Articles
POTENTIAL FRUIT GROWTH OF TOMATO AFTER LIMITING ASSIMILATE SUPPLY
Sub-potentially growing fruits were subjected to a sudden change from limiting to nonlimiting assimilate supply, and growth was compared with fruits growing potentially from anthesis onwards.
After transition from source- to sink-limited conditions it took two to three weeks before fruit growth rate was as fast as that from fruits grown potentially from anthesis.
Apparently, the fruit can not adapt its growth rate immediately to a surplus of assimilates.
A physiological explanation of the delay is that the fruit’s capacity to process assimilates may be adapted to its previous assimilate availability and that time is needed to adjust it to a significant increase in assimilate supply.
A model is presented that describes the observed adaptation rate.
Further, a conceptual mechanism is proposed that distinguishes two components of sink activity: the amount of assimilate processing machinery and the specific activity.
On the basis of this mechanism the response of sink activity to assimilate availability and temperature is discussed.