镉污染条件下水稻对假单胞菌TCd-1微生物修复的生理响应

微生物在修复重金属污染土壤中发挥重要作用。为阐明假单胞菌TCd-1降低水稻镉吸收的机理，通过加镉土培盆栽试验，在10 mg/kg镉处理下，对比研究了接种菌株对2种镉耐性不同水稻品种(特优671、百香139)镉含量、根系活力、光合作用、抗氧化酶活性及抗氧化物质含量的影响。结果表明：与10 mg/kg镉处理相比，接种假单胞菌TCd-1后水稻“特优671”和“百香139”的根、茎、叶、糙米的镉含量分别依次降低了30.4%、39.1%、40.7%、29.2%和52.2%、51.7%、18.4%、38.8%;提高了2种水稻的根系活力、光合作用，促进了水稻的生长；“特优671”、“百香139”叶片的超氧化物歧化酶(Superoxide dismutase, SOD)活性分别提高了7.3%、138.5%,过氧化物酶(Peroxidase, POD)活性提高了82.0%、106.2%,过氧化氢酶(Catalase, CAT)活性提高了58.8%、172.7%;叶片的类黄酮含量提高了139.4%、73.6%,总酚含量提高了27.2%、23.1%;超氧阴离子含量降低了44.2%、29.0%,丙二醛(Mal...

Physiological response of Rice (Oryza stiva L.) to the microbial remediation by Pseudomonas TCd-1 under cadmium contaminated conditions

When Rice (Oryza stiva L.) is stressed by heavy metal, its growth and development are obviously hindered. The metabolism of rice grown in areas contaminated with heavy metal will change and its growth will slow down, resulting in a decrease in biomass. Among different heavy metals, cadmium is the most harmful to plant growth and human health. Cadmium in the soil is easily absorbed and accumulated by rice, affecting plant growth, cell division and metabolic activities, and causing its yield and quality to decline. Microorganisms play an important role in the remediation of soil contaminated by heavy metal. In this study, Pseudomonas strain TCd-1 was selected from the rhizosphere soil of cadmium-tolerant rice in the early stage of the research group. The Pseudomonas TCd-1 has a strong tolerance to heavy metal cadmium. In this study, two rice species with different cadmium tolerance, Teyou 671 and Baixiang 139, were used as experimental subjects. To elucidate the mechanism of Pseudomonas TCd-1 reducing the cadmium uptake in rice, the effects of inoculated strains on the cadmium content, root vitality, photosynthesis, antioxidant enzyme activity, and antioxidant content of two rice species with different cadmium tolerance were investigated under the stress of 10 mg/kg cadmium. The results suggest that the cadmium contents in the roots, stems, leaves and brown rice of the Teyou 671 decrease by 30.4%, 39.1%, 40.7%, and 29.2%, respectively, while the cadmium content in the roots, stems, leaves, and brown rice of the Baixiang 139 decrease by 52.2%, 51.7%, 18.4%, and 38.8%, respectively, after inoculation with Pseudomonas TCd-1. The root vitality and photosynthesis of the two rice species are improved, leading to promoting the growth of rice. Superoxide dismutase (SOD) activity in the leaves of Teyou 671 and Baixiang 139 increase by 7.3% and 138.5%, Peroxidase (POD) activity increase by 82.0% and 106.2%, Catalase (CAT) activity increase by 58.8% and 172.7%, the flavonoids content in the leaves of two rice species with different cadmium tolerance increase by 139.4% and 73.6%, the total phenol content increase by 27.2% and 23.1%, the superoxide anion content decrease by 44.2% and 29.0%, and the Malondialdehyde (MDA) content in the leaves of two rice species decrease by 38.5% and 28.9%, respectively, in comparison with the treatment of 10 mg/kg cadmium. In conclusion, for two rice species with different cadmium tolerance, after inoculation of Pseudomonas TCd-1 can increase the antioxidant capacity of Teyou 671 and Baixiang 139 with different cadmium tolerance, reduce the oxidative stress, and promote the growth of two rice species with different cadmium tolerance.