A comparison of winter-sown tomato plants grown with restricted and unlimited water supply

Abstract

SummaryThe morphology, anatomy and physiology of winter-sown tomato plants grown with a restricted water supply (producing ‘hard’ plants) were compared with those of plants given an unlimited water supply (‘soft’ plants). The stressed plants had smaller and fewer leaves on thinner stems; the reduction in leaf area was largely due to smaller cell size. The leaves and stems also had a higher percentage dry matter; in the stems this was associated with many more and larger starch grains. It is suggested that the improvement in earliness and in fruit quality found in stressed plants originates from this increase in stored carbohydrate.Rates of photosynthesis per unit leaf area were the same in both groups of plants when measured under laboratory conditions. The leaf cell sap had the same osmotic potential but there was a greater proportion of apoplastic water in the leaves of the stressed plants. Transpiration rates in the glasshouse were lower in the stressed plants. Possibilities for the control of plant wa...