Effects Of Different CaCl₂ Combinations On The Germination And Seedling Growth Of Summer Squash Under Low Temperature And Low Light

In this study,low temperature sensitive Summer squash seeds were used as experimental materials.The effects of fulvic acid,HIDS-K acid and CaCl₂ on Seed Germination and seedling growth of Summer squash under low temperature and low light were studied.The main conclusions obtained are as follows:1.Seed soaking treatment of CaCl₂ and mixed solutions of CaCl₂ with HIDS-K and CaCl₂ with FA can alleviate the germination of Summer squash seeds under low temperature stress.The germination rate,germination potential,germination index and vigor index all increase in varying degrees,and promote the growth of root system.It can also reduce the peroxide content in Summer squash sprouts under low temperature stress and improve osmotic regulation Substance content and antioxidant enzyme activity.2.Foliar spraying of CaCl₂ and mixed solutions of CaCl₂ with HIDS-K and CaCl₂ with FA have a positive effect on reducing the peroxide content and increasing the activity of antioxidant enzymes in seedlings.It can improve the activity of superoxide dismutase（SOD）,peroxidase（POD）and catalase（CAT）in Summer squash seedling leaves,and reduce the content of MDA and peroxide.3.Foliar spraying of CaCl₂ and mixed solutions of CaCl₂ with HIDS-K and CaCl₂ with FA can increase the content of soluble sugar,soluble protein and proline in the leaves of Summer squash seedlings to a certain extent,and improve plant penetration regulation ability.4.After spraying of CaCl₂ and mixed solutions of CaCl₂ with HIDS-K and CaCl₂ with FA,the photosynthetic rate Pn,transpiration rate Tr,and stomatal conductance Gs of Summer squash seedlings were significantly higher than The intercellular.The CO2 concentration Ci was significantly lower than that of CK.There are varying degrees of improvement in photosynthesis.5.Fv’/Fm’,Fv/Fm,ΦPSII,ETR,and q P of Summer squash seedlings were significantly higher than those of CK after spraying a compound solution of calcium chloride and CaCl₂ and mixed solutions of CaCl₂ with HIDS-K and CaCl₂ with FA,Chlorophyll fluorescence parameters have been improved to varying degrees,which has a certain protective effect on the PSII response center.