Accumulation Of Cadmium And Metal Nutrient Elements And Expressions Of IRT1 Gene Of Edible Amaranth In Iron Deficiency, Zinc Deficiency Or Calcium Deficiency

Eight cultivars of edible amaranth, common vegetable found in Guangzhou, were selected to conduct a hydroponics culture. The concentrations of metal nutrient elements and Cd were measured in Calcium(Ca), iron(Fe), and zinc(Zn) deficiency, respectively, in order to investigate their accumulation in edible amaranth. The expression of IRT1 in root of low-Cd accumulation cultivar Baigenjianye(B) and high-Cd accumulation cultivar Huahong(H) were measured to expound the relation between the uptakes of metals and the expression of IRT1. The detailed results were showed below:(1) In the Ca and Fe deficiency treatments, the biomass of eight amaranth cultivars decreased significantly compared with controls(p<0.05). Especially for B cultivar, the decreased rate of shoot biomass ranged from 79.86% to 85.55%, and the root biomass decreased 63.11% and 68.91%, respectively. In the Zn deficiency treatment, the cultivars with greater biomass grown in a complete nutrient solution had a significant increase in biomass, yet those cultivars with less biomass exhibited an inhibition. In the Zn deficiency treatment, the biomass of B cultivar decreased 35.07%. However, the biomass of Liuye(L) cultivars even increased 31.67%.(2) In the Ca and Fe deficiency treatments, the concentrations of Cd and metal nutrient elements in shoots of the eight cultivars were increased significantly(p<0.05). In the Ca deficiency treatment, the Cd concentrations in shoots and roots were 1.12 ~ 2.70-fold and 1.15~4.12-fold higher than the control, respectively. In the Fe deficiency treatment, the Cd concentration increased by 2.40 to 0.28 times in shoots, and 2.65 to 0.36 times in root. In the Zn deficiency treatment, eight cultivars exhibited different trends in Cd accumulation, and these trends were showed in concentration of Cd in shoot, Zn deficiency could promote accumulation of Cd in low-Cd accumulation cultivar, but inhibited it in high-Cd accumulation cultivars.(3) Ca and Fe deficiency could significantly promote metal nutrient elements accumulation in shoots(p<0.05). In the Zn deficiency treatment, the change trends of concentration of metal nutrient elements were not fully identical. And in four treatment groups, there was a significant and/or very significant positive correlation between Cd and metal nutrient elements in amaranth shoots, yet analogous results hadn't been observed in their roots.(4) In the Fe and Zn deficiency treatment,the expression of IRT1(Fe transporter proteins gene) in the high-Cd and low-Cd accumulation cultivars were significantly increased(p<0.05), and increased 8.53 and 4.28-fold in B and 1.41 and 1.20-fold in H higher than the controls, respectively. There was a significant inhibition effect observed in the expression of IRT1 in roots of the two cultivars under Ca deficiency.