中文摘要：

以寒敏感的普通狗牙根、海岸狗牙根和抗寒的新农1号狗牙根、喀什狗牙根为供试材料，研究外源脱落酸（0mg·L^-1、5mg·L^-1、15mg·L^-1、25mg·L^-1）在4oC低温处理下（处理时间24h、72h）对叶片相对电导率（EC）、丙二醛（MDA）含量、超氧化物歧化酶（SOD）活性、过氧化氢酶（CAT）活性、过氧化物酶（POD）活性的影响。结果表明：与CK2（喷水、常温培养）相比，4℃低温处理24h、72h，无论是否喷施外源脱落酸，狗牙根均表现为EC增大，MDA含量增加；但与CK1（喷水、4℃低温处理）相比，喷施外源脱落酸可以诱导狗牙根细胞EC、MDA含量降低，促进SOD活性、POD活性、CAT活性的进一步增加，保护膜系统的完整性，增强其对低温的适应。综合分析认为，抗寒狗牙根的适宜外源脱落酸喷施浓度为15mg·L^-1，寒敏感狗牙根为5mg·L^-1更有利于其对低温的适应。随着低温处理时间的延长，抗寒狗牙根SOD活性增加率、MDA含量降低率明显高于寒敏感狗牙根，说明SOD酶活性不同可能是狗牙根抗寒性差异的原因之一。

英文摘要：

Taking sistant bermudagrass cold-sensitive bermudagrass （common bermudagrass and coastal bermudagrass） and cold-re- （ Xinnong No. 1 and Kashgar bermudagrass） as the test materials, the effect of ABA （0 mg ·L^-1 ,5 mg ·L^-1, 15 mg ·L^-1 and 25 mg ·L^-1） on relative electric conductivity （EC）, malondialdehyde content （MDA）, superoxide dismutase activity （SOD）, catalase activity （CAT） and peroxidase activity （POD） of leaves under 4 ℃ for 24 and 72 hours were studied. The results showed that the EC and MDA of bermudagrass were in- creased compared with the situation of CK2 （water spray and cultivation under room temperature） regardless of spraying ABA or not. But compared with the situation of CK1 （water spray and cultivation under 4 ℃ ）, spray of ABA could induce the decrease of EC and MDA of bermudagrass, promote the increase of SOD activity, CAT activ- ity and POD activity, protect the integrity of membrane system, and enhance the adaptation to low temperature. Af- ter carrying out a comprehensive analysis, it was considered that the suitable ABA concentration for cold-resistant bermudagrass was 15 mg ·L^-1, that for cold-sensitive bermudagrass was 5 mg ·L^-1 under the consideration of a- dapting low temperature. With prolonging the time of low temperature, the increase rate of SOD activity and the de- crease rate of MDA of cold-resistant bermudagrass were obviously higher than that of cold-sensitive bermudagrass, which revealed that the difference of SOD activity was one of the reasons to cause the difference of cold resistance.