THE EFFECT OF PHOTON FLUX-DENSITY AND DURATION OF THE PHOTOSYNTHETIC PERIOD ON GROWTH AND DRY-MATTER DISTRIBUTION IN CARROT

The distribution of dry matter between shoot and storage root of carrot plants grown in light regimes varying in intensity, duration and integral, is used to test an hypothesis for the control of assimilate partition Results from seven varieties show that shoot to storage root weight ratios are affected by the light environment, but that these effects are associated with the effect of light on plant size It is concluded that quantitative alterations to the supply of assimilate, resulting from variation in the light regime, do not affect its partition to different organs This is discussed in relation to other investigations which have suggested a relationship between the duration of the photosynthetic period, assimilate sequestration in foliar starch and partition between shoot and root. © 1990 Annals of Botany Company.