外源激素对杉木苗木生长及侧枝发育的影响

Effects of exogenous hormones spraying on growth and lateral branch development of Chinese fir

为探讨植物激素对杉木生长和侧枝发育的影响机理,以1年生“洋061”杉木无性系苗木为研究对象,选择独角金内酯类似物(GR24)、外源细胞分裂素[6-苄氨基嘌呤(6-BA)]和外源生长素[吲哚乙酸(IAA)]3种激素,设计不同激素不同浓度的喷施处理,定期测定不同处理的杉木苗高、地径、侧枝长度、侧枝基径及侧枝生长素[吲哚乙酸(IAA)]、细胞分裂素(CTK)含量,探究外源激素对杉木生长及侧枝发育的影响。结果表明:外源激素处理对杉木生长和侧枝发育有显著影响,存在较大差异。IAA处理增强了杉木的顶端优势,抑制其侧枝伸长,促进杉木径向生长;较低浓度的6-BA处理对杉木生长有正向调控作用;GR24处理对杉木侧枝生长有一定抑制作用,但明显增强了杉木的顶端优势,引起杉木侧枝内源激素的变化,一定程度上降低了杉木侧枝的CTK/IAA值,表明GR24可能通过调控CTK与IAA含量来调控杉木侧枝生长。

To explore the mechanism by which plant hormones influence the growth and lateral branch development of Chinese fir,three hormones,strigolactone analogue(GR24),exogenous cytokinin[6-benzylaminopurine(6-BA)],and exogenous auxin[indoleacetic acid(IAA)],were selected to be sprayed on fir at different concentrations.Height,ground diameter,lateral branch length,lateral branch basal diameter,and lateral stem auxin levels were measured regularly to determine the effects of different treatments.The cytokinin(CTK)content was also used to explore the effects of exogenous hormones on the growth and lateral branch development of Chinese fir.The results showed that exogenous hormone treatment had an effect on growth and lateral branch development,and there were significant differences in the effects of different exogenous hormones on the developmental characteristics of the lateral branches.IAA treatment enhanced the apical advantage,inhibited lateral branch elongation,and promoted radial growth.Treatment with lower concentrations of 6-BA had a positive regulatory effect on the growth of Chinese fir.GR24 treatment had an inhibitory effect on the growth of lateral branches but significantly enhanced the apical dominance of fir branches,caused endogenous hormonal changes in lateral branches,and reduced the CTK/IAA ratio of lateral branches.These results indicated that GR24 may regulate the growth of the lateral branches of Chinese fir by regulating the content of both CTK and IAA.