ISSN 2167-0447
International Journal of Agricultural Sciences ISSN: 2167-0447 Vol. 3 (4), pp. 483-492, May, 2013. © International Scholars Journals
Full Length Research Paper
Effect of salinity and silicon application on photosynthetic characteristics of sorghum (Sorghum bicolor L.)
Jafar Nabati1, Mohammad Kafi2, Ali Masoumi3 and Mohammad Zare Mehrjerdi 2
1Ph.D. in crop physiology, Yakta Seed Technologists Company
2Faculty of Agriculture, Ferdowsi University of Mashhad
3Faculty of Agriculture, Payam Noor University
*Corresponding author. E-mail: [email protected]
Accepted 10 April, 2013
Abstract
Supplementing Si to the soil is one of the alternative strategies for overcoming the negative effects of salinity on crop yield. Therefore, a field experiment was conducted to investigate the effects of silicon application on photosynthesis characteristics of two sorghum (Sorghum bicolor L.) cultivars (CV) (Omidbakhsh and Sepideh) under three levels of salt stress (5.2, 10.5 and 23.1 dS m-1), two levels of Si (1.44 and 1.92 g.kg-1soil) application and control (0 g.kg-1 soil) arranged as a split, split plot design. Salinity significantly decreased photosynthesis rate, chlorophyll a (Cha), chlorophyll b (Chb), and dry matter accumulation (DM) of the sorghum plants, indicating that plants suffered from stress. In addition, salinity imposed a remarkable decrease on variable fluorescence (Fv) and quantum yield. At highest level of salinity supply of 1.92 g.kg-1soil Si, alleviated negative effects of salinity and increased photosynthetic rate (24%), transpiration rate (19%), quantum yield (38%), total pigments (22%) and dry matter accumulation (65%) compare with 1.44 g.kg-1soil Si application. Correlation between shoot dry weight, Cha and Chb were no significant. In the relative salt sensitive CV (Sepideh) leaf Cha, Chb content and Cha/Chb, was higher than salt tolerance CV (Omidbakhsh), however, Omidbakhsh showed higher photosynthetic rate and dry matter accumulation.
Key words: Salinity stress, photosynthesis, chlorophyll fluorescence, transpiration rate.