Abstract: A pot experiment with controlled water supply was conducted to study the effects of different drought stress degree (80% FC, 60% FC, 40% FC, and 20% FC) and nitrogen fertilization rate (0 g·pot-1, 1.2 g·pot-1, 3.6 g·pot-1, and 6.0 g·pot-1） on the accumulation of osmolytes in different organs of Jatropha curcas seedlings. Under drought stress, the soluble protein and free proline in seedling shoots and roots and the soluble sugar in seedling shoots had a great accumulation, and the free proline content in seedling leaves had a great increase with increasing drought stress degree. Also under drought stress, the Na+, Ca2+, and Mg2+ all highly accumulated in seedling various organs, while K+ only accumulated greatly in shoots but slightly in leaves and roots. The effects of nitrogen fertilization on the accumulation of osmolytes in seedlings  depended on drought stress degree and nitrogen fertilization rate. At 80% FC and 60% FC, increasing nitrogen fertilization rate could markedly promote the accumulation of osmolytes in the organs of J. curcas seedlings; at 40% FC, applying 6.0 g·pot-1 weakened the promotion effect on the osmolytes accumulation; whereas at 20%, applying 1.2 g·pot-1 made the plants have a higher capability in osmoregulation, but applying 3.6 g·pot-1 and 6.0 g·pot-1 had less promotion effect, and even, inhibited osmolytes accumulation.

Key words: drought stress, nitrogen fertilization, Jatropha curcas, osmolyte