不同氮、磷状况对水稻根生长及细胞周期蛋白激酶(CDKs)基因表达的影响

用蛭石与石英砂作为混合固体培养介质研究了低磷 (PO4 3 -)胁迫和部分根系供氮 (NO-3 )对水稻 (O ryzasativaL .)苗期根系生长的影响。结果表明 :低磷胁迫和供氮均能诱导水稻不定根和不定根上侧根的伸长。细胞分裂的进程受依赖细胞周期蛋白的蛋白激酶(CDKs)的调控 ,在缺磷和供氮条件下 ,细胞周期蛋白激酶cdc2Os 1在根系表达都增强 ,而cdc2Os 2的表达无明显变化。cdc2Os 1的这种表达模式与这两种处理下根系的加速伸长具一致性 ,表明在磷缺乏和供氮处理下 ,cdc2Os 1基因在根系表达的增强 ,可能促进了根细胞的分裂活性 ,从而加速不定根和侧根的伸长

The Effects of Phosphorus and Nitrate Status on Root Growth and Expression of Cyclin-dependent Kinases (CDKs) in Rice

The effects of phosphorus (P) deficiency stress and localized nitrate (NO - 3) supply on rice (Oryza sativa L.) root growth in a solid growth medium composed of vermiculite and sand were examined. The results showed that P starvation and localized NO - 3 supply all induced elongation of nodal and lateral roots and subsequently an increase in total root surface area (Tables 1, 2). The procedure of cell division was regulated by cyclin-dependent kinases (CDKs). Northern blot analysis showed that the expression of a rice cyclin-dependent kinases gene, cdc2Os-1, was enhanced by P starvation and nitrate supply in root (Figs.1, 2), while that of another cyclin-dependent kinases gene, cdc2Os-2, showed no difference in these two treatments (Figs. 1, 2). The expression of cdc2Os-1 agree with the performance of nodal and lateral root growth under P starvation and nitrate supply treatments. It suggested that the increased expression of cdc2Os-1 gene induced by P starvation and localized NO - 3 supply maybe involved in the growth of nodal root and lateral root through regulation the cell division activity.