Effects of Foliar Spraying 5-Aminolevulinic Acid on Growth, Photosynthesis and Yield of Tomato under Shade Conditions

To make clear the influence of 5-aminolevulinic acid(ALA) on the growth and development of tomato under weak light,the plant height,stem diameter,photosynthesis characteristics,chlorophyll content and yield of tomato were investigated after sprayed 0.06 g/m2 ALA.The results showed that the stem diameter,net photosynthetic rate(Pn),stomatal conductance(Gs),carboxylation efficiency(CE),apparent quantum yield(AQY),the light compensation point(LCP) and yield of tomato were decreased by shading treatment.On the contrary,the intercellular CO2 concentration(Ci) and CO2 compensation point(CCP),chlorophyll content and plant height of tomato increased.Compared with spraying water,the decrease range of Pn,Gs,CE,AQY,LCP and yield and the increase range of Ci and CCP were relatively smaller after sprayed ALA under shade conditions,while the chlorophyll content increased.The foliar application of ALA had little influence on the tomato growth,photosynthesis characteristics and yield in 80% shade condition.In conclusion,it was benefit to the photosynthesis and yield of tomato under weak light by foliar spraying 0.06 g/m2 ALA.