Male sterility is very important in the utilization of hybrid heterosis in Platycodon grandiflorus.The physiological and biochemical mechanisms of male sterile material,the contents of soluble sugar,free proline,soluble protein,and the activity of superoxide dismultase (SOD),peroxidase (POD),and catalase (CAT) in flower buds at different developmental stages of male sterile lines and viable lines were investigated.The results showed that: 1) The contents of soluble sugar,free proline,and soluble protein in flower buds at different developmental stages of male sterile lines was lower than those of viable lines.Free proline irreversibly increased in male sterile buds as flower buds developed,but its content in viable buds was lower.2) The variation in activity of reactive oxygen species and scavenger enzymes was almost same between sterile buds and viable buds during bud development,whereas activities of SOD,POD,and CAT was higher in male sterile buds than in viable buds.3) The malondialdehyde (MDA) content of male sterile buds was higher than that of viable buds at all times.High activity of reactive oxygen species,scavenger enzymes,high content of MDA and low content of free proline may be the results of male sterility in P.grandiflorus.%在桔梗花器官发育过程中,取不同发育时期的桔梗花蕾,测定其可溶性糖含量、游离脯氨酸含量、可溶性蛋白质含量、超氧化物歧化酶活性、过氧化物酶活性、过氧化氢酶活性和丙二醛含量,比较分析桔梗不育材料与可育材料花蕾发育过程中生理生化特性差异.结果表明,1)花前花蕾发育的各阶段,桔梗不育花蕾可溶性糖含量、游离脯氨酸含量和可溶性蛋白质含量均低于相应可育花蕾,其中尤以游离脯氨酸表现最为明显,随开花前花蕾的发育,可育花游离脯氨酸含量不断升高,而不育花蕾中其含量较低且变化很小.2)与可育花蕾相比,不育花蕾在发育过程中SOD、POD、CAT活性变化趋势基本相同,但其活性明显高于可育花蕾.3)在桔梗花蕾发育的各阶段,不育花丙二醛含量均明显高于相应可育花.桔梗不育花蕾(开花前)生长发育过程中,体内活性氧代谢紊乱、丙二醛积累及游离脯氨酸等“物质代谢损亏”可能是引起桔梗雄性败育的原因.
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