Endogenous proline accumulation for osmoregulation in drought-stressed rice genotypes
2010
Capistrano, A.O.V., Philippine Rice Research Inst., Maligaya, Science City of Muñoz, Nueva Ecija (Philippines). Agronomy, Soils, Plant Physiology Div. | Sta. Cruz, P.C., Philippines Univ. Los Baños, College, Laguna (Philippines). Crop Science Cluster
The study determined the effect of drought during early vegetative, panicle initiation (PI) and heading stage on the yield of PSB Rc14 (rainfed) and PSB Rc82 (lowland). The effect of endogenous proline accumulation, as an osmoregulant to drought stress, on yield was also evaluated. Screenhouse experiments were conducted in May-November 2009 at the Philippine Rice Research Institute Central Experiment Station in Muñoz, Nueva Ecija. Drought impositions were carried out for 10 d starting at field capacity one each of the targeted critical stages of crop development. Two sets of experiments were established; one for endogenous proline content analysis that required destructive sampling and another for yield evaluation. The yield of the two test varieties decreased when a 10 d drought occurred at any of the critical crop stages, but were more pronounced during PI and heading stages. It was observed that endogenous proline drastically accumulated when drought-stress occurs at PI and heading stages, indicating the plants' necessity to osmoregulate and counteract water deficit stress at this critical stage of reproductive development. Furthermore, proline levels of Rc14 under flooded condition were comparable witha drought-affected Rc82, indicating that more proline is produced inherently by Rc14 even in on-drought conditions. This observed difference in proline accumulation between the test varieties may be the reason for Rc14's adaptability to rainfed conditions and Rc82's susceptibility to drought. These results provide an opportunity to resolve yield gaps in temporary drought-affected rice environments through proline manipulation.
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