磷和硫对空心菜吸收砷的影响

INFLUENCE OF PHOSPHATE AND SULPHATE ON THE YIELD AND ARSENIC ACCUMULATION OF SWAMP-CABBAGE

本文通过水培空心菜中砷与磷以及砷与硫配比试验,研究PO_4(?)和AsO_4^(?)以及SO_4^(2-)和AsO_4^(3-)共存对空心菜生长及砷累积的影响.结果表明:5ng·l^(?)(以元素计,以下同)PO_4^(3-)或SO_4^(2-)时,AsO_4^(3-)显著降低空心菜产量,PO_4^(3-)和SO_4^(2-)含量提高到3O—100mg·l^(?)时,空心菜产量明显提高.前者因空心菜在低磷或低硫条件下累积高量砷中毒所致,后者则与磷和硫强烈抑制空心菜积累积砷.解除其砷毒胁迫有关.在30mg·l^(-1)PO_4^(3-)和SO_4^(2-)时,0.2mg As·l^(?)促进空心菜生长,但在100mg·l^(-1)PO_4^(3-)和SO_4^(2-)时.没发现这种现象,表明微电机量砷有利于空心菜生长.而过量磷和硫阻抑砷有益作用的发挥.

Swamp-cabbage were planted in Hoagland's solutions containing different concentrations of arsenate, sulphate and phosphate, and the effects of phosphate and sulpate on their yields and arsenic accumulation at different arsenate levels were evaluated. Significant and without significant adverse effects were found at 0. 2-5mg · 1-1 As on swamp-cabbage yield with 5mg · 1-1 P and S and 30-100mg · 1-1 P and S,respectively. The former was due to high arsenic accumulation by roots at low soluble P and S levels. The latter was caused by strong inhibition of higher levels of soluble P and S on arsenic accumulation in plant, increasing plant tolerance to arsenate toxicity.It was found that 0. 2mg · 1-1 As increased swamp-cabbage yield at 30mg ·1-1 solution P and S,slightly increased at l00mg · 1-1 soluble P and S. These results showed that trace arsenic might be helpful to swamp-cabbage growth, and excess P and S inhibited positive function of arsenic in swamp-cabbage.