镉胁迫对谷子、糜子和高粱幼苗形态及生理特性的影响OA

To investigate the responses of foxtail millet,broomcorn millet,and sorghum seedlings to cadmium stress,in this study,Jingu 21(foxtail millet),Yumi 2(broomcorn millet),and Liaoza 27(sorghum)were used as experimental materials.These plants were subjected to cadmium stress treatments with 0 and 300 μmol/L CdCl2.Indicators such as plant height,aboveground dry weight,underground dry weight,photosynthetic characteristics,and chloroplast fluorescence characteristics were measured.The cadmium tolerance of the three crops was comprehensively evaluated using principal component analysis and membership function method.The results showed that cadmium stress significantly inhibited the growth and development of foxtail millet,broomcorn millet,and sorghum,with interspecific differences in the inhibitory effects.Among them,cadmium stress had the most significant inhibitory effect on the plant height of foxtail millet,the strongest inhibitory effect on the aboveground dry weight and underground dry weight of broomcorn millet,and a weaker inhibitory effect on the plant height,aboveground dry weight and underground dry weight of sorghum.Cadmium stress reduced the leaf photosynthetic performance of the three crops.After 5 days of cadmium stress treatment,the decrease in net photosynthetic rate(Pn)of sorghum was smaller than that of foxtail millet and broomcorn millet.Cadmium stress had varying effects on the chlorophyll fluorescence parameters of the three crops.It reduced the initial fluorescence(F0),maximum fluorescence yield(Fm),actual photochemical efficiency(ФPSⅡ),and non-photochemical quenching coefficient(qN)of broomcorn millet and foxtail millet leaves.In contrast,the initial fluorescence,maximum fluorescence yield,actual photochemical efficiency,and non-photochemical quenching coefficient of sorghum leaves increased by 39.66%,25.44%,12.40%,and 56.25%,respectively,compared to the control,and the decrease in maximum photochemical efficiency(Fv/Fm)was smaller than that of foxtail millet and broomcorn millet.Principal component analysis of 12 indicators from the three crops revealed that the five indicators including underground dry weight,plant height,F0,Fm,and transpiration rate(Tr)could be used as the key indicators to evaluate the cadmium tolerance of the three crops.Membership function analysis results indicated that the cadmium tolerance of the three crops,from strongest to weakest,was as follows:sorghum>foxtail millet>broomcorn millet.In summary,under cadmium stress,Liaoza 27 maintained higher photosynthetic efficiency and adapted to the cadmium-stressed environment by enhancing thermal dissipation,thereby preserving better growth characteristics.Therefore,Liaoza 27 was more suitable for cultivation in cadmium-polluted areas of northern Shaanxi.