Effect of Exogenous Spermidine on the Root Vigor and the Content of Photosynthetic Pigment in the Leaf of Rice Cultivar under Salt Stress
WU Zheng-dong et al(School of Biochemical and Environmental Engineering,Nanjing Xiaozhuang College,Nanjing,Jiangsu 211171)
[Objective]The research on the effect of exogenous spermidine(Spd) on the root vigor and the content of photosynthetic pigment in the leaf of two rice cultivars(Pokkali with salt-tolerant and Peta with salt-sensitive) were studied.[Method] Two rice varieties-Pokkali with the resistance to salt and Peta with the sensitivity to salt were introduced from IRRI and the effect of exogenous Spd on the root vigor and the content of photosynthetic pigment in the leaf of them was analyzed.[Results] The results showed that the root vigor of rice seedlings under salt stress of 200 mmol/L NaCl was increased at first and then decreased with the treatment time-lasting,which descending range of Peta was greater than that of Pokkali;and under the treatment of exogenous Spd,the resistance of Pokkali to salt stress was obviously stronger than that of Peta,which advantage was significant.The content of both Chl and Car in the Pokkali was more than those of CK and the increment range of Chl was larger than that of Car so that the ratio of Car/Chl was significantly decreased.In the variety-Peta,the content of Car was raised and the content of Chl was decreased compared with CK.The treatment of exogenous Spd could improve the content of Chl and Car,the ratio of Chla/Ch1b of two varieties,which were under salt stress,and there was larger increment in the content of Chl in Pokkali compared with Peta.[Conclusion] The treatment of exogenous Spd had the remission effect on the salt stress to root for less damage of salt to root,to the destroy of chloroplast structure for higher content of photosynthetic pigment and reduced the damage of salt stress to the compound of photosynthetic pigment peotien for higher photosynthetic capacity.