氮素形态对平邑甜茶细胞分裂素水平和叶片生长的影响

Effects of Rhizosphere Nitrate and Ammonium on the Level of Cytokinins and Leaf Growth of Malus hupenensis Rehd

以平邑甜茶(Malus hupenensis Rehd.)实生苗为试材,在水培条件下研究NO3-和NH4+对植株不同器官细胞分裂素水平及对叶片生长的影响。结果表明:NO3-处理0.5h后,根和叶片玉米素及其核苷(Z+ZR)含量迅速升高,并且始终高于NH4+处理和对照。茎部玉米素及其核苷含量在NO3-处理1h后迅速升高,但之后与NH4+处理及对照差异不显著。就异戊烯基腺嘌呤及其核苷(iP+iPA)而言,总体上看根中以NO3-处理较高,茎中各处理差异不大,叶片中则以NH4+处理较高。NO3-处理与NH4+处理相比,更能促进叶片生长,这可能与叶片中较高的玉米素及其核苷含量和较低的ABA含量有关。

Experiments were carried out to study the effects of rhizosphere nitrate and ammonium on the level of cytokinins in different organs and the leaf growth of Malus hupenensis Rehd. seedlings under water culture condition. Results indicated that the concentration of zeatin and zeatin riboside （ Z ＋ ZR） both in roots and in leaves increased quickly in 0. 5 hour after nitrate supply, and the levels of Z ＋ ZR were always higher than ammonium treatment and the control within 24 hours. In stems, the concentration of Z ＋ ZR increased significantly in 1 hour after nitrate treatment, but there was no significant difference between the treatment and the control. The concentration of isopentenyladenine and isopentenyladenosine （ iP ＋ iPA） was higher in roots in nitrate treatment and in leaves in ammonium treatment. No significant difference was noticed in stems between the treatment and the control. The leaf growth in nitrate treatment was better than ammonium treatment, suggesting that it may be involved in higher Z ＋ ZR level and lower ABA level.