Abstract:

In order to investigate effects of Zinc stress on growth of citrus rootstocks, changes relatively physiological indexes and zinc contents in different parts of trifoliate orange, sour orange and red tangerine were determined under 0mg?L-1(zinc deficiency),0.005 mg?L-1(low zinc), 0.05 mg?L-1(optimal zinc) and 0.5 mg?L-1( zinc excess) with hydroponics. The results showed that zinc stress remarkably inhibited the growth of trifoliate orange and sour orange, whereas had little influcence on growth of red tangerine, POD activities in roots of trifoliate orange and sour orange were significantly lower under zinc deficiency and low zinc treatments than under optimal zinc treatment, while CAT activities in roots of red tangerine had no significant difference among Zn treatments; Pro content in leaves and roots of the three citrus rootstocks were notably higher under zinc stress than under optimal zinc treatment, leaf MDA and root Pro content of trifoliate orange were relatively lower than those of sour orange and red tangerine under Zn treatments. Zn contents in roots,stems and leaves of the three citrus rootstocks increased with increasing supply of Zn, Zn contents in roots were higher than other parts on the same Zn treatment, the ratio of leaf/root, stem/root and leaf/stem of zin translocation coefficient under zinc excess were significantly lower than those of other Zn treatments.It’s suggested that there exist differential response in relation to Zn stress among the three citrus rootstocks.