Effects Of Calcium Carbonate And Bicarbonate On Zinc Uptake And Utilization Of Wheat Plants

Zinc is essential for normal growth of animal and plant, but soil zinc deficiency can influence the yield and quality of crop and animal, and also human's health. The crops growing on calcareous soil easily suffer from zinc deficiency, while calcium carbonate (CaCO₃) affects zinc uptake greatly. On calcareous soil, there is equilibrium between CaCO₃ and bicarbonate (HCO₃-). Wheat is the most important crop in north of China, and it is mainly grown on calcareous soil. Recently someone report that HCO₃- is propobly the most important reason that affect zinc nutrient. In this dissertation, we added CaCO₃ to water solution to simulate chemical conditions of calcareous soil, so as to clarify the extent of influence to the crop when zinc and CaCO₃ exist together, especially the effect of CaCO₃ on uptake zinc of wheat seedling and HCO₃- concentration and pH. It is important that the relationship of calcareous soil and zinc nutrition can be clarified and also increases the yield and quality of crop. We used water culture method and obtained the main results, which are as follows:(1) In order to study the effects of rates of calcium carbonate (CaCO₃) and zinc (Zn) supplied in the nutrient solutions on growth and zinc uptake of winter wheat plants of five genotypes, as well as bicarbonate concentration and pH value in nutrient solution, the winter wheat seedlings of five genotypes, namely, S02-8, Yuanfeng 998, Zhongyu 6, Xiaoyan 22, and Xiza 1, were mix-cultivated in Hoagland nutrient solution in a greenhouse, and micronutrients were supplied by Arnon micronutrient composition except Zn, and Zn was supplied with three levels of 0, 0.016, 0.082 mg/L as ZnSO4·7H2O, and CaCO₃ with four rates as 0, 10, 30, 60 mg/L, respectively. The results showed that, the sensitivity of winter wheat plants of five genotypes to Zn deficiency was clarified as follows: S02-8 and Yuanfeng 998 belonged to sensitivity-types to Zn deficiency, and Zhongyu 6, Xiaoyan 22 and Xiza 1 were nonsensitivity types, this classification was mainly based on yield of root and shoot, as well as the extent of occurrence of Zn deficiency symptoms. Supplying Zn with low rate was more favorable forgrowth of wheat plants; Addition of CaCO₃ with low rates could promote the development of wheat plants to some extent, whereas, addition with high rate inhibited the growth. The yield of roots and shoots for wheat plants of sensitivity types were significantly lower than that of non-sensitivity types, and also the ratios of root to shoot of the...