赤霉素和细胞分裂素对狗牙根分蘖的影响

Effects of Gibberellin and Cytokinin on Tillering of Cynodon dactylon L.

狗牙根(Cynodon dactylon L.)是应用最广泛的暖季性草坪草种之一,有极高的观赏价值。本研究以‘新农1号’狗牙根(C dactylon(L.)Pers.‘Xinnong No.1’)为试验材料,分别喷施1μmol/L赤霉素(GA_(3))和细胞分裂素(6-BA),分析分蘖节中生理物质的响应规律。结果显示:外源6-BA促进分蘖的生长,而外源GA_(3)可抑制分蘖的发生。3个时期喷施6-BA后分蘖数增加,生理指标(POD、SOD、CAT活性以及渗透调节物质)与CK相比含量升高,MDA含量降低,通过统计发现在三叶期喷施6-BA效果最佳,分蘖数是CK的1.2倍。而五叶期、七叶期喷施GA_(3)后生理指标与CK相比含量降低,从而导致MDA含量升高并抑制分蘖的发生。同时,喷施外源激素对内源激素含量也产生了影响3个时期喷施6-BA分蘖节中玉米素核苷(ZR)含量增加、生长素(IAA)和赤霉素(GA_(3))含量减少,降低了IAA/ZR比值,而五叶期和七叶期喷施GA_(3)提高了分蘖节中IAA、GA_(3)含量,降低了ZR含量,提高了IAA/ZR比值;试验结果表明IAA和ZR在分蘖发生过程中起关键作用,主要通过改变IAA和ZR含量以及调节IAA/ZR的比值影响分蘖数量。研究结果对于认识狗牙根分蘖的基本特征具有借鉴意义,可用于指导培育多分蘖狗牙根新品种。

Cynodon dactylon L.is a preminant warm-season turfgrass species extensively employed for its high ornamental value.In this study,C dactylon(L.)Pers.“Xinnong No.1”was subjected to application of 1μmol/L gibberellin(GA_(3))and cytokinin(6-BA)individually,with the aim of analyzing the physiological responses within tiller nodes.The results showed that the application of exogenous 6-BA simulated tiller growth,whereas exogenous GA_(3) suppressed tillering initiation.The number of tillers exhibited a notable increase,particularly at the three-leaf stage,with a marked 1.2-fold increment.This enhancement accompanied by elevated levels of physiological indicators,including peroxidase(POD),superoxide dismutase(SOD),and catalase(CAT)activities,as well as osmoregulatory substances.Additionally,the malondialdehyde(MDA)content decreased following 6-BA application across the three observed periods,in comparison to the control group(CK).In contrast,the application of GA_(3) at the five and seven leaf stages resulted in reductions in various physiological indexes when compared to the CK group.These reductions led to an increase in MDA content and inhibited the initiation of tillers.Moreover,the exogenous hormone treatments had significant effects on endogenous hormone levels.Specifically,the application of 6-BA across the three periods led to an increase in zeatin nucleoside(ZR)content and a decrease in the levels of indole-3-acetic acid(IAA)and GA_(3) within the tiller nodes.This resulted in a reduction of the IAA/ZR ratio.Conversely,the application of GA_(3) at the five and seven leaf stages increased IAA and GA_(3) content and decreased ZR content within the tiller nodes,consequently increasing the IAA/ZR ratio.In conclusion,both IAA and ZR played a key role in the process of tiller development,impacting the tiller number primarily through modulation of IAA and ZR contents and regulation of the IAA/ZR ratio.The findings from this study offer valuable insights into the fundamental characteristics of C.dactylon L.tillering and can guide the breeding efforts aimed at developing new varieties of multi-tiller C.dactylon L..