苜蓿与无芒雀麦单混播后越冬期根系生理指标的变化及其与抗寒性的关系

[目的]研究紫花苜蓿与无芒雀麦单混播后越冬期根系MDA含量及抗氧化酶活性的变化及其与抗寒性的关系。[方法]通过对4种抗寒性不同的紫花苜蓿品种与无芒雀麦单、混播处理后,测定苜蓿根系在整个越冬期间的丙二醛(MDA)含量、超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性的变化。[结果]苜蓿单播及与无芒雀麦混播后根系MDA含量随温度的变化呈升高、降低、升高的变化趋势;CAT活性随着自然温度的下降而增加,翌年春随着温度的回升而降低;SOD和POD的活性则随温度的大幅下降呈增加趋势,随着温度继续下降和寒冷时间的延长而有所下降,翌年又随苜蓿返青而有所提高。同一品种不同处理酶活性表现为混播高于单播。运用隶属函数法进行抗寒性综合评判,发现各处理抗寒性从强到弱依次为:Wega7F+无芒雀麦、Wega7F、WL319HQ+无芒雀麦、WL319HQ、驯鹿+无芒雀麦、驯鹿、敖汉+无芒雀麦、敖汉。[结论]该研究结果对于我国北方干旱寒冷地区苜蓿抗寒育种及栽培利用具有重要意义。

Study on the Changes of Physical Indices of Root in Wintering Period with Single Sowing of Medicago sativa and Its Mixed-sowing Treatment with Bromus inermis and Their Relations with Cold Resistance

Objective] To study the changes of MDA content and anti-oxidative enzyme activity of root in wintering period with single sowing of M.sativa and its mixed-sowing treatment with B.inermis and their relations with cold resistance.[Method] Taking four kinds of M.sativa (We-ga7F, Xunlu, Aohan and WL319HQ) and one kind of B.inermis as experimental materials, the changes of MDA, SOD, POD and CAT contents in roots of M.sativa during whole wintering period were measured.[Result] The content of MDA change showed up-down-up change trend with temperature by single sowing of M.sativa and its mixed-sowing treatment with B.inermis.The CAT activity of root increased with air tempera-ture decline, and decreased with air temperature rise in next spring .The SOD and POD activities firstly increased then decreased at lower tem-perature, and finally increased again in the following spring.Enzymes activities by mixed sowing were all higher than single sowing.Membership function analysis showed the order of cold-resistance of M.sativa varieties were Wega7F+B.inermis>Wega7F>WL319HQ +B.inermis>WL319HQ>Xunlu+B.inermis>Xunlu>Aohan+B.inermis>Aohan.[Conclusion] It had important significance for cold resistance breeding and cultivation of M.sativa in cold region of North China.