播期、品种对沙地紫花苜蓿抗氧化特性与越冬率的影响

Effects of Sowing Dates and Varieties on Antioxidant Characteristics and Overwintering Rate of Alfalfa in Sandy Land

为探讨不同播种时期紫花苜蓿(Medicago saliva L.)根颈抗氧化特性变化规律及其与越冬的关系,本试验选择3个紫花苜蓿品种(骑士T、公农1号、擎天柱),于2017年7月1日开始,每5天播种一期,播种至8月15日。2017年10月11日(土壤冻融交替期)、11月11日(土壤封冻期)取样测定紫花苜蓿根颈中超氧化物歧化酶(Superoxide dismutase,SOD)、过氧化物酶(Peroxidase,POD)、过氧化氢酶(Catalase,CAT)活性和丙二醛(Malondialdehyde,MDA)含量,翌年春季调查越冬率。结果表明:随着播种时期的推迟,3个紫花苜蓿品种的越冬率均明显下降,紫花苜蓿根颈中CAT,POD,SOD酶活均呈下降趋势;越冬率与10月11日紫花苜蓿根颈的SOD酶活性及11月11日根颈的POD酶活性呈显著正相关关系,与10月11日和11月11日根颈的MDA含量呈负相关关系。研究认为,紫花苜蓿根颈中SOD,POD,CAT 3种抗氧化酶是其适应低温的关键酶,在阿鲁科尔沁地区,7月21日之前播种可有效提高紫花苜蓿越冬率。

In order to explore the changes of antioxidant characteristics of alfalfa root neck at different sowing stages and their relationship with overwintering.Three alfalfa varieties(Knight T,Gongnong 1 and Optimus Prime)were selected to sow every five days from July 1,2017 to August 15.The contents of Malondialdehyde and the activities of Superoxide dismutase,Peroxidase and Catalase in alfalfa root neck were measured on October 11,2017(soil freezing-thawing alternation period)and November 11,2017(soil freezing period).The overwintering rate was investigated in spring of the second year.The results showed that with the delay of the sowing time,the overwintering rate of three alfalfa varieties decreased significantly,and the activities of CAT,POD and SOD in alfalfa root neck showed a downtrend.The overwintering rate was positively correlated with SOD activity of alfalfa root neck on October 11 and POD activity in root neck on November 11,but negatively correlated with MDA content of alfalfa root neck on October 11 and November 11.In summary,SOD,POD and CAT in alfalfa root neck are the key enzymes to adapt to low temperature.In Arukerqin region,sowing before July 21 can effectively improve the overwintering rate of alfalfa.