Study On The Main Influence Factors Of Non-heading Chinese Cabbage Tillering

Branching plays a major role in plant structure and yield.Axillary bud formation controlled only by genotype,while the complex network of hormones,genetics and environment regulate the growth of axillary bud.We observed dynamical changes of axillary bud in three varieties of non-heading Chinese cabbage with different tillering trait.The influence of sowing date on tillering of three varieties was investigated.The exogenous hormones and genes that cause different tillering trait of three varieties were investigated.At the same time,we explored the mechanism that new hormone-strigolactones(SLs)affected tillering of non-heading Chinese cabbage.Provide basis for the complex network of hormones,genetics and environment regulating tillering of non-heading Chinese cabbage.The main results are as follows:1.'Su zhou qing' hadn't visible axillary bud at vegetative period.At 10 leaf period,'Ma er tou' had visible axillary bud at each leaf aixl.'Ru gao mao cai' had visible axillary bud amost at each leaf axil at 8 leaf period.'Ma er tou' and 'Ru gao mao cai' almost simultantly had visble axillary bud,while the axillary bud of 'Ma er tou' enlongated earlier and tillering growth rate in 'Ma er tou'(autumn sowing)was stronger before squaring stage.At the same time,the tillering ability was positively correlated with leaf growth rate.The leaf growth rate slowed down with the delay of sowing date,while the tillering related traits didn't changed.With the delay of sowing date,the tillering ability of 'Ma er tou' and 'Ru gao mao cai' weakened,while the influence of sowing date on 'Ma er tou' was stronger.2.'Su zhou qing' did't tillered at vegetative period,and 'Ma er tou' tillered stronger than 'Ru gao mao cai' at whole growing period.IAA(auxin)inhibited tillering of 'Su zhou qing' throuth apical dominance indirectly.CTK(cytokinin)promoted tillering directly,while ZR(zeatin riboside)played a major role in 'Ma er tou' and Z(zeatin)played a major role in 'Ru gao mao cai'.To a certain extent,ABA inhibited tillering of 'Ma er tou' and 'Ru gao mao cai'.At the same time,high(Z+ZR)/IAA and(Z+ZR)/ABA value promoted tillering under centain conditions.MOC1 played a major role on axillary bud formation.MAX2 and BRC1 inhibited tillering of 'Ma er tou' and 'Ru gao mao cai' through regulating the response signal genes of SLs.LOG1 promoted tillering of 'Ma er tou' and 'Ru gao mao cai' by promoting the synthesis of CTK.3.Exogenous GR24 inhibited axillary bud of non-heading Chinese cabbage releasing from dormancy and the effect of higher concentration of GR24 was stronger.While lower concentration of GR24 inhibitted axillary bud elongation more than higher concentration.After GR24 application,the content of Z+ZR and IAA were lower than control.While lower concentration of GR24 effected fasterly.Compared with control,the relative expression of strigolactones perception gene MAX2 and BRC1 increased after GR24 appliction.In addition,the relative expression of MAX2 changed earlier than BRC1.After GR24 application,the relative expression of cytokinins related gene LOG1 was lower than that of control.The relative expression of SPS(regulating the formation and growth of axillary meristem negatively)and SPL9(inhibiting the formation of new leaf)increased after GR24 application.Exogenous GR24 inhibitted axillary bud releasing from dormancy and axillary bud elongation of non-heading Chinese cabbage directly.At the same time,exogenous GR24 could inhibit axillary bud releasing from dormancy and axillary bud elongation indirectly by regulating the hormones signals and expression of tillering related genes.