Variation in total soluble sugar content due to salinity stress in some native rice cultivars of north Kerala, India

In order to estimate soluble carbohydrate levels in rice leaves under different salinity stress levels, rice genotypes from both saline and non-saline rice tracts of North Kerala, India were exposed to 0, 10, 30, 50, 70, 100 and 200 mM of NaCl progressively starting from the 45th day after germination. The plants were maintained at the corresponding salinity levels during their further growth periods. Leaf samples were collected separately from the plants of each treatment on 90th day of growth and total soluble sugar content was estimated by phenol sulphuric acid method. Salinity caused accumulation of soluble sugar content in all the cultivars. High total soluble sugar concentration in the shoot of these rice cultivars is probably for adjusting osmotic potential and for better water uptake under salinity. These mechanisms help the plants to avoid tissue death and enable to continue their growth and development under saline conditions.