黄腐酸对淹水平邑甜茶根生长与氮代谢的影响

Regulation of Fulvic Acid on Root Architecture and Nitrogen Metabolism of M.hupehensis Seedlings with Flooding

为了探究淹水条件下黄腐酸预处理对平邑甜茶幼苗生长和氮代谢的调控作用。通过根施不同浓度黄腐酸(50 mg·L^(-1)、200 mg·L^(-1)、500 mg·L^(-1)、1000 mg·L^(-1)),研究淹水胁迫下平邑甜茶幼苗根系生长及植株氮代谢相关的指标变化。结果表明,在淹水环境中,平邑甜茶幼苗生长受到抑制,根系和叶片中硝态氮含量、铵态氮含量、游离氨基酸含量、NR活性及GS活性均受到影响。黄腐酸预处理的平邑甜茶幼苗提高了淹水环境下根系和叶片中硝态氮含量、铵态氮含量、游离氨基酸含量以及NR活性和GS活性,综合来看,以黄腐酸浓度500 mg·L^(-1)效果最明显。黄腐酸具有浓度效应,表现为低浓度促进高浓度抑制。说明外源黄腐酸在一定程度上缓解了淹水胁迫对平邑甜茶幼苗的伤害,能调控淹水条件下平邑甜茶幼苗氮代谢途径、促进根系生长,保障淹水幼苗根系正常的生长。

To explore the regulatory effect of fulvic acid pretreatment on the growth and nitrogen metabolism of M.hupehensis seedlings under flooding conditions,changes in different indexes,including root growth,nitrate nitrogen content,ammonium nitrogen content,free amino acid content,as well as NR(nitrate reductase)activity and GS(glutamine synthetase)activity in roots and leaves of M.hupehensis seedlings were investigated by applying fulvic acid at different concentrations(50 mg·L^(-1),200 mg·L^(-1),500 mg·L^(-1),1000 mg·L^(-1)).The results showed that the growth of M.hupehensis seedlings was inhibited,and the nitrate nitrogen content,ammonium nitrogen content,free amino acid content,NR activity and GS activity in roots and leaves were affected.The contents of nitrate nitrogen,ammonium nitrogen,free amino acid,NR activity and GS activity in roots and leaves of M.hupehensis seedlings treated with fulvic acid increased under flooding environment.By contrast,the effect of fulvic acid concentration of 500 mg·L^(-1) was the most obvious.Fulvic acid exhibited a concentration effect,showing that low concentration of fulvic acid promoted root growth and increased nitrate nitrogen content,ammonium nitrogen content,free amino acid content,NR activity and GS activity in roots and leaves of M.hupehensis seedlings,while high concentration of fulvic acid inhibited the changes.The results indicated that exogenous fulvic acid alleviated the damage of flodding stress on M.hupehensis seedlings to a certain extent,regulated the nitrogen metabolism pathway of M.hupehensis seedlings under flooding conditions,promoted root growth,and ensured the normal growth of flooded seedling roots.