萘乙酸对紫楠幼苗根系形态和内源激素的调节效应

Regulation effects of naphthalene acetic acid on root morphologyand endogenous hormones of Phoebe sheareri seedlings

为探究不同浓度萘乙酸(NAA)对紫楠幼苗根系形态和内源激素含量的影响,明确NAA在紫楠幼苗根系发育中的调节作用,以同一母树同一枝条上采集的成熟紫楠种子萌发的幼苗为研究对象,设置浓度为0、25、50和75 mg·L^(-1)NAA处理,分析NAA对紫楠幼苗根系形态和内源激素含量的调控作用。结果表明,NAA处理抑制了紫楠幼苗主根生长,主根直径和根系总表面积得到增加,同时显著提高根系总生物量(P<0.05)。当NAA浓度为75 mg·L^(-1)时,紫楠幼苗根系总表面积和根系总长度达到最大;1级侧根数目、1级侧根总长度增加且达到最大。外源激素NAA显著提高紫楠幼苗根系反式玉米素(TZ)含量(P<0.05);随着NAA浓度升高,根系拓扑指数显著增大(P<0.05),紫楠根系向鱼尾形分支类型进化。浓度为75 mg·L^(-1)NAA处理可以显著提高紫楠幼苗根系生物量和TZ含量(P<0.05),同时显著降低根系内源激素脱落酸含量(P<0.05),促进根系TZ的合成积累,促进根系的发育。

To explore the effects of different concentrations of naphthalene acetic acid(NAA)on root morphology and endogenous hormone content of Phoebe sheareri seedlings and the regulatory effects of NAA on the root development of Phoebe sheareri seedlings,the germination seedlings of mature seeds collected from the same branch of the mother tree were selected as the research objects.Concentrations of 0,25,50,and 75 mg·L^(-1) NAA were used to analyze the regulatory effects of NAA on root morphology and endogenous hormone content of Phoebe sheareri seedlings.The results showed that NAA treatment,inhibited taproot elongation,increased taproot diameter and total root surface area,and increased total root biomass significantly(P<0.05).The total root surface area and total root length reached their maximum when the concentration of NAA was 75 mg·L^(-1).The number and total length of primary lateral roots increased and reached the maximum,respectively.Exogenous hormone NAA could significantly increase the content of trans-zeatin(TZ)in root system of the seedlings(P<0.05).The root topological index significantly increased with the increase of NAA concentration(P<0.05),and the root system evolved towards the fishtail branching type.Treatment with 75 mg·L^(-1) NAA significantly increased the root biomass and TZ content(P<0.05)but significantly reduced the root endogenous hormone abscisic acid content(P<0.05).These results indicate that NAA treatment could promote the synthetic accumulation of root TZ and promote the development of root system.