Effects of Cd on Seedling Growth and Phytohormone Contents of Glycine max

TLDR: There were significant relationships between Cd concentrations and the ratios of ABA/IAA,ABA/GA3 and A BA/Z, indicating that Cd stress influenced not only the content of phytohormones but also their ratios and balance.

Abstract: Pot experiment was conducted to study the effects of different Cd concentrations on seedling growth and the contents of indoleacetic acid(IAA),gibbrellins(GA3),zeatin(Z) and abscisic acid(ABA) of Glycine max plant by high performance liquid chromatography(HPLC) analytical method.The results indicated that the plant height and aboveground biomass of seedlings were not affected significantly by the lower Cd concentrations(≤0.50 mg·kg-1) but inhibited markedly at the higher Cd concentrations(≥2.50 mg·kg-1).However,at 0.50 mg·kg-1 of Cd concentration,the biomass of aerial parts in blooming period and root biomass were inhibited significantly.Cd stress inhibited the synthesis of indoleacetic acid(IAA) and zeatin(Z) at 0.25 mg·kg-1 of Cd concentration,and the contents of IAA and Z in leaves were 43.1% and 75.5% and 60.6% and 32.6% of that of the control in seedling and blooming period respectively.Cd could stimulate the synthesis of abscisic acid(ABA),when Cd concentration was 2.50 mg·kg-1,the contents of ABA in leaves in seedling and blooming period were 13.6 times and 3.86 times of that of the control respectively.The synthesis of gibbrellins(GA3) was stimulated at the lower Cd concentration(≤0.25 mg·kg-1) but was inhibited at the higher Cd concentration.There were significant relationships between Cd concentrations and the ratios of ABA/IAA,ABA/GA3 and ABA/Z,indicating that Cd stress influenced not only the content of phytohormones but also their ratios and balance.