EFFECT OF IRRIGATION INTERVALS AND WATER SALINITY ON GROWTH AND CHEMICAL COMPOSITION OF Cryptostegia grandiflora PLANTS | ||
| Journal of Plant Production | ||
| Article 20, Volume 28, Issue 1, January 2003, Pages 451-471 PDF (6.57 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jpp.2003.242162 | ||
| Author | ||
| H. A. Mansour, | ||
| Ornamental Horticulture Department, Faculty of Agriculture, Cairo University | ||
| Abstract | ||
| This study was conducted at the Experimental Nursery 0 f the Ornamental Horticulture Department, Faculty of Agriculture, Cairo University, during the two successive seasons of 2000/2001 and 2001/2002. The aim of the study was to investigate the effect of irrigation intervals and irrigation water salinity on the growth and chemical composition of Cryptostegia grandiflora plants. The plants were irrigated (till 100% of field capacity) every 3,6,9 or 12 days using tap water (control) or water containing a mixture of NaCI and CaCI2 (1:1 w/w) at concentrations of 1500, 3000, 4500,6000 or 7500 ppm. Prolonging the irrigation intervals caused steady reductions in the mean survival percentage and the vegetative growth parameters (plant height, stem diameter, number of leaves/plant, number of branches/plant, as well as the fresh and dry weights of leaves, stems and roots/plant), with the survival percentage being significantly reduced by irrigation at the longest intervals (12 days), while the vegetative growth parameters were significantly reduced by irrigation intervals of 9 or 12 days, compared to irrigation every 3 days. Also, prolonging the irrigation intervals from 3 to 6, 9 or 12 days resulted in steady reductions in the leaf contents of total chlorophylls, Na, CI and Ca, but increased the total carbohydrates and proline contents. Raising the salt concentration in the irrigation water also reduced the survival percentage and vegetative growth characteristics steadily, especially with concentrations of 6000 and 7500 ppm, which gave significantly lower values than the control. In addition, raising the salt concentration caused steady reductions in the total chlorophylls content, but increased the proline, Na, CI and Ca contents in the leaves. The total carbohydrates content was increased by salt concentrations of 1500 or 3000 ppm, whereas higher salt concentrations (4500-7500 ppm) reduced the total carbohydrates content steadily, compared to the control. A significant interaction was detected between the effects of irrigation intervals and salt concentrations. As a result, Cryptostegia grandiflora plants tolerated saline water irrigation at concentrations of up to 7500 ppm, combined with irrigation intervals of up to 6 days, with no significant reduction ins urvival percentage. With lower salt concentrations, the plants c an be irrigated at longer irrigation intervals (up to 12 days, using a salt concentration of 4500 ppm or less) with no Significant reduction in survival percentage. Moreover, the adverse effect of salinity on some growth characteristics (such as plant height and stem diameter) was less pronounced when the plants were irrigated at short intervals (every 3 days), but as the irrigation intervals were prolonged, the plants became more susceptible to salinity. In general, the most vigorous growth was obtained when the plants were irrigated every 3 days using tap water. Prolonging the irrigation intervals andlor raising the salt concentration resulted .in steady reductions in the values recorded for the different vegetative growth characteristics. | ||
| Keywords | ||
| Cryptostegia; irrigation intervals; salinity | ||
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