Difference in Diurnal Variations of Primary Photochemical Reactions in Maize Leaves Grown in Different Directions Responses of primary photochemical reactions in apple fruit peel to the changes of incident PFD and air temperature in sunny days Detection of photosynthetic effective radiation (PAR) in tree canopy by Reinecke salt actinometer Chemical Changes Caused by LED Lamps in Nutrient Solution and Its Effect on Plant Growth