施加外源IBA对南川大茶树扦插生根和茶树生长素应答因子(CsARFs)mRNA表达的影响

Effect of Applying Indole-3-butyric Acid on the Rooting of Camellia sinensis Cuttings and the mRNA Expression of Auxin Response Factor (CsARFs)

【目的】研究施加吲哚-3-丁酸(indole-3-butyric acid, IBA)对南川大茶树(Camellia sinensis)扦插生根能力、相关生理指标和茶树生长素应答因子(CsARFs)表达的影响。【方法】施用不同质量浓度的IBA (0、20、40、80、160和320 mg/L)对南川大茶树插穗进行处理,在扦插后30、60、90和120 d,分别测定根部吲哚乙酸氧化酶(IAAO)、过氧化物酶(POD)和多酚氧化酶(PPO)活性,150 d时检测生根能力。同时,测定80 mg/L IBA处理组扦插30、60、90和120 d后,根部CsARFs基因mRNA表达量。【结果】20、40、80和160 mg/L的IBA具有促进生根作用,并伴随着POD、PPO活性增加和IAAO活性降低,而320 mg/L IBA显著抑制生根(P<0.05)。在80 mg/L处理组中,生根数、愈伤诱导率、生根率、最长根长和平均根长效果最优;且除120 d外,与对照组相比,CsARF 2-1、2-2、3-1、3-2、8、9和11的mRNA水平显著上调。【结论】南川大茶树扦插时IBA的最佳质量浓度为80 mg/L。

[Purpose]To study the effect of indole-3-butyric acid(IBA) on Nanchuan tea(Camellia sinensis) rooting capacity, the physiological changes during the rooting process and the mRNA expression of CsARFs gene.[Method]The cuttings were treated with the concentrations of IBA(0,20, 40, 80, 160 and 320 mg/L). The root capacities were assessed at the end of rooting period,the IAA-oxidase(IAAO) activity, peroxidase(POD) activity and polyphenol oxidase(PPO) activity were determined at 30, 60, 90 and 120 days after planting(DAP). The CsARFs gene expression in the roots was detected at 30, 60, 90 and 120 days with the 80 mg/L IBA-treatment.[Result]IBA had a positive effect on the rooting at the mass concentration of 20, 40, 80 and 160 mg/L IBA, which accompanied with increased POD activity and PPO activity, and decreased IAAO activity, but the 320 mg/L IBA caused a significant reduction of rooting compared with the control(P<0.05). Among of the treatments, the cuttings treated with 80 mg/L IBA had the highest number of roots(NR), callus percentage(CP) and rooting percentage(RP), and higher length of the longest root(LLR) and the mean root length(MRL). Additionally, the mRNA expressions of CsARF 2-1, 2-2, 3-1, 3-2, 8, 9 and 11 were up-regulated in the roots treated by 80 mg/L IBA except 120 days, suggesting these genes involved in promoting rooting process.[ Conclusion]The optimal IBA mass oncentration was 80 mg/L for cutting of Nanchuan tea(C. sinensis).