Response Of Seed Germination And Seedling Growth Of Jujube To Water And Salt Stress

Ziziphus acidojujuba var.spinosa has the characteristics of drought tolerance and salt tolerance.Its planting area in Hebei Province is continuously expanding.Due to the shortage of water resources in Hebei Province,the agricultural water consumption is large and the water use efficiency is low.At the same time,the brackish water reserves in Hebei Province are abundant and easy to exploit.Therefore,this paper takes "Xing suan No.15" as the experimental material,and uses the rational use of brackish water to save fresh water resources,and studies the response of jujube seed germination and seedling growth to water and salt stress,and explores the combination of irrigation water saving and salt stress.The irrigation mode has good theoretical and practical value for understanding the drought tolerance,salt tolerance and utilization of brackish water.The results of this study are as follows:(1)Under salt stress,the germination rate,germination potential,germination index,vigor index and hypocotyl length and radicle length of jujube seed were all inhibited.Adding moderate(0.25~1.5 mmol/L)salicylic acid can increase seed germination.When salicylic acid concentration is 1.0 mmol/L,the seed germination effect of jujube seed is best.When the salicylic acid concentration is 2.0 mmol/L,the salt damage of the jujube seeds is aggravated.(2)During the test treatment period,the water consumption of the jujube seedlings was similar,showing a single-peak curve fluctuation.From late July to early August,the water consumption of jujube was the largest,and the water consumption in this period accounted for 33.60%~39.74% of the whole treatment period.The salt content significantly inhibited the water consumption of jujube seedlings.The water consumption and water consumption intensity decreased with the increase of irrigation salt concentration.When the salt concentration was greater than or equal to 200 mmol/L,the water consumption of jujube seedlings was significantly lower than other treatments.Under the same salt concentration,the water consumption and water consumption intensity of jujube seedlings increased with the increase of irrigation amount.(3)With the increase of salinity concentration of irrigation water and the decrease of irrigation amount,the plant height,stem diameter,leaf area and dry matter accumulation of jujube seedlings showed a downward trend.Under medium and high water irrigation conditions,when the salt concentration is less than or equal to 50 mmol/L,the leaf area of jujube seedlings is significantly higher than other treatments.Under high water and high salt treatment,water loss,yellow leaves and shedding will occur earlier.When the salt concentration exceeds 200 mmol/L,irrigation has no significant effect on dry matter accumulation.(4)The chlorophyll content,net photosynthetic rate,stomatal conductance and transpiration rate of leaves of jujube seedlings decreased significantly with the increase of irrigation salt concentration.When the salt concentration was less than or equal to 50 mmol/L,the net photosynthetic rate and transpiration rate of high water treatment leaves were significantly higher than that of low water treatment.The water use efficiency of low water treatment leaves was higher than that of medium water and high water treatment.Under the condition of medium and high water treatment,with the increase of salt concentration,the water use efficiency was the highest when the salt concentration was 150 mmol/L.In conclusion,the irrigation amount of jujube seedlings is 80% Aw,(Aw=(90%-70%)field water holding capacity)and the concentration of irrigation salt is about 50 mmol/L.The jujube seedlings can grow normally,and the inhibition effect of salt on the growth and development of jujube seedlings is not obvious.When the concentration of irrigation salt continues to increase,jujube seedlings continue to increase.It is greatly affected by salt.