Effect of irrigation water salinity and gibberellic acid treatments on vegetative growth and chemical composition of Conocarpus erectus plants
2011
El-Ziat, R.A.M.
This study was carried out in the Experimental Nursery of the Ornamental Horticulture Department, Faculty of Agriculture, Cairo University, during the two successive seasons of 2008 and 2009. The aim of this study was to investigate the response of Conocarpus erectus plants, grown in a sandy soil, to irrigation water salinity and GA3 treatments on growth and chemical composition of plant. The plants were irrigated three times per week using a mixture of NaCI and CaCl2 (1:1 w/w) at concentrations of 1500,2500,3500 and 4500 ppm. Control plants were irrigated with tap water (270 ppm). The plants were sprayed monthly with GA3 at concentrations of 25, 50, 75 and 100 ppm. Results showed that raising the salt concentration in the irrigation water resulted in steady reduction in all of the vegetative growth parameters, as well as content of chlorophylls a and b, total chlorophylls (a+b), total carbohydrates, P and K %. Raising the salt concentration in the irrigation water increased the content of Na, Ca, and CI and proline %. Spraying plants with GA3 at 50 ppm increased all vegetative growth parameters compared to the other GA3 concentrations (including the control). It can be concluded that Conocarpus erectus plants can tolerate salinity levels up to 4500 ppm in the irrigation water, with significant reductions in vegetative growth. The unfavorable effects of salinity on plant growth can be partly overcome by spraying the plants with GA3 at 50 ppm.
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