THE EFFECT OF SOME HEAVY METAL COMBINATIONS ON GROWTH AND CHEMICAL COMPOSITION OF SOME ORNAMENTAL SHRUBS COMMON IN EGYPT No1. – HOP BUSH (DODONAEA VISCASA L.)

Abstract

A study was undertaken during 2019/20 and 2020/21 seasons to reveal the impact of lead (Pb), cadmium (Cd), and nickel (Ni) in combinations at various concentrations on the survival, growth, and chemical composition of Dodonaea viscasa L. seedlings after two periods of growth (PG): 6-and 18-months from planting. The interaction effect was also studied. The results indicated that survival % was 100% under the different sole or combined treatments, but the mean values of vegetative and root growth traits were gradually decreased with few exceptions as the concentrations of heavy metals were increased to reach minimum by the T4 combination. Elongating growth period up to 18 months significantly improved growth relative to that measured after 6 months. Hence, combining between planting in either unpolluted or polluted mixture with T1 combination and a growing period of 18 months gave the best growth. The gradual increment in HMs concentrations was accompanied by a gradual decrement in pollution resistance index (PRI) percentages, which were higher than 66% at the highest HMs concentrations indicating its high ability to withstand HMs toxicity. Different responses were observed regarding the chemical composition of the leaves and roots. Accordingly, Dodonaea viscosa L. plant can be used as a good phytoremediator.