Effects Of Cadmium And Nitrogen On Morphological,Physiological And Biochemical Characteristics Of Male And Female Seedlings Of Populus Deltoides ×P.nigra Cv.chile

With the rapid development of industry and agriculture around the world,soil cadmium pollution and atmospheric nitrogen deposition are becoming more and more serious.Dioecious species are one of the important components of terrestrial ecosystems.The study of dioecious plants has important significance.Different genders have different physiological responses when dealing with environmental changes.In this study,Populus deltoides×P.nigra cv.Chile were used as research objects,and the soil cadmium concentration was treated(control C 0.004 mg·kg-1;exogenous cadmium added M 100 mg·kg-1)and spraying ammonium nitrate to simulate nitrogen deposition(Control C 0 kg·hm-2·a-1;exogenous nitrogen added N 90 kg·hm-2·a-1)and their interaction treatments were used to study the differences in morphology and physiology of male and female plants.The main findings are as follows:1:Under the cadmium treatment alone,the biomass of the male and female seedlings of the southern four seasons was significantly lower than that of the control,and the decline rate of the male plants was significantly higher than that of the female plants.Under the condition of nitrogen deposition,the biomass of both sexes increased significantly,and the female plants increased.Greater than male plants.Under the interaction,nitrogen deposition slowed down the biomass of female plants.Compared with cadmium treatment alone,the stem biomass and total biomass of female plants increased significantly,while male plants showed no significant changes.2:In terms of gas exchange and fluorescence parameters,the net photosynthetic rate(Pn),photochemical quenching coefficient(qP)and effective photosynthetic quantum yield(YII)of the two sex plants decreased significantly after cadmium treatment,and the non-photochemical quenching coefficient(NPQ)significantly rising.The Pn,water use efficiency(WUE),stomatal conductance(gs)and transpiration rate(Tr)of male plants were larger than that of female plants under cadmium treatment alone,and the increase of NPQ was smaller than that of female plants.Under the condition of nitrogen deposition,the gs and Pn of the two kinds of seedlings increased significantly,and the male plants were more obvious,and the Tr of the male plants increased significantly and the female plants Tr did not change significantly.Under the interaction treatment,the Pn,WUE and NPQ of the male plants increased significantly compared with the cadmium treatment alone3:The cadmium treatment alone increased the activity of superoxide dismutase(SOD)in the female plants of the plant,while the SOD activity of the male plants decreased significantly and was significantly lower than that of the female plants.The soluble protein(SP)content of the male plants decreased significantly.The content of malondialdehyde(MDA)in the oxidation product increased significantly,while the content of SP and MDA in female plants did not change significantly.The content of proline(PRO)in female plants increased significantly under cadmium treatment alone,while the PRO content of male plants did not change significantly.Under the condition of nitrogen deposition,the soluble protein content of both sexes increased significantly.The PRO content of the female plants under the interaction treatment increased significantly compared with the cadmium treatment alone.4:Under the cadmium treatment and interaction conditions,the root surface area and root length of the Populus deltoides ×P.nigra cv.Chile of the plant were significantly decreased.The diameter of roots of female plants decreased significantly under cadmium treatment alone,while the diameter of roots increased significantly under interactive conditions.The root diameter of male plants did not change significantly under cadmium treatment and interaction conditions.The results showed that cadmium treatment slowed the growth of male and female seedlings of Populus deltoides ×P.nigra cv.Chile,hindered gas exchange,photosystem ? was damaged to some extent,the antioxidant enzyme system was disturbed and root growth was inhibited,and the tolerance of cadmium treatment between genders was inconsistent.Male plants are more stressed than female plants.Nitrogen deposition promoted the growth of seedlings of both sexes to some extent.Nitrogen deposition under the interaction treatment reduced the toxic effect of cadmium on Populus deltoides×P.nigra cv.Chile,and reduced the difference in cadmium toxicity between sexes..