Current Photosynthate as a Limiting Factor in Adventitious Root Formation on Leafy Pea Cuttings1

Root formation on leafy cuttings of Pisum sativum L. ‘Alaska’ was reduced by about 50% when net photosynthesis was adjusted to the compensation point by reducing the light intensity, reducing the CO 2 concentration, or by blocking CO 2 exchange with an antitranspirant. Rooting was also reduced by 50% when cuttings were given only enough photoperiod at saturating light to maintain a carbon balance similar to that of the treatments which reduced net photosynthesis to the compensation point. In addition to decreasing rooting, these treatments lowered sucrose and glucose levels in the basal portion of the cuttings compared to controls. Our photosynthesis and carbohydrate data indicate that the supply of current photosynthate to the base of pea cuttings is important to rooting.