根际CO_(2)对薄皮甜瓜根系生长及内源激素的影响

Effects of Root-zone CO_(2) on Root Growth and Endogenous Hormones of Melon

以薄皮甜瓜‘玉美人’为试材,采用气雾法根际CO_(2)自动控制系统,研究了6种不同的根际CO_(2)浓度(0.2%、0.4%、0.6%、0.8%、1.0%和1.2%,其中以0.2%的常规根际CO_(2)浓度为对照)下薄皮甜瓜根系生长指标和根系内生长素(IAA)、细胞分裂素(CTK)、赤霉素(GA)和脱落酸(ABA)含量的变化,以期为深入研究根际高CO_(2)下植株生长的内在机制提供参考依据。结果表明:随着CO_(2)浓度升高和处理时间的延长,薄皮甜瓜根系生长指标和促进生长型激素(IAA、CTK和GA)的含量均表现先增加后下降的变化趋势。CO_(2)处理前6 d,根长、根系表面积、总根尖数、根系平均直径、根系活力、IAA、CTK和GA的含量均显著高于对照,且浓度越高,增加的幅度越大。处理9 d后,根系生长受到不同程度的抑制,IAA、CTK和GA含量随CO_(2)浓度的升高而下降,而ABA含量逐渐增加。根际CO_(2)浓度不同,激素达到峰值的时间不同,CO_(2)浓度越高,激素含量达到峰值的时间越早。综上可知,短期(<6 d)根际CO_(2)富集促进薄皮甜瓜幼苗根系的生长和促生长型激素(IAA、CTK和GA)的合成。随富集时间的延长,IAA、CTK和GA含量下降,根系生长受到抑制。

Taking melon ‘Yumeiren’ as the test material, and the aeroponics culture CO_(2) automatic system, the changes of root growth indexes and auxin(IAA),cytokinin(CTK),gibberellin(GA) and abscisic acid(ABA) content in the roots of melon under six different rhizosphere CO_(2) concentrations(0.2%,0.4%,0.6%,0.8%,1.0% and 1.2%,0.2% of the conventional root-zone CO_(2) concentration were used as the control) were studied, in order to provide reference for in-depth study of the internal mechanism of plant growth under root-zone high CO_(2) concentration.The results showed that with the increase of CO_(2) concentration and the prolongation of treatment time, the growth indexes and the content of growth-promoting hormones(IAA,CTK and GA) of melon showed a trend of first increasing and then decreasing.Before 6 days of CO_(2) treatment, the root length, root surface area, total number of root tips, mean diameter of root, root activity, IAA,CTK and GA content were significantly higher than the control, and the higher the concentration, the more the increase.After 9 days of treatment, root growth was inhibited to varying degrees.The content of IAA,CTK and GA decreased with the increase of CO_(2) concentration, while the content of ABA gradually increased.The concentration of root-zone CO_(2) was different, and the time for the hormone to reach the peak was different.The higher the concentration of CO_(2),the earlier the time for the hormone content to reach the peak.In conclusion, the high root-zone CO_(2) concentration of melon could promote the growth and the synthesis of growth-promoting hormones(IAA,CTK and GA) of melon seedling roots in a short period of time(<6 days).With the extension of the enrichment time, the content of IAA,CTK and GA decreased, and the growth of root was inhibited.