Effects of mannitol induced osmotic stress on proline accumulation, pigment degradation, photosynthetic abilities and growth characters in C3 rice and C4 sorghum     

Suriyan Cha-Um  Souvanh Thadavong  Chalermpol Kirdmanee 《Frontiers of Agriculture in China》2009,3(3):266-273

Osmotic stress is one of the most important abiotic factors which inhibit growth and development in both the vegetative and reproductive stages of many plant species. The aim of this investigation was to compare the biochemical and physiological responses in C₃ rice and C₄ sorghum to water deficit. Chlorophyll a (Chl_a), chlorophyll b (Chl_b), total chlorophyll (TC) and total carotenoid (C_x+c) contents in both rice and sorghum seedlings under osmotic stress were adversely affected, related to increasing osmotic pressure in the culture media. In addition, the chlorophyll’s fluorescence parameters and net photosynthetic rate (P _n ) decreased, leading to growth reduction. Also, a positive correlation was found between physiological and biochemical data, while proline accumulation showed a negative relationship. The Chlb, P _n and fresh weight were maintained better in osmotic-stressed (− 1.205 MPa) C₄ sorghum seedlings than those in C₃ rice seedlings. The growth and physiological responses of C₃ rice and C₄ sorghum decreased depending on the plant species, the osmotic pressure in the media and their interactions. Pigment content and P _n ability in C₄ sorghum grown under mannitol-induced osmotic stress increased to a greater degree than in C₃ rice, resulting in maintenance of growth.  相似文献