The Effects of Phosphorus and Nitrate Status on Root Growth and Expression of Cyclin-dependent Kinases (CDKs) in Rice
LI Hai-Bo WANG Xiao-Bing XIA Ming WU Ping (Plant Molecular Physiology and Functional Genomics Laboratory, College of Life Science, Zhejiang University, Hangzhou 310029 )
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.