,以探明两个品种对淹水胁迫的耐受性差异及其生理响应机制。结果表明,淹水胁迫使紫花苜蓿的生物量减少,但与新疆紫泥泉相比,渝苜1号生物量的降幅小。淹水时渝苜1号叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)等抗氧化酶活性比新疆紫泥泉的高,而叶片MDA含量比新疆紫泥泉的低;根系无氧呼吸酶活性在淹水胁迫中均增强,但渝苜1号的乙醇脱氢酶(ADH)和丙酮酸脱羧酶(PDC)活性增加明显,乙醇发酵更强;而新疆紫泥泉的乳酸脱氢酶(LDH)的活性增加更为突出,乳酸发酵强。淹水影响紫花苜蓿正常生长,但南方品种渝苜1号比北方品种新疆紫泥泉对淹水胁迫更具耐受性,因为前者具有比较高的抗氧化酶活性和比较强的乙醇发酵途径,有利于增强植株抗淹水胁迫能力。

Two Medic na）, were compared. ago sativa varieties, Yumu No. 1 （southern China） and Xinjiangziniquan （northern Chi- Six waterlogging treatments 0, 2, 4, 6, 8 and 10 days of waterlogging were imposed on seedlings at the 4-leaf stage. The malondialdehyde （MDA） content, superoxide dismutase （SOD）, peroxidase （POD） and catalase （CAT） activity in the leaves and lactate dehydrogenase （LDH）, pyruvate （PDC） and alco hol dehydrogenase （ADH） activity in the roots were evaluated in all treatments. Biomass was measured after 10 days of waterlogging. Waterlogging stress reduced the biomass of both varieties but Yumu No. 1 was less af- fected than Xinjiangziniquan. The activities of SOD, POD and CAT in leaves of Yumu No. 1 were higher than those of Xinjiangziniquan under waterlogging stress, but the MDA content in the leaves was lower than that of Xinjiangziniquan. The activity of respiratory enzymes in the roots was influenced by waterlogging In Yumu No. 1 ADH and PDC activity increased more than LDH activity with stronger alcohol dehydrogenaseactivity, while in Xinjiangziniquanwaterlogging resulted in increased LDH and lactic dehydrogenase activity. It was con cluded that the greater tolerance of waterlogging observed dant enzyme and anaerobic respiratory enzyme activity. in Yumu No. 1 was primarily due to higher antioxi-dant enzyme and anaerobic respiratory enzyme activity.