Abstract:
Total agricultural land of the globe becomes insufficient due to the progressive
nature of primary and secondary salinity. High salt content in the irrigation water
or soil is a serious restriction factor to the cultivation of many crops. Salinity has
significant influence in maintaining the balance nature of osmosis, the availability
of water and nutrients, and the formation of free radicals specially in rice plant
since it’s a staple food in many Asian countries. This study was carried out to
determine the effect of ascorbic acid (vitamin C; 100 mg/l,) and Nicotinamide
(Vitamin B3; 250mg/l) on enhancing of salt tolerance ability of selected rice
varieties (moderately salt tolerance rice varieties; At401, Bw400, Bg400-1, Bg369,
a salt sensitive variety Bg310) at diffrent salinity levels (0 dS/m, 3 dS/m, 5 dS/m,
7 dS/m, 10 dS/m) under greenhouse conditions at temperature 30°C. Two week
old seedlings were transplanted into a simple hydroponic system which had the
particular saline level that was induced by adding sodium chloride. Then ascorbic
acid (100 mg/l) and nicotinamide (250mg/l) were added to the hydroponic solution
separately. After a week of induced salinity, the highest leaf area (18.22 cm2), plant
height (18.59 cm), chlorophyl content (0.33 mg/ g fresh weight) and proline
content (18.46 µg/g fresh weight) were observed in At401 in the presence of
ascorbic acid and nicotinamide at 7dS/m. However, the lowest value for the all
above parameters were observed in Bg 400-1 at the lowest salinity (0 dS/m). In
contrast, the highest sugar content was recorded in Bg400-1 (9.41 mg/g fresh
weight) at 3 dS/m in the absence of both ascorbic acid and nicotinamide, whereas,
At401 had the lowest sugar content (8.71 mg/g FW) at 0 dS/m in the presence of
ascorbic acid. It was observed that both vitamins ascorbic acid and nocotinamide
enhance the performance of At401 rice variety under high salinity compared to all
other varieties of similar type.
