Nutrio-physiological studies on the tomato plant II. Translocation of photosynthates

The percentage translocation from the leaf is low in the tomato; it is as low as 16 per cent in some cases and the maximum value observed is 62 per cent.

The ability of a leaf to act as the sink for the photosynthates of other leaves becomes very low with age, but it serves as a sink for its own photosynthates for a long period.

The photosynthates of a leaf may be translocated to any alnk, but the major translocation stream under ordinary conditions is determined by the growth stage of the plant and the position of the source leaf. In this sense thero are source-sink partnerships between certain leaves and organs: The major sinks of L₅, L₉, L₁₁, L₁₄, and L₁₆ are the roots, T-1, T-Il, T-III, and T-III, respectively, although the partnerships are weak and flexible.