(c) : In most of the plants, there is a sharp rise in respiration rate near the end of the development of fruit, which sets in progress those changes, which are involved in ripening of fruit. The ripening on demand can be induced in these fruits by exposing them to normal air containing about 1 ppm of ethylene. Suitable combination of gases in atmosphere for fruit ripening is 80% ethylene (C2H4) and 20% CO2