NACL STRESS IN RICE SEEDLINGS - STARCH MOBILIZATION AND THE INFLUENCE OF GIBBERELLIC ACID ON SEEDLING GROWTH

摘要

The growth of shoots and roots of rice (Oryza sativa L., cv. Taichung Native 1) seedlings was significantly inhibited when the seeds were subjected to NaCl stress. NaCl markedly decreased the mobilization of starch in endosperm. Results also showed that alpha-amylase activities in endosperm were reduced when rice seeds were germinated in the presence of NaCl. NaCl-inhibition of alpha-amylase activities was counteracted by gibberellic acid (GA(3)). GA(3) reduced NaCl-inhibition of shoot growth, but not of root growth. Sugars (sucrose, fructose, and glucose) were able to reduce NaCl-induced growth inhibition of shoots and roots. The possible mechanism by which shoot growth and root growth in NaCl media respond differently to GA(3) is discussed.