Dynamic of Physiology and Biochemistry during Wild Rhododendron scabrifolium Cutting Propagation | 糙叶杜鹃扦插生根过程中生理生化分析

Chinese. 以野生糙叶杜鹃半木质化茎段为试材,采用植物生长激素KNAA和KIBA对插穗进行处理,测定不同生根期内源激素IAA,GA3,ZR,ABA,以及茎段扦插过程中可溶性糖、全氮含量和相关抗氧化酶活性变化。结果表明：2000mg・L-1 KNAA＋2000mg・L-1 KIBA处理对插条生根具有显著影响,处理后的插穗生根率达到78.65%。在扦插生根过程中,较高浓度的内源IAA含量有利于根原基分化形成,GA3含量上升与插穗愈伤组织的诱导、不定根的形成呈正相关性,低水平的ABA更有利于糙叶杜鹃扦插生根;插穗在根原基分化和愈伤组织形成时期需要消耗一定的仍ZR;在生根过程中IAA/ABA比值较小,这可能是糙叶杜鹃扦插难生根的主要原因之一;插穗在生根过程中可溶性糖含量的增加、氮素含量的降低均有利于插穗不定根的生成。在扦插生根过程中氧化酶活性呈规律性变化,SOD,POD,PPO活性在愈伤组织诱导期上升,愈伤组织形成后略有下降,其中POD,PPO活性在不定根的形成期上升;生根后期糙叶杜鹃的CAT活性维持在较高的水平。

English. To establish a commercial feasible cutting propagation system of wild Azalea （ Rhododendron scabrifolium） , physiological mechanisms during the rooting of R. scabrifolium cutting propagation were investigated. Semi-hard wood stems of R. scabrifolium were collected and treated by KNAA and KIBA. Contents of endogenous hormones IAA, GA3 , ZR, and ABA were measured during the rooting period, and soluble sugar, total nitrogen content and the oxidase activity were also determined in stems during cuttings. The results indicated that KNAA 2 000 mg・ L. 1 ＋ KIBA 2 000 mg・ L. 1 had a significant effect on rooting and resulted in the highest rooting rate of 78.65%. During the rooting process, the higher concentration of endogenous IAA favored the formation of root primodia, GA3 content showed a positive correlation with the cuttings callus induction and adventitious root formation, and low levels of ABA should promote rooting of cuttings. Endogenous ZR was needed for root primodium differentiation and callus formation. IAA / ABA ratio was smaller in the process of rooting, which might be one of the reasons that R. scabrifolium cuttings usually are difficult to root. The increase in soluble sugar content and reduction of nitrogen concentrations were both conducive to the generation of cuttings adventitious roots. Oxidase activity changed regularly in the process of cuttings rooting. The activity of SOD, POD, and PPO increased in the callus induction period, and slightly decreased after callus formation. POD and PPO activity in the root, increased at adventitious root formation stage; POD and PPO activity increased in the adventitious root formation period, and CAT activity remained at a high level after the root formation.