Irrigation of Greenhouse Vegetables—Florida （灌溉温室VegetablesFlorida）.pdf

HS786 Irrigation of Greenhouse Vegetables—Florida Greenhouse Vegetable Production Handbook, Vol 31 G. J. Hochmuth2 Vegetables produced in greenhouses require ample A good example of the relationship of fruit quality and amounts of water for optimum growth, yield, and fruit water is blossom-end rot (BER). BER is a Ca deficiency quality. Water is the “universal solvent” in plant cells and is disorder that causes fruit cells to collapse and deteriorate. involved in many biochemical processes. Growth processes BER is related to water status because Ca moves in the will slow, and lower yield and quality will result if the plant water stream within the plant and is not retranslocated is without water even for a very short period. greatly by the phloem system. Therefore, when water supply to the plants is low, an associated deficiency of Ca could oc- Water is taken into the plant through the root system and cur. Water moves rapidly to the leaves of the plant because exits as water vapor through the leaves by a process called transpiration is higher at those locations than in the fruits. transpiration. Along the way, water is involved in the many Therefore, under water stress, proportionately less water processes contributing to growth and yield. As water leaves (and Ca) is transported to the fruits. The objective is to the plant, the evaporation process cools the plant. Only maintain healthy plant roots and uniform levels of water about 2% of the water that enters the plant is consumed in and calcium availability to the plants. biochemical reactions. The majority is transpired. Optimum management of other cultural factors such a