红毛五加不定根形成过程中形态及生理生化特征

Morphological,physiological and biochemical characterization during the formation of adventitious roots in Eleutherococcus giraldii

本研究对红毛五加(Eleutherococcus giraldii)不定根发育过程中的形态和生理生化变化规律进行分析,为提高红毛五加扦插技术提供理论支撑。以红毛五加当年生扦插条为试材,对生根过程中不定根形态、营养物质含量、抗氧化酶活性、植物激素含量等进行测定。结果显示,红毛五加插穗基部未发现潜伏根原基,属诱导生根型,扦插生根过程中既有皮部生根,又有愈伤组织生根,属于混合生根型;随着不定根的形成,可溶性蛋白、可溶性糖的含量在愈伤组织未生成期(Ⅰ期)、愈伤组织生成期(Ⅱ期)、不定根发生期(Ⅲ期)均较低,在根伸长期(Ⅳ期)分别增加至最高;超氧化物歧化酶(SOD)活性在Ⅰ~Ⅳ期持续升高,过氧化物酶(POD)和过氧化氢酶(CAT)活性呈现先升高后降低的趋势;插穗皮部脱落酸(ABA)、赤霉素(GA3)含量在Ⅱ期减少,随后趋于平稳,吲哚乙酸(IAA)含量在Ⅲ期减少,随后趋于平稳。玉米素核苷(ZR)含量持续减少。IAA/ABA在前三个时期较高,在Ⅳ期下降。综上结果表明,红毛五加属于混合生根型,可溶性蛋白含量、可溶性糖含量、SOD活性升高有利于不定根的形成,POD、CAT的活性升高有利于愈伤组织的形成,少量的IAA、GA3有利于插穗基部的不定根分化。

This study analyzed the changing patterns of morphology,physiology and biochemistry during the development of adventitious roots of Eleutherococcus giraldii to provide theoretical support for improving its propagation by cutting technology.Using the annual cuttings of E.giraldii as the test material,the adventitious root morphology,nutrient content,antioxidant enzyme activity,and phytohormone content during the rooting process were measured.The results showed that no latent root primordia were found at the base of E.giraldii,which belonged to the induced rooting type,and the cuttings were rooted from both cortical and healing tissue,which belonged to the mixed rooting type.With the formation of adventitious roots,the content of soluble protein and soluble sugar was lower during the non-callus formation stage(phaseⅠ),callus formation stage(phaseⅡ),and adventitious root occurrence stage(phaseⅢ),and increased to the highest during the root extension stage(phaseⅣ).The activity of superoxide dismutase(SOD)continued to increase from phaseⅠto phaseⅣ,while the activities of peroxidase(POD)and catalase(CAT)showed a trend of first increasing and then decreasing.The content of abscisic acid(ABA)and gibberellin 3(GA3)in the bark of cuttings decreased in phase II and then stabilized,while the content of indole-3-acetic acid(IAA)decreased in phase III and then stabilized.The content of zeatin riboside(ZR)continued to decrease.IAA/ABA remained at a high level in the first three periods and decreased in the fourth period.Overall,the results indicate that E.giraldii belongs to the mixed rooting type.The increase of soluble protein content,soluble sugar content and SOD activity was conducive to the formation of adventitious roots,the increase of POD and CAT activities was conducive to the formation of callus,and a small amount of IAA and GA3 were conducive to the differentiation of adventitious roots at the base of cuttings.