Chin J Plant Ecol ›› 2008, Vol. 32 ›› Issue (2): 491-500.DOI: 10.3773/j.issn.1005-264x.2008.02.029

• Research Articles • Previous Articles     Next Articles


CAI Kun-Zheng, WU Xue-Zhu, LUO Shi-Ming*()   

  1. Institute of Tropical and Subtropical Ecology, South China Agricultural University, Guangzhou 510642, China
  • Received:2006-08-17 Accepted:2007-03-15 Online:2008-08-17 Published:2008-03-30
  • Contact: LUO Shi-Ming


Aims Water stress is one of the most important ecological factors affecting yield and quality of rice (Oryza sativa), and osmotic adjustment is the main mechanism for the crop to adjust to drought. Our objective was to elucidate the effects of water stress on osmolytes at different growth stages in leaves and roots of rice.
Methods We used the rice variety Feng-Hua-Zhan grown in pots to study the effects of water stress on inorganic and organic osmolytes in leaves and roots. Water was withheld 15 d at the growth stages of tillering, panicle differentiation, heading and filling.
Important findings Water stress significantly decreased leaf water potential. Organic osmolytes including soluble sugar, proline and free amino acid and inorganic osmolytes including K+ and Mg2+ in leaves and roots increased significantly after drought treatment at different growth stages. These osmolytes could be reduced to normal levels after re-watering at the tillering stage, but not at the panicle differentiation and heading stages. Osmolytes accumulated to higher levels after drought treatment at panicle differentiation and heading stages than at other growth stages, and organic osmolytes accumulated to higher levels than inorganic osmolytes in the different treatments. The order of osmotic adjustment (OA) ability at different growth stages was: heading, panicle differentiation, filling and tillering. The OA in roots was lower than but positively correlated to OA in leaves. Roots were more sensitive and had a more rapid response to water than did leaves. The order of contribution for osmotic adjustment in leaves and roots with different osmolytes was: K+ > Ca 2+ > soluble sugar > Mg 2+ > free amino acid > proline.

Key words: rice, water stress, osmotic adjustment, osmolyte, root system, leaf