Three alternative mechanisms leading to seasonal variations in bunch and total dry matter production commonly found in stands of oil palm, were examined using a simulation model. The alternatives were: (i) the use of a store of reserve assimilate to accommodate both shortfalls and excesses in current assimilate production, (ii) variation in response to sink demand in the light-saturated rate of gross photosynthesis (AMAX), and (iii) variation in the proportion of gross assimilates consumed in dark respiration (%R). The alternatives were tested using data from three palm populations for one of which, trunk carbohydrate concentrations had also been measured.

The results show that with certain assumptions, any of these processes could account for the seasonal variations in productivity recorded. However, certain periods of relatively high or low productivity required extreme variations in AMAX, which were considered unlikely. The variations in %R which were needed were also thought unlikely as periods of high productivity required %R to decrease, whereas the opposite trend was more probable. Thus, of the three processes, the utilization of storage reserves appeared the most likely means of accommodating variations in sink demand. However, a model based solely on use of assimilate storage was not entirely consistent with measured changes in trunk reserves and changes in AMAX and / or use of reserves, located in other parts of the palm may be involved.

Further research needed to resolve this issue is suggested.