Physiological aspect of drip irrigation: response of tomato plant to partial wetting of root system
1988
Santos, Y.E.A.
Pot experiments were conducted to assess the response of tomato on the distribution and degree of uniformity of water in the root zone. Growth containers were partitioned to facilitate wetting of 100%, 75%, 50% and 25% root system. Using the "pouring method", the crops showed a corresponding decrease in water use efficiency as a result of partial wetting with varying water regime. Roots were observed to concentrate in the wet regions of the containers, losing its radial symmetry. Microscopic examination revealed that roots in wet and dry regions exhibited the same xylem vessel diameter. However, larger xylem region and greater mass of parenchymatous cells were observed in roots collected in the wet region. By an improvised drip irrigation, response of tomato to partial wetting of root system did not vary significantly. Adaptive mechanism to conserve water, like reduced shoot production was not exhibited by the plant. Leaf water potential was maintained even with a decrease in root volume exposed to water supply. It is suspected that the method enhanced aeration of the root zone which favored taller, higher water use efficiency and production of greater number of larger fruits in tomato planted to 50% watered region. Drip method in this study exhibited a controlled method of water application, maintained available water at constantly low tension and consequently, favored the conditions for optimum growth and development of tomatoes.
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