The Effects Of Compound Salt And Alkali On Physiological Characteristics Of Zhongyan100 In Seedling Period

In view of the increasingly serious salinization of tobacco planting soil,this paper provides a certain theoretical basis for the cultivation practice in order to explore the growth and development of tobacco plants under different saline-alkali conditions.In this study,Zhongyan 100,which has a wide planting area and relatively weak salt tolerance in the national tobacco area,was studied.Using n(Na Cl):n(Na2SO4)=1:1 and n(Na Cl):n(Na2SO4):n(Na HCO3)=1:1:1 to simulate the complex saline-alkali environment.The main results are as follows:(1)Low-concentration salt and saline-alkali treatments could promote the growth of tobacco in a short time,the synthesis of chlorophyll,the utilization efficiency of light,total root surface area and root activity were increased.Under low compound salt concentration,root length,diameter and volume were also promoted.However,compound saline-alkali treatments only had a reduced effect on cell membrane permeability in the 4d after treatment,and the effect was not lasting.(2)The damage of compound salt and saline-alkali to tobacco increased with the increase of treatment time and concentration.Salt and saline-alkali treatment had a strong osmotic stress and membrane lipid peroxidation,The cell membrane,chlorophyll and root system were all damaged,and inhibitory effect increased with the increase of concentration.With elongated treated time,even mild stress could also inhibit the growth of tobacco.(3)The endogenous hormones,organic osmotic regulatory substances and antioxidase systems were regulated rapidly in a short time,but with elongated treated time,the mechanisms were all disordered.During late-phase of treatment,the major substances still active were ABA,POD and proline.Under compound salt condition,the content of soluble sugar,protein and the activity of CAT increased in initial stage and then declined,proline and POD increased continuously.Under compound saline-alkali condition,IAA increased continuously,while proline declined in the late stage.(4)Compound saline-alkali treatments could stimulate the adaptability earlier than compound salt,and were more harmful to tobacco.It resulted leaf wilted earlier and turned yellow,and high saline-alkali treatments caused a large number of root tips to brown and rot.In addition,the decrease of cell membrane permeability,organic osmotic regulatory substances and enzyme activity were much higher than the same compound salt treatment.