Carbohydrate status in response to ion regulation of two rice varieties (Oryza Sativa L.) grown in saline medium

Abstract

Two experiments were conducted to test varietal salt tolerance differences in the growth of rice and to identify initial ion‐specific salinity effects on ion regulation and carbohydrate metabolism.

The tillering growth stage of sensitive Giza 35 was more depressed due to high NaCl salinization than tolerant Giza 159. At low external K/Na there were no significant varietal differences in ion regulation. Reducing sugars generally were little affected by salinity. Salinization increased the low sucrose level in shoots of Giza 35 considerably, whereas the high sucrose level of Giza 159 was of little change. KC1 was most stimulative; sulfate had little effect in Giza 35 but decreased sucrose in Giza 159. Salinity Increased shoot starch content more in Giza 35 than in Giza 159, KC1 was most effective, whereas there was no change due to sodium sulfate treatment.

Possible interactions of ion regulation and carbohydrate metabolism in response to varietal salt tolerance of the two rice varieties were discussed. It is assumed that differences within the carbohydrate metabolism contribute to metabolic tolerance of rice varieties when grown in saline environment.

Key words:

• Carbohydrates
• ion regulation
• rice
• salinity