Interaction effect of nickel and cobalt in irrigation water on growth, chemical constituents and mineral content of Cypress (Cupressus Sempervirens, L) seedling grown on sandy soil

Abstract

A pot experiment was conducted in two seasons (2013 and 2014) to evaluate the combination effect of nickel and cobalt at 0, 10, 20, 40 and 80ppm of both elements  in irrigation water on growth, chemical constituents and mineral content of Cypress (Cupressus Sempervirens, L) seedling grown on sandy soil.

Results showed that all tested treatments of Ni and Co combinations caused significant increases in stem length and stem diameter of Cypress seedling as compared with control treatment with the exception of 80 ppm Ni + 80ppm Co combination treatment for stem length and 40ppm Ni + 80 ppm Co and 80ppm Ni combined with 40 or 80ppm Co for stem diameter. The fresh and dry weight of root, stem and leaves were significantly increased by combined 10 and 20 ppm of Ni and Co, while the highest concentration of both heavy metals combinations  (40 and 80 ppm) led to significant decreases in fresh and dry weight of seedling organs in most cases. The obtained results revealed that chlorophyll (a, b), carotenoids and sugars increased with Ni or Co at 10, 20 and 40 ppm concentration as compared with control treatment. However the highest rate of either Ni or Co (80 ppm) reduced carotenoids, soluble, non- soluble and total sugars content less than control. Total indoles and shoot crude fiber content of Cypress seedling were increased with all Ni or Co treatments. Ni and Co treatments led to increases in leaf N, P, K, Ni and Co content of cypress seedling plant as compared with control treatment. Moreover, leaf N, P and K content were showed progress increasing with increasing level of both Ni and Co from 10 to 40 ppm.