Physiological And Anatomical Differences Between Nicotiana Tobacco And Rustic Tobacco Under Cadmium Stress

In recent years,with the aggravation of environmental pollution,the harm caused by heavy metal pollution has caused widespread concern.Tobacco is a kind of crop which is easy to accumulate cadmium.In recent years,the research on tobacco cadmium has become one of the hotspots in the world.This experiment with Nicotiana tobacco K326 and Rustic tobacco N.rusticafor materials on the antioxidant system,endogenous hormones and anatomical structure were studied to investigate the effects and mechanism of Nicotiana tobacco and Rustictobacco in low concentrations of cadmium stress.The hydroponic experiment results show that:Cd stress significantly increased SOD coerced forced activity of N.rustica in roots,Nicotiana tobacco K326 decreased;The activity of SOD in leaves of Nicotiana tobacco K326 showed an upward trend and N.rustica decreased obviously.CAT activity in roots and leaves of rustic tobacco N.rustica increased significantly.There was no significant change in CAT activity in the roots of K326,and the leaf increased slightly.The activity of POD,GR and MDA in two different genotypes tobacco showed an upward trend in their roots and leaves.The contents of IAA in tobacco roots and leaves of two different genotypes were increased under cadmium stress.There was no significant difference in ABA content between the root of Nicotiana tobacco K326 and the photograph,ABA content in leaves of Nicotiana tobacco K326 showed an upward trend;The content of ABA in roots and leaves of Rustic tobacco N.rustica increased.The content of GA3 in leaves of Rustic tobacco N.rustica was increased compared with that of photograph;There was no significant change in GA3 content in the leaves of Nicotiana tobacco K326.The content of ZR in the roots of Nicotiana tobacco K326 decreased,and there was no significant change in the leaves;The content of ZR in roots and leaves of Rustic tobacco N.rustica increased.Under Cd stress,the thickness of K326 leaf,upper epidermis thickness,palisade tissue thickness and spongy tissue thickness increased,the thickness of Rustic tobacco N.rustica leaf,upper and lower epidermis thickness,spongy tissue thickness decreased;The CTR and P/S values of Nicotianatobacco K326 leaves decreased with the increase of SR value,Rustic tobacco N.rustica leaves opposite Nicotiana tobacco K326.After Cd treatment,Nicotiana tobacco K326 leaf epidermal cells were shrunken,stomatal conductance increased,significantly reduced trichome;After Cd treatment,Rustic tobacco N.rustica leaf epidermal cells were shrunken,stomatal conductance increased,glandular hairs increased.