继代培养温度对牡丹试管苗增殖及后续生根的影响

Effect of subculture temperature on the in vitro shoot multiplication and subsequent rooting of tree peony

关键词:  ‘皇冠’牡丹，继代培养温度，不定根，生理指标，相关性分析

Key words:  Paeonia × lemoinei ‘Yellow Crown’, subculture temperature, adventitious root, physiological indexes, correlation analysis

摘要:

为探究继代培养温度对‘皇冠’牡丹（Paeonia × lemoinei ‘Yellow Crown’）试管苗增殖、生根的影响及其生理机制，该研究设置16、20、24、28 ℃四个温度处理，试管苗培养40 d后测定增殖指标，并统一转入生根培养并评估生根表现，同时分析内源激素生长素（IAA）、脱落酸（ABA）、玉米素（ZR）和赤霉素（GA?）的含量，超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）的活性、总酚含量及叶片显微结构。结果表明：（1）24 ℃为适宜的继代培养温度，试管苗增殖系数达2.12，芽质量优良（+++），后续生根率达39.05%，根系发育良好。（2）相关性分析显示，IAA含量、IAA/ABA比值与生根率呈极显著正相关（r 分别为0.82, 0.91），ABA含量、SOD活性与生根率呈极显著负相关（r 分别为-0.83, -0.83）；茎叶总酚含量与根长显著正相关（r = 0.71），气孔长轴长度与生根率显著负相关（r = -0.68）。该研究结果表明继代培养温度通过调控内源激素平衡、抗氧化酶活性及叶片气孔形态等生理过程，综合影响牡丹试管苗增殖与生根，24 ℃可同步优化其快繁效果，为牡丹高效微繁殖提供理论依据。

Abstract:

This study aimed to investigate the effects of subculture temperature on shoot multiplication and subsequent rooting of Paeonia × lemoinei 'Yellow Crown' plantlets in vitro, and to explore the underlying physiological mechanisms. Four temperature treatments (16, 20, 24, and 28 ℃) were applied during the subculture stage. After 40 days, proliferation parameters were measured, and plantlets were subsequently transferred to a rooting medium to evaluate rooting performance. Physiological analyses included endogenous hormones (IAA, ABA, ZR, GA?), antioxidant enzyme activities (SOD, POD, CAT), total phenolic content, and leaf microstructure. The results showed that: (1) 24 ℃ was the optimal temperature, yielding the highest proliferation coefficient (2.12), excellent shoot quality (+++), and a subsequent rooting rate of 39.05% with well-developed roots. (2) Correlation analysis revealed highly significant positive correlations of IAA content and IAA/ABA ratio with rooting rate (r = 0.82, 0.91), while ABA content and SOD activity were highly significantly negatively correlated with rooting rate (r = -0.83, -0.83). Total phenols content in stems and leaves was significantly positively correlated with root length (r = 0.71), and stomatal long-axis length was significantly negatively correlated with rooting rate (r = -0.68). These findings indicate that subculture temperature comprehensively influences proliferation and rooting in tree peony by modulating endogenous hormone balance, antioxidant enzyme activity, and stomatal morphology. The 24 ℃ treatment simultaneously optimized both multiplication and subsequent rooting, providing a theoretical basis for efficient micropropagation of tree peony.