Studies On Changes Of Physiological Characteristics Of Mulberry Seedlings From Four Provenances Under Salt Stress

Research on the improvement and utilization of saline-alkali land has always been an important area concerned by the science and technology community.Mulberry is reported to be a tree species with extremely high economic value,which at the same time is widely used in greening and ecological protection.However,studies on salt and alkali tolerance of mulberry actually is rarely reported.So,this article selects four different provenances of mulberry seedlings to compare their salt stress response and changes related to physiological indicators,aiming to lay the foundation for exploring the selection and breeding of salt-tolerant mulberry varieties.zShaanXi,Hebei,Inner Mongolia,and Heilongjiang,these four provinces,are chosen as the provenances talked in this article.With process to different NaCl concentrations(control CK,0.1%,0.3%,0.5%,0.7%,0.9%)and different stress durations of 7d,14d,21d,27 d,this article has measured changes in indicators of these four provenances in salt damage index(SI),plant height(H),malondialdehyde(MDA),peroxidase(POD),superoxide dismutase(SOD),soluble sugar(SS),and solubility of four provenances Protein(SP),chlorophyll a(Chla),chlorophyll b(Chlb),total chlorophyll(Chla+b),net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO2(Ci),transpiration rate(Tr).And the main findings are as following:1.All the four provenance mulberry seedlings increase with the rise of the stress time and salt concentration,and the differences among different species are obvious.The growth rate of plant height decreases with the rise of stress time and salt concentration.While the growth rate of plant height decreases with the rise of the stress time and the salt concentration.2.Under salt stress,The MDA activities of the four provenance mulberry seedlings show an going-up trend with dropping-off salt concentration and prolonged stress time.Besides,SOD and POD activities show a tendency of a first going up and then a dropping off with rising salt concentration.3.The SS content of the four provenance mulberry seedlings under salt stress augments first and then reduces with rising salt concentration.The overall SP content shows a gradual reduction with the rise of salt concentration.The mulberry seedlings from Heilongjiang provenance shows a trend of first an augmentation and then a reduction with increasing salt concentration.4.With the growth of the salt concentration and stress time,the content of Chlorophyll a,chlorophyll b,and chlorophyll itself in mulberry seedlings from four provenances show a gradual decline trend.5.Under the salt stress,the net photosynthetic rate(Pn),transpiration rate(Tr),and stomatal conductance(Gs)of the four provenance mulberry seedlings show a general downward trend with increasing salt concentration.The overall intercellular CO2(Ci)concentration of mulberry seedlings from four provenances show an upward trend.During the experiment,the net photosynthetic rate(Pn)of the four provenance mulberry seedlings is not significantly different from the control group(T0)when the salt concentration is T1.And,with the increase of salt concentration,salt has a significant inhibitory effect on mulberry seedlings.6.Preliminary judgment based on comprehensive effects of salt stress on physiological characteristics of mulberry seedlings is that the strength of mulberry seedlings from four provenances will be:Heilongjiang provenance>Inner Mongolia provenance>Shaanxi provenance>Hebei provenance.