Regulation of the Movement of Assimilate Into Ovules of Pisum sativum Cv. Greenfeast: Effect of Pod Temperature

Abstract

Studies of ¹⁴C distribution in P. sativum cv. Greenfeast over 24 h indicate that 60-80% of ¹⁴C incorporated by the single leaf, on a plant pruned to leave one leaf and one pod, moves to the growing ovules at all developmental stages. Approximately 40% of the total activity was found in the ovules within 5 h after exposure of the leaf to ¹⁴CO₂. As the pod temperature increases there is an increase in ¹⁴C uptake by the ovules, from 2% of the total ¹⁴C assimilated by the leaf at 10°C to 28% at 30°C, within 2.5 h of ¹⁴C application. These results are discussed in relation to possible mechanisms of nutrient uptake by the pod. However, it is impossible at this stage to decide whether the transport of photosynthate into the developing fruit and its seeds is controlled simply by the metabolic sink status of the developing system or if, in addition, there is a 'remote' effect on the transport system itself.