不同pH和供Zn条件下HCO_3~-对冬小麦幼苗生长和锌营养的影响

采用营养液培养法,研究了不同pH和供Zn条件下高浓度HCO3-(10 mmol L-1)对小麦幼苗生长,尤其是对锌营养的影响,结果表明:当营养液起始pH为6时,HCO3-在缺Zn时对小麦根系生长的抑制作用较为明显,而正常供Zn时的影响较小。当营养液起始pH为8时,不论缺Zn还是供Zn,添加HCO3-对根系和地上部均未表现出明显的抑制作用。HCO3-在酸性营养液中能极大促进小麦植株根系和地上部尤其是根系对Zn的吸收,而在碱性条件下则抑制小麦幼苗根系和地上部对Zn的吸收。此外,HCO3-能显著抑制Zn从根系向地上部分的转运,从而造成在根系中的大量积累。HCO3-加入营养液后会生成少量的CO32-,并使营养液pH维持在较高水平上。

Effect of Bicarbonate on Zinc Nutrition of Winter Wheat under Different pH and Zinc Supply

A solution cultivation experiment with winter wheat seedlings was conducted to study the effect of high HCO~-_3 concentration(10 mmol L~(-1)) on wheat growth and zinc uptake at different pH and two Zn supply levels.The results showed that at initial pH 6,HCO~-_3 could obviously inhibit the growth of roots at Zn deficiency,whereas there was nearly no influence on growth at normal zinc supply.At initial pH of 8,the inhibition of HCO~-_3 was unobvious to the growth of roots and shoots of the wheat with or without zinc supply,HCO~-_3 increased dramatically zinc uptake in roots and shoots of the wheat in the acid nutrient solution,especially in the roots,however,HCO~-_3 restricted zinc uptake of roots and shoots of the wheat in the alkaline solutions.In addition,HCO~-_3 significantly inhibited transport of zinc from the roots to shoots,and thus Zn was mainly accumulated in the roots.The addition of HCO~-_3 led to production of small amount of CO~(2-)_3,and maintained the high level to the pH of the nutrient solution.