Effects Of Exogenous Calcium And Calcium Inhibitors On Photosynthetic Characteristics Of Potato Under Low Light

Potato is an important food and vegetable type crop,Using the idle fields to planting potatoes in China’s jianghuai region in winter,not only can effectively improve the efficiency of the use of arable land resources,but also can increase farmers’income,and adjust the agricultural planting structure.the early growth of potato in the weak light stress easily lead to plant growth disorder,not only the inhibition of photosynthesis eventually reduced the yield and quality.Weak light stress usually leads to lodging for potato plants,resulting in yield reduction and quality decrease.So,it is important to study the mechanism of low light resistance of potato.In this study,two potato varieties（Red roses,sensitive to weak light;Kexin 1,insensitive to weak light）shading treatment(measured during the test greenhouse greenhouse no shading area.The natural light intensity is 270-350μmol·m^-2·s^-1,and the light intensity is 50-90μmol·m^-2·s^-1.Measured daily greenhouse temperature of26℃,the lowest temperature of 11℃,the processing time of 21 days.The results showed that the growth status,photosynthetic fluorescence characteristics,defensive enzyme activity,soluble protein content,chlorophyll content and chlorophyll fluorescence parameters of the two groups were compared with those of the control group and the treatment group.The main findings are as follows:1.Weak light stress can cause the morphological reconstruction of potato plants,so that the growth rate of plant height becomes larger and the increase of stem diameter is slowed down.Spraying exogenous CaCl₂ had little effect on the growth rate of potato plant height,but it could increase the crude stem and thicker.Exogenous CaCl₂ enhances the plant by reducing the plant height and plant height.In the case of low light conditions,the new varieties of potatoes with poor low light resistance were more slender than those of potato cultivars with strong light fastness.2.The net photosynthetic rate（P_N）of the two potato varieties was significantly decreased under low light stress,and the decrease of P_N was mainly affected by non-stomatal factors.Spraying exogenous CaCl₂ can effectively improve the net photosynthetic rate of potato plants under weak light stress,while spraying calcium inhibitor has the opposite effect.Under low light stress,the net photosynthetic rate of cultivars with low light tolerance was decreased.3.Under normal light,the POD,SOD and CAT activities of the two potato cultivars showed the trend of increasing first and then decreasing.The low light treatment significantly reduced the POD,SOD and CAT activities of the two potato cultivars.Spraying exogenous CaCl₂ could improve the antioxidant enzyme activity of potato plants under low light condition,and enhance the ability of plant to scavenge reactive oxygen species and improve the tolerance of plants to low light.4.The chlorophyll content of chlorophyll a and chlorophyll b decreased,and the exogenous CaCl₂ could increase the chlorophyll content of potato plants under normal light and low light.Under low light stress,the plant height of chlorophyll was increased by chlorophyll content,Increase the content of chlorophyll b to enhance the use of light energy.5.Weak light stress leads to a decrease in the PI_ABSBS value of the energy index based on the absorption of light energy,and the increase of the fluorescence intensity at point J.The addition of exogenous CaCl₂ can improve the PI_ABSBS value and decrease the J-point fluorescence intensity.Exogenous CaCl₂ may alleviate the stress of potato plants by increasing the response center activity of PSⅡand enhancing the electron transport.