Effects Of Grafting Of Different Rootstocks On Physiological Indexes Of Cucumber Under Soil Salinization Conditions

The threat of soil salinization to agriculture is a global problem.The saline soil in the world is about 1×10~9hm~2,accounting for 7%of the total land area,and about 5%of the 1.5×10~9hm~2cultivated land is affected by salt damage.Cucumber(Cucumissativus L.)is a salt-sensitive vegetable,and its growth and yield will be seriously affected under soil salinization conditions.Grafting cultivation can effectively enhance the stress resistance of cucumber and is widely used in production.In this experiment,under the condition of soil salinization,two kinds of cucumbers Zhen Liang 7188 and Zhen Liang 7388 were used as scions,and four kinds of pumpkins Ba Tu 613,Ba Tu 430,Ba Tu 730 and Zhen Zhuang 1949 were used as rootstocks for grafting.The 28d chlorophyll,osmotic adjustment substances,active oxidation scavenging system,and defensive enzyme activity were determined to determine the effects of different rootstock grafting on cucumber physiological indicators and salt tolerance under soil salinization conditions.This study reveals the changes of physiological indicators of different rootstocks grafted,and provides a theoretical basis for the changes of physiological indicators of cucumber grafted on different rootstocks under soil salinization conditions.The main results are as follows:1.The survival rate of grafting with different rootstocks was higher than 90%.Among them,Zhen Liang 7188 cucumber was used as a scion,and rootstocks of Ba Tu430 and Ba Tu730 had the highest graft survival rate;Zhen Liang 7388 cucumber was used as a scion,and rootstocks of Ba Tu 730 had the highest graft survival rate.2.Under the condition of soil salinization,the chlorophyll content of grafted cucumber plants with different rootstocks was compared.The results showed that the chlorophyll content increased first and then decreased with the growth of cucumber.The chlorophyll content of grafted cucumber is higher than that of self-rooted seedlings,but the chlorophyll content of different rootstock and scion combinations is different.Among them,Zhen Liang 7188 cucumber was used as scion,and Ba Tu 613 rootstock grafted treatment showed outstanding chlorophyll content;Zhen Liang 7388 cucumber was used as scion,and Ba Tu 613 rootstock grafted treatment showed outstanding chlorophyll content.It shows that grafting can increase the chlorophyll content and salt tolerance of cucumber leaves,and different rootstocks have slightly different chlorophyll content of cucumber leaves.In this experiment,Ba Tu 613 pumpkin is the most suitable rootstock.3.Under the condition of soil salinization,the content of osmotic adjustment substances in grafted cucumber plants with different rootstocks.The results showed that with the growth of the plant,the content of soluble sugar,free proline and soluble protein in cucumber leaves showed a trend of increasing first and then decreasing.The contents of soluble sugar,free proline and soluble protein in grafted cucumber leaves were higher than those of self-rooted seedlings.As a scion,Zhen Liang 7188 cucumber,Ba Tu 613 rootstock grafting treatment had the highest osmotic adjustment substance content;Zhen Liang 7388 cucumber as a scion,Ba Tu 613 rootstock grafting treatment had the highest osmotic adjustment substance content.It shows that grafting can increase the content of cucumber osmotic adjustment substances.Grafting improves the salt tolerance of cucumber,but the content of osmotic adjustment substances is different for different stocks and stocks.In this experiment,Ba Tu 613 pumpkin is more suitable as a rootstock.4.Under the condition of soil salinization,the changes of active oxidation scavenging system in cucumber plants grafted on different rootstocks.The results showed that with the growth of the plant,the activities of SOD,CAT,POD,and APX of cucumber showed a trend of increasing first and then decreasing.The protective enzyme activities of cucumber leaves in the treatment of grafting with 4 kinds of rootstocks were all increased,which reduced the damage to cucumber plants caused by adversity stress.Among them,Zhen Liang 7188 cucumber was used as scion and Ba Tu 613 rootstock had the highest protective enzyme activity;Zhen Liang 7388cucumber was used as scion,and Ba Tu 613 rootstock had the highest protective enzyme activity.The MDA content of self-rooted seedlings was higher than that of grafted plants.It shows that the resistance of cucumber plants can be improved by grafting,thereby improving the salt tolerance of cucumber.However,there are certain differences in the improvement of cucumber salt tolerance by different rootstock combinations.In this experiment,Ba Tu 613 rootstock grafting showed strong salt tolerance.Under the condition of soil salinization,the root vitality of cucumber plants grafted on different rootstocks is different.The results showed that the root vitality showed an upward trend and then a downward trend with the growth of the plant.The root vigor of grafted plants was significantly higher than that of self-rooted seedlings.Among them,Zhen Liang 7188 cucumber was used as a scion,Ba Tu 613 rootstock grafting treatment showed outstanding root vigor;Zhen Liang 7388 cucumber was used as a scion,Ba Tu 613rootstock grafting treatment showed outstanding root vigor.It shows that grafting enhances the absorptive capacity of the root system and provides abundant water and mineral elements for the aboveground cucumbers.This experiment Ba Tu 613 is the most suitable rootstock for cucumber grafting.5.Changes in defensive enzyme activities in cucumber plants grafted on different rootstocks under soil salinization conditions.The results showed that with the growth of the plant,the activities of cucumber’s PAL,IAA oxidase,PPO,andβ-1,3-glucanase showed a trend of increasing first and then decreasing.The defensive enzyme activities of cucumber leaves were increased in the treatment of 4 kinds of rootstock grafting.Among them,Zhen Liang 7188cucumber was used as scion and Ba Tu 613 rootstock had the highest defense enzyme activity;Zhen Liang 7388 cucumber was used as scion,and Ba Tu 613 rootstock had the highest defense enzyme activity.It shows that the defense ability of cucumber plants can be improved by grafting,thereby improving the salt tolerance of cucumber.However,different rootstock combinations have certain differences in the improvement of cucumber salt tolerance.In this experiment,Ba Tu613 rootstock grafting is the most suitable.