一氧化氮和过氧化氢对地被菊扦插生根的影响

 以地被菊(Dendranthema morifolium ) 品种‘北国之春’为试验材料, 研究了一氧化氮(NO)和过氧化氢(H₂O₂ ) 对其插穗生根的影响以及生根过程中插穗叶片超氧化物岐化酶(SOD) 、过氧化物酶( POD) 、多酚氧化酶( PPO) 活性以及酚类物质含量的变化。结果表明, 外源NO和H₂O₂可促进地被菊插穗生根以及根的生长, 且表现出明显的浓度效应。促进生根最适硝普纳( SNP, NO供体) 和H₂O₂的浓度分别为50和200μmol·L ^-1。同时, SNP和H₂O₂共同处理的地被菊插穗生根率显著高于SNP或H₂O₂单独处理, 说明NO和H₂O₂在地被菊插穗生根过程中具有协同诱导效应。另外, 相比对照, SNP、H2O2和两者共同处理插穗叶片的SOD和PPO活性显著提高。而SNP、H₂O₂和两者共同处理比对照分别具有更低的POD活性和酚类物质含量, 且SNP +H₂O₂处理的POD活性和酚类物质含量低于SNP或H₂O₂单独处理。综合以上结果可知, 50μmol·L ^-1 SNP和200μmol·L ^-1H₂O₂处理可以提高插穗叶片SOD和PPO活性, 降低POD的活性和酚类物质的含量, 从而促进插穗生根和根的生长。

Effects of Nitric Oxide and Hydrogen Peroxide on Rooting of Ground-cover Chrysanthemum Cuttings

Ground-cover chrysanthemum (Dendranthema morifolium 'Beiguozhichun') was used to understand the effects of nitric oxide (NO) and hydrogen peroxide (H_2O_2) on rooting of plant cuttings and the changes of activities of superoxide dismutase (SOD), peroxidase (POD) and polyphenol oxidase (PPO) and the total polyphenol content of cutting leaves. The results showed that the effects of exogenous H_2O_2 or NO on rooting of ground-cover chrysanthemum cuttings was dose dependent, with a maximal biological response at 200 μmol·L~(-1)H_2O_2 or 50 μmol·L~(-1) NO donors SNP. At the same time, the rooting percentage of cuttings treated with both SNP and H_2O_2 was significantly higher than that of cuttings treated with SNP or H_2O_2 alone,which suggested that there might exist synergistic action between H_2O_2 and NO on mediating rooting. Additionally, compared with the control, SNP, H_2O_2 and SNP + H_2O_2 treatments might significantly increase the activities of SOD and PPO of ground-cover chrysanthemum cuttings leaves. However, the activities of POD and the total polyphenol content were significantly higher in control than in other treatments during rooting.Moreover, lower POD activities and polyphenol content were attained in SNP + H_2O_2 treatment than in SNP or H_2O_2 treatment alone. Together, these results indicated that 50 μmol·L~(-1) SNP and 200 μmol·L~(-1) H_2O_2 treatments enhanced rooting and root growth synergistically and independently by stimulating the activities of SOD and PPO enzymes, and simultaneously by repressing POD activities and the production of polyphenol.