Seasonal variations in carbohydrate content of Carica papaya plants

Abstract

Monthly samples were collected of roots, stems, petioles and leaf blades of clonal female ‘Honey Gold’ papaw (Carica papaya L.) plants, in the cool subtropical Pietermaritzburg area, to study any seasonal variations in carbohydrate content of this tropical plant which grows continuously under favourable conditions. Under cool subtropical conditions, active leaf and stem growth ceased during autumn and winter, and there was a build up of sugars and starch at that time, in the petioles and stems in particular, and to a lesser extent in the roots. Most of the sugars were reducing sugars, especially in the leaf blade and petiole. The levels of starch attained were much lower than in deciduous fruit trees. Reducing sugar and starch levels dropped with the resumption of active growth during spring, summer and early autumn. Little accumulation would be expected under favourable tropical conditions.