The absorption of Cr and fluctution of nutrients in mulberry seedlings treated by Cr³⁺and Cr⁶⁺

Abstract

The contents of Cr³⁺and Cr⁶⁺nutritional elements in the various organs of mulberry seedlings cultured hydroponically in the presence of Cr³⁺and Cr⁶⁺were measured. The contents of Cr³⁺and Cr⁶⁺in all organs of mulberry rapidly increased in the case of high concentration of Cr³⁺and Cr⁶⁺added to the culture medium. It was found that the Cr content rate in root was the highest compared with other mulberry organs and above 90% of Cr absorbed by mulberry was stored in root. Moreover, the Cr content rate in root by adding Cr³⁺was higher than that by adding Cr⁶⁺, whereas those in stem and leaf were completely contrary. The movement rate from root to other organs above the ground (stem and leaf) was less proportional to the concentrations of Cr³⁺ and Cr⁶⁺, respectively. However, the correlationship between the content of Cr in mulberry individual and the concentration of Cr⁶⁺ was not obvious, though the proportional correlationship of that for adding Cr³⁺ was very clear. Most of the content rates of plant nutrients in mulberry organs, such as that of K, Ca, Mg, Fe, Mn, Zn, Cu, decreased in the case of addition of Cr. In the contrary Ca content in root, increased when Cr was added in the culture medium.