Tissue accumulation and subcellular distribution of vanadium in Brassica juncea and Brassica chinensis

Brassica juncea and Brassica chinensis were subjected to varying doses of V for 40 days to investigate the effects on uptake, tissue accumulation and subcellular distribution of V in two cultivars by differential centrifugation. Subcellular distribution level of V in plant organs was in sequence as follows: root > leaf > stem. There was a significant difference of V accumulation and distribution in roots and shoots between the two vegetables: V content in B. juncea was more than that in B. chinensis. Plant fractionation indicated that 73.4%-78.6% of V in roots, 74.9%-79.8% in stems, and 86.6%-93.2% in leaves were accumulated in cell walls and soluble fractions. V accumulation in roots and leaves increased in cell wall but decreased in soluble fractions with V level increasing. V accumulation in stems increased in soluble fractions but decreased in cell nucleus, mitochondria and chloroplasts. At all doses of V stress, B. juncea had higher tolerance to V than B. chinensis did. It suggests that there is a joint contribution of cell walls and vacuoles in V accumulation and detoxification of B. juncea and B. chinensis.