| 摘要: |
| 【目的】研究牡丹试管苗生根期间相关酶活性和内源生长素吲哚乙酸（IAA）含量的变化，以及生根期间茎基部内源IAA的分布，为牡丹快速繁殖提供理论依据。【方法】以牡丹试管苗‘凤丹白’为试验材料，以WPM+WPM（Ca2+）+聚乙烯吡咯烷酮（PVP）1 g/L+糖30 g/L+植物凝胶2 g/L(pH=5.8)为生根培养基，研究外源添加不同质量浓度（0（CK），1，2，3和4 mg/L）IAA对其生根的影响，并测定牡丹试管苗生根期间茎基部过氧化物酶（POD）、多酚氧化酶（PPO）、吲哚乙酸氧化酶（IAAO）活性及内源IAA含量的变化，同时对牡丹试管苗生根期间茎基部进行细胞学观察和IAA免疫荧光定位分析。【结果】牡丹试管苗在外源添加3 mg/L IAA的生根培养基中生根率最高（52.00%）、生根指数最大（12.47），且显著高于其他处理；CK处理的生根率、平均最大根长和生根指数均低于其他处理。在牡丹试管苗生根期间，其茎基部的POD、PPO和IAAO活性始终处于波动变化中；内源IAA含量则呈现先升高后降低的变化趋势，在生根培养5 d时达到最大值62.80 ng/g。细胞学观察结果显示，牡丹试管苗根原基诱导期为接入生根培养基后的3～5 d，对于生根培养基中添加3 mg/L IAA的处理，其试管苗茎基部POD和PPO活性均在培养3 d时达到峰值，IAAO活性在培养3～4 d处于显著下降趋势，而内源IAA含量在培养3～5 d处于升高趋势。免疫荧光定位分析表明，在牡丹试管苗生根期间，内源IAA以茎基部维管束中分布最多，且一直作用于根原基形成和伸长的部位，荧光信号强弱与其含量相一致。【结论】在牡丹试管苗生根期间，外源添加IAA后，高活性的POD、PPO及低活性的IAAO有助于根原基的发生，内源IAA在根原基的积累与牡丹试管苗不定根的发生密切相关。 |
| 关键词: 牡丹 组织培养 IAA 生根培养 酶活性 免疫荧光技术 |
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| 基金项目:河南省科技创新人才计划项目（174200510004）；河南省科技攻关项目（182102110033，202102110083）；国家自然科学基金项目（31870698） |
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| Changes of endogenous IAA and related enzyme activities during rooting of Paeonia suffruticosa in vitro |
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SHANG Wenqian,WANG Zheng,HE Songlin,et al
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| Abstract: |
| 【Objective】The enzyme activities,endogenous hormones and IAA localization during rooting period of Paeonia suffruticosa in vitro were studied to provide basis for rapid propagation of tree peony.【Method】In vitro cultivars of tree peony (Paeonia suffruticosa) ‘Feng Dan Bai’ were tested using WPM+WPM (Ca2+) +polyvinyl pyrrolidone (PVP) 1 g/L+sugar 30 g/L+Gellan gum 2 g/L (pH=2.8) as rooting medium.The effects of IAA at different concentrations (0 (CK),1,2,3 and 4 mg/L) on rooting were studied,and changes in peroxidase (POD),polyphenol oxidase (PPO) and indoleacetic acid oxidase (IAAO) activities and content of endogenous IAA were measured. Cytological observation and IAA immunofluorescence localization were also performed.【Result】The highest rooting rate (52.00%) and rooting index (12.47) were obtained in the rooting medium supplemented with 3 mg/L IAA,which were significantly higher than other treatments.The rooting rate,average maximum root length,and rooting index of CK were lower than other treatments.During rooting of tree peony in vitro,the activities of POD,PPO and IAAO at the base of stem fluctuated,while the content of endogenous IAA showed a trend of increasing first followed by decrease with a maximum of 62.80 ng/g on the 5th day of rooting.The cytological observation results showed that the root primordium induction period of the tree peony in vitro was the 3rd to 5th day after rooting medium was inserted.For the treatment with 3 mg/L IAA,peak values of POD and PPO activities were reached on the 3rd day,IAAO activity showed a downward trend from the 3rd to 4th day,while endogenous IAA content increased from the 3rd to 5th day.Immunofluorescence localization analysis showed that endogenous IAA was mostly distributed in the vascular bundle of stem base during rooting,and it acted on root primordium formation and elongation.【Conclusion】High activities of POD and PPO and low activity of IAAO after IAA application were helpful to the occurrence of root primordium.The accumulation of endogenous IAA in root primordium was closely related to the adventitious roots of tree peony in vitro. |
| Key words: Paeonia suffruticosa tissue culture IAA rooting cultivation enzyme activity immunofluorescence |
