Effects of Temperature and Photoperiod on Assimilate Partitioning in Potato Plants

The effects of temperature and photoperiod on d. wt partitioning and 14C translocation were studied in three potato varieties. High temperatures and long days enhanced plant growth in terms of plant height and number of leaves, and also affected d. wt partitioning between the plant organs. However, no temperature effect was noted on total plant d. wt, nor on the export of 14C from the source leaf. Translocation of 14C to the vegetative organs (leaves and stems) was greater at higher temperatures, while translocation to the tubers was less under these conditions. We suggest that, under the temperature regimes studied, the main effect of high temperature is on assimilate partitioning and not on total plant productivity. Differences in response to high temperatures were observed among varieties, with Norchip showing the least and Up-to-Date showing the most sensitivity.