UV-B辐照对设施油桃生长及IAA代谢的影响

Effects of UV-B irradiation on growth and IAA metabolism of greenhouse nectarine(Prunus persica var.nectarina)

为探究UV-B对树体的矮化作用、IAA的恢复效果及原因,以温室栽培的两年生油桃‘鲁油3号’为试材,设置UV-B辐照、UV-B+IAA和UV-B+TIBA (为生长素运输抑制剂)处理,测定了生长及IAA代谢相关指标。结果表明:UV-B处理显著矮化了干高,缩短了枝条节间长度,减少了叶片数,降低了树体的IAA合成前体色氨酸(TRP)含量和IAA含量,提高了抗性、IAA降解酶吲哚乙酸氧化酶(IAAO)的活性。添加IAA后,各生长参数、IAA和TRP含量均得到显著提升,达到甚至高于CK水平,保持了之前的高抗性,并将2种合成关键酶活性提至CK水平,将IAAO的氧化分解活性降至CK水平。TIBA处理显著恢复了茎粗和叶片数,使IAA含量继续显著下降。各处理均未显著影响节间数。可见, UV-B可以通过降低TRP含量、提高IAAO活性来降低IAA含量,起到矮化树体、短缩枝条等作用;外源IAA不仅能很好地抵消UV-B的抑制影响,还能起到促进生长、保持较高抗性的作用。此结果可为设施中壮苗培育以及高UV-B地区树体调控提供参考和理论依据。

In order to investigate the dwarfing effect of UV-B on trees,the recovery effect of IAA and the causes,the two years old‘Luyou 3’nectarine(Prunus persica var.nectarina)cultivated in greenhouse was used as material,and UV-B irradiation,UV-B+IAA and UV-B+TIBA(auxin transport inhibitor)were set up,the indexes related to growth and IAA metabolism were measured.The results showed that UV-B treatment significantly dwarfed the dry height,shortened the internode length of branches,reduced the number of leaves,decreased the content of tryptophan(TRP)and IAA in trees,and improved the resistance and IAAO activity.After the addition of IAA,the growth parameters,contents of IAA and TRP were significantly increased,reaching or even higher than the CK level,maintaining the previous high resistance,and the activities of two key synthetic enzymes were raised to the CK level,and the oxidative decomposition activity of IAAO was reduced to the CK level.TIBA treatment significantly restored stem diameter and leaf number,and continued to significantly decrease IAA content.None of the treatments significantly affected on the number of internodes.It can be seen that UV-B can reduce IAA content by decreasing TRP content and increasing IAAO activity,so as to dwarf the tree and shorten the branches.Exogenous IAA could not only offset the inhibitory effect of UV-B,but also play a role in promoting growth and maintaining high resistance.The results can provide reference and theoretical basis for the cultivation of strong seedlings in facilities and the regulation of tree growth in high UV-B areas.