Study On The Mitigation Mechanism Of Cadmium Toxicity Of Male And Female Populus Cathayana By Silicon

During the long evolutionary process of dioecious plants,there have been significant differences in physiology and biochemistry,growth status,resource allocation,reproduction methods,and spatial distribution among dioecious plants of different plants,and numerous response mechanisms have emerged to adverse environmental stresses.Populus cathayana is widely used in the practical operation of remediation of heavy metal contaminated soil.At the same time,P.cathayana has good practicality,economic value,and ecological value.P.cathayana is widely used as a greening plant,and its application to improve and beautify the ecological environment can have significant effects.The northern region of China has a vast territory and a distinct climate in four seasons,which is very suitable for the growth of poplar and has extremely abundant poplar resources.Poplar is easy to grow,easy to survive by cutting,and has a fast growth rate and a large biomass.It has a high resistance to heavy metal stress and a strong ability to enrich metals.In addition,some aboveground tissues facilitate later processing,harvesting,and collection.Therefore,it is widely used as a tree species for industrial timber,ecological protection forests,and remediation of heavy metal contaminated soil.Cadmium(Cd)is a non essential element for animals and plants.Cd has strong toxicity,which is not only detrimental to the growth of plants,but also can enter the human body through the accumulation of the food chain,damaging the normal functions of the human body,damaging the immune system,causing organ cancer and even causing genetic defects.After entering the material cycle,Cd is harmful to human health,and the problem of Cd pollution needs to be addressed urgently.In the study of alleviating the toxicity of Cd to plants,Silicon(Si)plays a crucial role.Si has a good inhibitory effect on the absorption,transportation,and accumulation of Cd in plants.For example,exogenous application of Si is beneficial to the growth and development of plants,can strengthen the antioxidant system,reduce the damage of reactive oxygen species to plant cells,reduce the transport of Cd to the aboveground portion,and reduce the bioavailability of Cd in the rhizosphere soil,thereby reducing the absorption of Cd by plants,Alleviate the toxicity of Cd to plants.In this study,female and male cuttings were selected as materials for research.The biomass,photosynthetic indicators,root activity,root morphology,leaf cell ultrastructure,oxide content,antioxidant enzyme activity,non enzymatic scavenging system content,Cd content in each part of the plant,cell wall Cd content in each part of the plant,and Cd morphology in the rhizosphere soil of the poplar were measured to explore the mitigation mechanism of Si toxicity to female and male poplar.The main conclusions are as follows:(1)Effects of Si on physiological growth of males and females under Cd Stress By measuring plant biomass,photosynthetic indicators,root activity,root morphology,and leaf cell ultrastructure of male and female P.cathayana,the differences in physiological growth of males and females Populus cathayensis under Cd stress were clarified.The results showed that under Cd stress,the biomass and photosynthetic index of female plants decreased significantly compared to male plants,the root activity decreased and the morphology appeared abnormal.Under Cd stress,the ultrastructure of the leaf cells of both male and female poplar was severely damaged,and the cell walls and organelles were deformed and disintegrated to varying degrees.The damage of female plants was more severe than that of male plants.The adverse effects of Cd stress on the growth and physiology of female plants were greater than that of male plants,and the female plants were more sensitive to Cd stress,Male poplar showed stronger resistance to Cd stress,with significant differences between male and female.After applying Si,the physiological growth indicators of female plants were significantly alleviated compared to male plants.(2)Effects of Si on antioxidant system of males and females under Cd Stress By measuring the oxide content,antioxidant enzyme activity,and non enzymatic scavenging system content of males and females Populus cathayensis,the differences in the antioxidant system of males and females Populus cathayensis in alleviating Cd stress were clarified.The results showed that under Cd stress,the oxide content in both male and female plants significantly increased to varying degrees,the non enzyme scavenging system was damaged,and the enzyme activity was affected.Experimental data showed that female plants were more severely stressed,and the negative impact of Cd stress on the antioxidant system of female plants was significantly greater than that of male plants.Female plants were more sensitive to Cd stress,and male plants had strong resistance to stress,with significant differences between male and female plants,Male poplar showed stronger resistance to Cd stress.After Si application,the antioxidant enzyme activity of female plants significantly increased,the non enzymatic scavenging system eased,and the oxide content decreased significantly compared to male plants.(3)Effects of Si on Cd uptake,transport,and rhizosphere Cd morphology of males and females under Cd stressBy measuring the Cd content in each part of the plant,the cell wall Cd content in each part of the plant,and the Cd morphology in the rhizosphere soil of males and females Populus ussuriensis,it was clear that Si application alleviated the differences in Cd accumulation and transport between males and females Populus ussuriensis and the Cd morphology in the rhizosphere soil.The results showed that under Cd stress,male plants tended to accumulate Cd in the underground part,while female plants tended to transport Cd to the aboveground part.Female plants were more sensitive to Cd stress,and male plants showed strong tolerance to Cd stress.There was a significant difference between male and female plants.After applying Si,the number of Cd transport lines from female plants to the aboveground part significantly decreased,and the proportion of available Cd in the rhizosphere soil decreased.Si application reduced the difference between male and female plants under Cd stress.