Abstract:

In order to solve the dispute whether Horqin sandy land alfalfa (Medicago sativa) should be cut in late autumn and to determine the best cutting period, the antioxidant enzyme activity and proline content of 8 alfalfa varieties(‘Caoyua NO.2’, ‘Caoyuan NO.3’, ‘Dongmu NO.1’, ‘Nongjing NO.1’, ‘Nongjing NO.8’, ‘Zhaodong’, ‘Longmu NO.801’, ‘Gongnong NO.1’) cut in different periods of late autumn or without cutting were measured. The results showed that compared with cutting in late autumn early (October 1st),no cutting SOD activity of root neck of alfalfa significantly enhanced in the soil freezing and thawing period(P<0.05); Cutting in October 1st POD activity in the root neck of alfalfa was significantly higher than those without cutting and cutting late autumn (October 15th) POD activity of root neck (P<0.05); Cutting in October 1st POD activity of root neck of afalfa was significantly higher than that of no cutting and cutting late autumn(October 15th)(P<0.05);There was no significant change of CAT activity in the root neck of not cutting and cutting in different periods;Cutting in October 1st the content of MDA in root neck of alfalfa was significantly higher than that of no cutting and cutting in October 15th(P<0.05);No cutting of alfalfa the content of free proline in root neck was significantly higher than that of cutting in different periods(P<0.05); In the soil frozen period,no cutting of alfalfa the activity of SOD and POD in the root neck was significantly higher than that of in different periods of cutting (P<0.05);Cutting in October 1st the activity of CAT in root of alfalfa was significantly higher than that of not cutting and cutting in October 15th(P<0.05); Cutting in October 1st the content of MDA in root neck of alfalfa was significantly lower than that of no cutting and cutting in October 15th (P<0.05);Free proline content in root neck of no cutting alfalfa was significantly higher than that of cutting in October 1st (P<0.05).Conclusion:compared with cutting into the winter,the activity of SOD and POD in the root neck of non cutting alfalfa was enhanced,and the content of free proline was increased.So the ability of not cutting alfalfa to adapt to low temperature environment is strong.In the sensitive period of cutting to stimulate CAT activity of alfalfa root neck enhancement,but the activity of SOD and POD is low,the content of free proline decreased,so cutting alfalfa has low ability to adapt to low temperature environment.It is not recommended in the sensitive period of cutting.

Key words: Cutting treatment, Sandy alfalfa, Root neck, Antioxidant enzyme activity, Proline content

摘要：

为解决科尔沁沙地苜蓿（Medicago sativa）秋末是否应该刈割及最佳刈割时期的争议，本试验对秋末不同时期刈割处理和未刈割的8个苜蓿品种（‘草原2号’、‘草原3号’、‘东苜1号’、‘农菁1号’、‘农菁8号’、‘肇东’、‘龙牧801’、‘公农1号’）根颈中抗氧化酶活性及脯氨酸含量变化测定。结果表明：土壤冻融交替期，未刈割与秋末早割（10月1号）相比苜蓿根颈中SOD活性显著增强（P<0.05）；10月1号刈割苜蓿根颈中POD活性显著高于未刈割和秋末晚割（10月15号）苜蓿根颈中POD活性（P<0.05）；不同时期刈割和未刈割苜蓿根颈中CAT活性无显著变化；10月1号刈割紫花苜蓿根颈中MDA含量高于未刈割与10月15号刈割苜蓿根颈中含量；未刈割苜蓿根颈中游离脯氨酸含量显著高于不同时期刈割苜蓿根颈中含量（P<0.05）。土壤封冻期，未刈割苜蓿根颈中SOD、POD活性显著高于不同时期刈割根颈中SOD活性（P<0.05）；10月1号刈割苜蓿根颈中CAT活性显著高于未刈割和10月15号刈割苜蓿根颈中CAT活性（P<0.05），且MDA含量显著低于未刈割与10月15号刈割苜蓿根颈中含量（P<0.05）；未刈割苜蓿根颈中游离脯氨酸含量显著高于10月1号刈割根颈中含量（P<0.05）。研究结论为：进入寒冬，刈割与未刈割相比，未刈割苜蓿根颈中SOD、POD活性增强，游离脯氨酸含量增加，适应低温环境能力强，秋末敏感期刈割刺激苜蓿根颈中CAT活性增强，但SOD、POD活性较低，游离脯氨酸含量下降，适应低温环境能力弱，因此不建议秋末敏感期刈割。

关键词: 刈割处理, 沙地苜蓿, 根颈, 抗氧化酶活性, 脯氨酸含量