A Preliminary Study On Hemin-Induced Resistance To Salt Stress And Alkaline Stress In Tobacco

Tobacco(Nicotiana tabacum l.)is a plant of the solanaceae family,and it is easy to be stressed by drought,heavy metal,saline-alkali,etc.,and seriously affect the growth of tobacco.Hemin is a highly effective inducer that can induce plants to resist multiple abiotic stresses.This study introduced the influence of hemin in the tobacco growth and physiological characteristics under salt stress and alkali stress and attempted to explore the mechanism through antioxidant system,osmotic adjustment system,ion contents and related gene expression,and also the effects of hemin and P-CDH on tobacco growth under salt stress were simply investigated.The results were shown as follows.1.The salt stress at different concentrations inhibited the growth of tobacco seedlings at the age of 12d,and the elongation of the main root became shorter.Pretreatment with 1,10,100 mol/L hemin and 0.01,0.1,1 mol/L ?-CDH can significantly improve this phenomenon,and the pretreatment with 10 mol/L hemin and 0.1 mol/L ?-CDH has the best effect on tobacco growth under salt stress.The chlorophyll content of tobacco under salt stress can be significantly increased by pretreatment with mol/L hemin and 0.1 mol/L p-CDH.2.1 ?mol/L hemin and 2 ?mol/L hemin could promote the growth,increase the fresh weight,root length,photosynthetic pigments content and root activity of tobacco under alkali stress.Hemin could reduce malondialdehyde(MDA)content,relative conductivity,ascorbic acid(AsA)and glutathione(GSH)content,and increase the superoxide dismutase(SOD),peroxidase(POD),catalase(CAT)and ascorbic acid reductase(APX)activity.Hemin also co increase the contents of proline,soluble sugar,soluble protein.Hemin treatment could reduce Na+ accumulation and increase the absorption of K+,Ca2+,Mg2+.Real-time relative quantitative PCR results showed that hemin could induce NtPDR1,NtPDR3,NtNAC and NtGSH1 gene expression.The above results indicated that hemin and ?--CDH pretreatment can alleviate the growth inhibition of salt-stressed tobacco,and hemin relieve the damage of tobacco under alkali stress result from the combined effects of stimulating antioxidant and osmotic regulation system,strengthening ion transport and adjusting related genes expression.