Effects Of Light On Growth And Development Of Strawberry In Greenhouse

Objective:Several serious issues need to be addressed regarding strawberry production in solar greenhouses in Xinjiang.These issues include late-marketing,low yields during the early production period,and disease problems.This objective of this study was to explore the effect of photoperiod and light intensity on strawberries grown.Specifically,the study examined the effects of photoperiod and light intensity on strawberry growth,fruit yield,and fruit quality.The results provide scientific and technical basis for strawberry production in solar greenhouse in deep winter.Methods:The strawberry cultivar in this experiment was‘Hongyan.’The experiment included four photoperiod treatments:8 hours of light（i.e.,short days）for 7,14,or 21d.The control was natural light.The experiment also included four light intensity treatments:natural light（control）50%shading,70%shading,and 90%shading.Results:The results were as follows:（1）The photoperiod treatments had significant effects on the vegetative growth of strawberry.The 7 d short-day treatment had no effect on vegetative growth.The 14 d short-day treatment promoted vegetative growth,and 21 d short-day treatment reduced vegetative growth.（2）The photoperiod treatments had significant effects on the photosynthetic characteristics and fluorescence characteristics of strawberry:The short-day treatments did not affect the net photosynthetic rate,stomatal conductance,transpiration rate,or intercellular CO₂concentration of strawberry;The 14-and 21-d short day treatments increased the maximum photochemical efficiency（F_v/F_m）and actual photochemical efficiency（Y（II））of the leaves to some extent.（3）The photoperiod treatments also significantly influenced the phenological periods of strawberry.The effects of the 7 d short-day treatment were not significant;however,the phenological periods were 5 to 7 d later in the 14 and 21 d short-day treatments（4）Strawberry yield was significantly affected by the photoperiod treatments.The 7 d short daylight treatment had no effect on yield.The 14 d short daylight treatment increased the number of fruit per plant and the yield per plant,but had no effect on the fruit weight.The 21 d short daylight treatment single fruit weight,The number of fruit per plant and the yield per plant were reduced.（5）The photosynthetic characteristics of strawberry were significantly affected by the different photoperiod treatments.The 7 d short daylight treatment had no effect on fruit quality.The 14 d short day treatment increased maximum single fruit weight and fruit shape index but decreased soluble sugar content.The 21 d short day treatment reduced maximum fruit weight,the fruit shape index,and the soluble sugar content.（6）Light intensity had significant effect on the photosynthetic characteristics and fluorescence characteristics of strawberry:The 50%shading treatment can increase the photosynthetic rate of the plants,increasing the light energy utilization rate of the plants,which is more conducive to plant growth,and the 70%and 90%shading treatments reduce the net photosynthetic rate of the plants;The shading treatments reduced initial fluorescence F_o and maximum fluorescence F_m,showing that the shading treatment protected the PS II reaction center.The maximum photosynthetic efficiency（F_v/F_m）and actual photochemical efficiency Y（II）of PS II in strawberry leaves were significantly greater in the 50%shading treatment than in the control.Thus,the 50%shading treatment favored the accumulation of photosynthetic products.（7）Light intensity had significant effect on the vegetative growth of strawberry.The50%shading treatment promoted vegetative growth whereas the 70 and 90%shading treatmentd weakened plant growth potential.Plant growth decreased as shading increased.（8）Light intensity treatment had a significant effect on the late strawberry fruit.The 50,70,and 90%shading treatments delayed the 3 to 5 d of strawberry fruit and shortened the flowering period by 2 to 3 d.（9）Strawberry yield was also significantly affected by light intensity treatment.The 50%shading treatment increased single fruit weight and yield per plant,but had no effect on the number of fruit per plant.The 70%shading treatment reduced the yield per plant and fruit weight,but had no effect on the number of fruit per plant.The 90%shading treatment reduced single fruit weight,the number of fruit per plant,and the yield per plant.（10）Light intensity significant affected strawberry fruit quality.The shading treatment had no effect on fruit color or fruit shape.The 50%shading treatment increase maximum single fruit weight.The 70%shading treatment reduced maximum single fruit weight and the fruit shape index.The 90%shading treatment reduced maximum single fruit weight,the fruit shape index,and the soluble sugar content.Conclusion:The 7 d short day treatment had no effect on vegetative growth,late growth,yield,or fruit quality.The 14 d treatment reduced Plant growth and development,growth period 5-7 days ahead,single fruit weight,fruit number per plant,yield and soluble sugar content.The 50%shading treatment promoted vegetative growth.The maximum photosynthetic efficiency（F_v/F_m）and actual photochemical efficiency Y（II）of PS II in strawberry leaves were significantly higher in the 50%shading treatment than that of the control treatment,which was conducive to the accumulation of photosynthate in plants.The 50%shading treatment delayed flowering by 2 to 3 days,shortened the flowering period by 2 to 3 days,and increased single fruit weight and yield per plant.The 50%shading treatment had no effect on the number of fruit per plant.The 70 and 90%shading treatments reduced plant growth Possibility,reduction of plant yield,single fruit weight,and yield per plant by3-5 days late in delay.