Abstract: The objective was to research the physiological function of CPK6 in Ca²⁺ signal transduction and to reveal the mechanism of plants to adapt to Ca²⁺ deficient environment. By homozygous identification of the CPK6 deletion mutant (cpk6), two homozygous mutants, cpk6-2 and cpk6-3 were obtained. And the growth phenotype of wild-type Arabidopsis Col-0 and cpk6 mutants in the deficiency of Ca²⁺, Fe²⁺, Mg²⁺, Zn²⁺ and Mn²⁺ were analyzed. The results showed that the mutants showed a growth-inhibiting phenotype relative to wild-type Col-0 in the deficiency of Ca²⁺. The Arabidopsis transgenic material expressing CPK6 promoter-driven β-glucuronidase were obtained. Using GUS histochemical staining, it was found that CPK6 promoter had activity in the roots and the growth point of the leaves. And the activity of CPK6 promoter in leaves was visibly enhanced under Ca²⁺ deficient condition. The total Ca content of Col-0 and cpk6 was determined by atomic absorption spectrometry (AAS). It was found that there was no significant difference in Ca content between Col-0 and cpk6 under control and Ca²⁺ deficiency conditions. The results indicated that CPK6 gene did not participate in the absorption and accumulation of Ca in Arabidopsis. Using histochemical staining and fluorescent probes methods, it was found that the accumulation of H₂O₂ in the leaves and roots of cpk6 was visibly higher than that in Col-0 under Ca²⁺ deficient condition. The results showed that CPK6 was a negative regulator of the accumulation of H₂O₂ induced by Ca²⁺ deficiency in plants.

Key words: Ca²⁺, Arabidopsis thaliana, CPK6, GUS, H₂O₂

CLC Number: 

• Q945.78