Effect of Foliar Applied Tryptophan on Tuberose Plants for Decreasing the Harmful Effect of Some Heavy Metals Pollution in the Irrigation Water (A) Effect of Cadmium Treatments

Abstract

The present study was carried-out at Antoniadis Research Branch, Horticultural Research Institute, AgricultureResearch Center (ARC), Alexandria, Egypt during two successive seasons of 2018 and 2019. The aim of this study was toevaluate the effects of irrigation water contaminated with cadmium on the growth of Polianthes tuberosa plants and thepossibility of using tryptophan spray treatments to overcome the effects of cadmium pollution. Corms of Polianthestuberosa were planted individually in plastic pots (20 cm diameter) filled with 5 kg of sandy soil. The Cadmiumcontaminated irrigation water treatments were 0,100, 200 and 300 mg/L were applied. The plants were also monthlysprayed by tryptophan at concentrations of 0, 250 and 500 mg/L.The results showed that for vegetative growth parameters there was no significant difference in the interactionbetween cadmium polluted water of irrigation and foliar spray by tryptophan, while a significant reduction was observedin all parameters after irrigation with cadmium polluted water and a significant increase in vegetative growth parameterswas observed after 500 mg/L tryptophan application. For chlorophyll and carbohydrate content, the highest significantvalue was obtained in plants irrigated with tap water and sprayed with 250 mg/L tryptophan while the highest significantlevel of cadmium content in leaves and corms was obtained due treatment by 300 mg/L cadmium without application oftryptophan.