Muskmelon variety of 'Cuitian' was used as material,by sand culture experiment of modified Hoagland nutrient solution formula,six nitrogen levels(0,5,10,15,20,25 mmol·L~(-1))were conducted to study the effects of different nitrogen levels on growth and photosynthetic characteristics in the greenhouse on the tropic region.The results showed that the number of notes,maximum width of blade,maximum length of blade,stem diameter,number of leaves,fruit length,fruit width,seed chamber width,fruit flesh thickness,f...