The effect of heat and cold stress (47.5°C and 0°C respectively for 2 min applied to the roots) on per cent moisture content, relative water content, photosynthetic pigments, proline accumulation, levels of sugars and free amino-acids was studied in rice (Oryza saliva L. cv. Guj. 17) seedlings. Shoot and root growth was inhibited by heat and cold treatments. Percent moisture content and relative water content of the treated seedling were altered; it was also noticed that proline accumulation increased in the seedlings where per ceni moisture content was high but it decreased where the seedlings had low per cent moisture content. Sugars showed an effect of osmoregulant at 1 hr. after both the treatments but it changed metabolism as growth period advanced. Free amino-acids, Chlorophyll a/b ratio and levels of carotinoids were also altered.
