Effect of water stress on proline and relative water content in tomato cultivars

Signiflcant accumulation of stress induced proline was observed in all 8 tomato cultimrs studied at 4 levels of stress, i.e., control (unstressed), 4, 7, 10 days of stress. Significant mrletal differences towards proline accumulation were observed. Based on this, tomato culthars were ranked as very high proline accumulating where increase was as high as 156 fold (over control) upto day 10 of stress, medium proline accumulating cultimrs (i.e., fold increase between 80 and 88) upto day 10 of stress, third group which required longer stress period to accumulate proline. During this investigation, high proline accumulating tomato cultimrs were found to be more susceptible to imposed levels of water stress. Leaf relative water content (RWC) declined with increasing stress duration, the minimum RWC (44.5 per cent) was recorded upto day 10 of stress in some cultimrs. Correlation between proline accumulation and stress magnitude was found to be statistically highly significant. Relemnce of proline changes in relation to drought tolerance is discussed.