To protect themselves from drying out, plants and trees drop their buds, blooms and leaves. For cut flowers and potted plants this dropping is often the result of over-production of the growth hormone ethylene; the only known gaseous, naturally occurring plant growth hormone. Ethylene gas regulates the ripening/ageing of cut flowers, potted plants, fruits and vegetable fruits. Ethylene gas is therefore purposely used to promote the ripening of fruit and the blooming of potted plants.
Fruits like tomatoes, bananas and apples produce high levels of ethylene. This gas will influence the ethylene production in the plant and by this cause more rapid ageing of flowers and leaves. Some ethylene sensitive plants will even show bud, flower and/or leaf drop.