Accumulation And Response Of Three Sweet Sorghum Varieties Under Cd And Pb Stress

There is a large area of heavy metal pollution of the land in China,because its biological effects of poison is not suitable for planting into the food chain crops,if used for develop energy crops,Not only solve the energy crisis,but also a certain degree of environmental repair role.Sweet sorghum is the most ideal energy crops,How its tolerance?What kind of enrichment capacity?These problems remain to be solved Are to be solved.In this Test,three kinds of sweet sorghum were used as experimental materials to study the effects of different concentrations of Cd and Pb on the germination,growth and development,physiological characteristics and enrichment of three kinds of sweet sorghum by germination toxicology test and potting toxicology test.The Cd-tolerance and Pb-tolerance of three kinds of sweet sorghum were evaluated by assignment method.The main,results are as follows:?1?The germination potential,germination rate,germination index,vigor index,root length and bud length of three kinds of sweet sorghum decreased with the increaseing of heavy metal Cd and Pb concentration.When Cd concentration was less than 0.30 mmol·L-1,the germination potential and germination rate of Jintianza 1 were significantly higher than control group,and these shows the promoting effect.The Falling range of different varieties was different under the different concentrations of Cd and Pb.And it was difficult to judge the resistance.Therefore,Cadmium tolerance and lead tolerance of Jintianza 2 was the strongest,which was evaluated by the comprehensive evaluation of the resistance during germination stage.At the same time,three sweet sorghum seedlings were observed in the pot experiment,and the strong resistance of Jintianza 2 was found in the sweet sorghum variety.?2?The changes of plant growth and development of three sweet sorghum from emergence to adult stage were observed.the plant height,LAI and dry matter accumulation were inhibited under Cd and Pb stress,and the inhibitory effect was more obvious with the increase of concentration.The growth and development of three kinds of sweet sorghum were different under Cd and Pb stress,and the resistance of different cultivars of Cd and Pb was different.The net assimilation rate of Cd and Pb decreased with the increase of heavy metal at the earlier stage,and higher Cd and Pb stress later than control.At the earlier growth stage,combined with the above analysis of plant height,leaf area index and dry matter accumulation under Cd and Pb stress,it was found that the plant was sensitive to Cd and Pb stress,and the resistance was weak,Under the stress,three kinds of sweet sorghum Growth to adult-plant stage compare with the control the difference was narrow,and the difference between the some indexes was not significant.?3?In the aspect of physiological characteristics,the contents of chlorophyll a,chlorophyll b and chlorophyll decreased with the increase of Cd and Pb concentrations at seedling stage and jointing stage,while the relative conductivity,MDA,proline content and POD activity increased trend.The chlorophyll a/b values increased with the increase of Cd and Pb stress due to the different decomposition rates of chlorophyll a and chlorophyll b.When Cd content is 7 mg·kg^-1 at the seedling stage,the activity of POD was lower than that of the control group,which Fall by 10.29%and 24.09%,respectively.At the same time,the difference of physiological resistance was evaluated by using the method of assignment in seedling period and jointing period.The resistance to cadmium was in the order of Jintianza 3,Jintianza 2,Lead strongest,seedling period Jintianza 2 stronger than Jintianza 1,jointing period Jin sweet miscellaneous No.1 stronger than Jin sweet miscellaneous 2.?4?Cd and Pb contents of three sweet sorghum single plant and their organs were significantly different under Cd and Pb stress.The content of Cd in single plant was 1.45 mg·kg^-1,and the content of stem was 1.16 mg·kg^-1 in Cd concentration of 3 mg·kg^-1.The content of Pb was the highest in the Pb concentration of 500 mg · kg^-1,the content was 104.27 mg · kg^-1,and the root content was 330.91 mg · kg^-1.The enrichment ability was also affected by the biomass,because the root system was difficult to collect,only the aboveground part was considered.The accumulation amount of aboveground parts of three varieties,the accumulation of Cd was higher than Jintianza 1,and the accumulation of Pb was higher than Jintianza 3.To summarise,Jintianza 3 is stronger in the early?early seedling stage and jointing stage?of growing heavy metals,and the heavy metal accumulation of Pb is larger,which is the preferred varieties for Pb pollution in the most sensitive period.Because of its large accumulation of heavy metal Cd,Jintianza 1 is the first choice,and the resistance of the varieties was poor.