Tipburn of cabbage has been prevented in growth-chamber studies by enclosing plants at night in plastic bags to encourage root pressure flow. Short-period (4 hour) uptake studies of 45Ca from nutrient solutions have shown a large accumulation of 45Ca in the inner leaves when the entire plant was enclosed, so that root pressure flow occurred. However, there was essentially no accumulation of 45Ca in the inner leaves when only the inner leaves were enclosed and the outer leaves were exposed to an atmosphere that encouraged transpiration from these leaves. The small amount of 45Ca present in these leaves accumulated in the center one-half of the leaves and none was found in the marginal areas of the leaves. A tipburn of developing leaves of young ‘Red Core Chantenay’ carrot plants also has been prevented by enclosing the plants in plastic bags at night to encourage root-pressure flow. This disorder of carrot leaves occurs with rapid growth in controlled-environment chambers. Daily sprays of CaCl2 solutions greatly reduced the severity of this injury. Papers in this symposium have documented the deficiency of Ca in low-transpiring tissues. It has been suggested that tissues with low-transpiration obtain the required amount of Ca with the water required to satisfy metabolic or osmotic requirements(1). Also, it has been demonstrated that Ca is accumulated in low-transpiring tissues of cabbage through daily fluctuations in water content of the plants(2,5). Ca was found to move into the tissues each night as the plant increased in water content and. © 1979, Taylor & Francis Group, LLC. All rights reserved.
