| The total area of saline alkali land in China is about 99.13 million hectares.Soil salinization has seriously restricted the development of agricultural production in China.Cultivated barnyardgrass(Echinochloa frumentacea)is a salt tolerant crop.It is of great significance to study the growth and salt-alkali tolerant of cultivated barnyardgrass in cold region for the utilization and improvement of saline-alkali soil resources in Heilongjiang Province.This study includes three experiments:1)Germination experiment of salt resistance,alkali resistance of seeds.Through the method of Petri dish germination,sodium chloride and sodium bicarbonate were set at four levels(0,100,200,300 and 400 mmol·L-1solution)respectively;2)In pot experiment,barnyardgrass and maize were planted on black soil and soda saline alkali soil respectively;3)In field experiment,barnyardgrass and maize were planted in the experimental site of the school.After emergence,sodium bicarbonate and sodium carbonate were added to simulate saline alkali soil to simulate saline alkali soil.The main results are as follows:(1)The cultivated barnyardgrass seeds has strong salt tolerance,alkali resistance.The 100mmol·L-1sodium chloride solution did not affect the germination rate.The germination rate,germination potential,germination index and vigor index of barnyard seeds decreased with the further increase of stress intensity.(2)The plant height,leaf area and dry matter weight of cultivated barnyardgrass in the northeast cold region showed a rapid upward trend,which could be described by logistic equation Y=K/(1+EXP(a-b X)).The contents of nitrogen,phosphorus and potassium in different organs of cultivated barnyardgrass in black soil decreased gradually with the its growth and development,while the total accumulation increased gradually.The content of Na+in all organs of cultivated barnyardgrass was significantly increased under saline alkali stress,while the content of K+was significantly decreased.The proportion of Na+in stem and leaf sheath was increased.The value of Na+/K+in all organs of Echinochloa crusgalli cultivated in saline alkali soil was higher than that cultivated in black soil.The value of Na+/K+in stem and leaf sheath of cultivated Echinochloa crusgalli was higher than that of other organs under saline alkali stress,and the absorption of Na+by stem and leaf sheath was selective.(3)The activity of superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT)of cultivated barnyardgrass were increased under salt alkali stress,but the increase rate was less than that of maize.The content of chlorophyll in the leaves of cultivated barnyardgrass was decreased by salt alkali stress,but the decrease rate was smaller than that of maize,and the salt-alkali resistance of cultivated barnyardgrass was higher than that of maize.The content of malondialdehyde(MDA)and soluble sugar were increased by salt alkali stress,but the difference with control were not significant.The effect of salt alkali stress on membrane lipid oxidation was less in cultivated barnyardgrass.In the light response curve,the apparent electron transfer rate(ETR)and actual quantum yield(Y II)of cultivated barnyardgrass and maize were decreased by salt alkali stress,but the decrease rate in cultivated barnyardgrass was smaller than that in maize.Meanwhile,the YNO and YNPQ of cultivated barnyardgrass and maize increased,and the increase range in cultivated barnyardgrass was larger than that in maize.In the induction curve,the Y(II),ETR and q P values of cultivated barnyardgrass and maize were decreased by salt alkali stress,the decrease rate of cultivated barnyardgrass was smaller than that of maize,and the Fv/Fm of both increased at the same time.The increase rate of cultivated barnyardgrass was higher than that of maize.NPQ of cultivated barnyardgrass increased by the stress,and that of maize showed a decrease.The light energy utilization ability and its protection ability of cultivated barnyardgrass were higher than that of maize. |
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