Heating bearing shoots near fruits promotes sugar accumulation in melon fruit

Shoots near fruits of Cucumis melo L. were continuously heated at night to a minimum of 30 °C from the fifth day after anthesis (DAA). Minimum and maximum ambient temperatures in the heating apparatus were about 24 and 37 °C, respectively, and these temperatures were 13 and 7 °C higher, respectively, than the minimum and maximum control ambient temperatures in the greenhouse. Minimum and maximum temperatures of fruit near heated shoots (designated heated fruit) were 15 and 28 °C; these temperatures were 3 and 2 °C higher, respectively, than those of control fruit. Flesh temperature of the heated fruit measured by thermograph was also much higher than that of the control fruit. Heated fruit weighed significantly less than control fruit. Cell size of heated fruit was smaller than that of control fruit. Sucrose phosphate synthase (SPS) activity and mean sucrose content were higher in heated fruit than in control fruit.

► Shoots near melon fruits were continuously heated from 5 day after anthesis to a minimum of 30 °C during night.
► Fruit weight of the heated fruit was significantly smaller than that of the control fruit.
► Cell size of the heated fruit was smaller than that of control fruit.
► Sucrose phosphate synthase activity of the heated fruit was higher than that of control fruit.
► Mean sucrose content of the heated fruit was higher than that of the control.