积雪覆盖对苜蓿越冬及返青生长的影响

Effects of Snow Cover on Alfalfa Over-wintering and Turning Green

以龙牧806、公农1号、敖汉、Wega7F、WL319HQ、草原3号为材料,以自然降雪量为对照,设置无降雪、30%自然降雪量、70%自然降雪量3个处理,测定苜蓿越冬前后根系营养物质含量、根系形态特征、抗氧化酶活性及返青率、返青后的株高和干鲜重,结果表明：覆盖积雪是紫花苜蓿安全越冬返青的保障,54.5~77.9cm降雪量是安全越冬的适宜积雪厚度;紫花苜蓿通过增强根颈发育、提高根系营养物质及抗氧化酶活性来提高越冬性能,且其受降雪量影响较大,70%自然降雪量处理的根颈直径最大,较越冬前高21%,全氮和可溶性糖含量分别提高61%、60%,可溶性蛋白含量降低8%,SOD、CAT活性分别降低20%与9%;不同苜蓿的越冬性能存在差异,草原3号、Wega7F具有较高的产草量及耐寒能力。

In order to investigate the effect of snow cover on alfalfa overwintering and turning green,6different alfalfa varieties（including Longmu 806,Gongnong No.1,Aohan,Wega 7F,WL319 HQ,Caoyuan No.3）were used as plant materials.There were 4treatments in this study including snow-cover of0,30%,70%and natural snow-cover（as control）.Nutrient content of root,root morphological characteristics and antioxidant enzymes activity were measured before and after overwintering period.The rate of plant returning green,plant height,dry weight and fresh weight were also measured after turning green.The results showed that the snow cover was the safety guarantee for alfalfa overwintering and turning green.The 54.5~77.9cm snowfall was the optimum thickness for safe overwintering.Alfalfa improved the overwintering ability by enhancing the root neck development,root nutrients and antioxidant enzyme activity,and it was affected by snow cover.The diameter of alfalfa root neck was maximal in the 70% of natural snow cover,which improved by 21%than that before overwintering.In addition total nitrogen and soluble sugar increased by 61% and 60%respectively,soluble protein reduced by 8%,SOD and CAT reduced by 20% and 9% respectively than that before overwintering under 70% of natural snow-cover.There were differences in overwintering ability among 6different alfalfa varieties,Caoyuan No.3and Wega 7Fhad higher yield and stronger overwintering ability.