Cd胁迫对紫花苜蓿种子发芽及幼苗生理生化特性的影响  

Seed Germination and Physiological and Biochemical Characteristics of Alfalfa under Cadmium Stress

作　　者：尹国丽[1,2] 师尚礼[1,2] 寇江涛[1,2] 周万海[1,2] 陈本建[1,2] 

机构地区：[1]甘肃农业大学草业学院,兰州730070 [2]草业生态系统教育部重点实验室,甘肃省草业工程实验室,中-美草地畜牧业可持续研究中心,兰州730070

出　　处：《西北植物学报》2013年第8期1638-1644,共7页Acta Botanica Boreali-Occidentalia Sinica

基　　金：农业部行业专项(201003023);国家现代牧草产业技术体系建设专项(CARA-35);全国草种质资源保种(NB2130135)

摘　　要：以‘甘农3号’紫花苜蓿(Medicago sativa L.cv.‘Gannong 3’)品种为试验材料,研究不同浓度Cd胁迫对紫花苜蓿种子萌发及幼苗生理生化特性的影响。结果显示:(1)Cd胁迫显著抑制紫花苜蓿种子萌发及幼苗生长,种子发芽势、发芽率及幼苗的胚芽长、胚根长和干重均随着Cd处理浓度提高显著降低,且对发芽势的抑制作用大于发芽率,对胚根生长的抑制作用大于胚芽。(2)Cd胁迫第4d时,萌发种子中蛋白水解酶的活性受到显著抑制,可溶性蛋白和可溶性糖含量显著降低。(3)Cd胁迫第10d时,随着Cd胁迫浓度的增加,苜蓿幼苗的超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、愈创木酚过氧化物酶(GPX)活性均先升高后降低,过氧化氢酶(CAT)活性持续下降,超氧阴离子自由基产生速率、H2O2含量和丙二醛(MDA)含量均显著增加。研究表明,低浓度Cd胁迫下,苜蓿幼苗抗氧化系统清除活性氧的能力上升,高浓度Cd胁迫下,苜蓿幼苗抗氧化系统活性下降,膜脂过氧化程度加剧,活性氧的过量积累是Cd伤害苜蓿幼苗和其生物量下降的主要原因。Seeds of Medicago sativa L.cv.‘Gannong No.3’ were used as test material to study the effects of different cadmium concentrations on seed germination and physiological and biochemical characteristics.The results showed that：（1）Cadmium significantly inhibited seed generation and bud growth.The germination energy,germination rate,bud and hypocotyl lengths,and dry weight decreased significantly.The inhibition effect on germination energy was found stronger than that on germination rate,and on hypocotyl length was found stronger than that on bud.（2）On the 4th day of germination,proteolytic enzyme activity in seeds was significantly inhibited,together with the significant decrease of soluble protein and soluble sugar contents（P〈0.05）.（3）On the 10th day of germination,the activities of SOD,APX and GPX increased firstly and then decreased,CAT activity decreased continuously,while superoxide radical generation rate,H2O2 and MDA contents increased significantly,indicating that low cadmium concentration promoted the scavenging capacity of anti-oxidative system in seedlings while under high cadmium concentration,the anti-oxidative system activity decreased,and lipid peroxidation accelerated.The excessive accumulation of reactive oxygen was the main reason for seedling damage and biomass decrease.

关 键 词：镉胁迫 紫花苜蓿 种子萌发 幼苗生长 活性氧 

分 类 号：Q945.78[生物学—植物学]