The influence of light, gibberellic acid and CCC on sprout growth and mobilization of tuber reserves in the potato (Solanum tuberosum L.).

'Warm white' fluorescent light inhibited the elongation of potato sprouts and reduced the rate at which reserve materials in the mother tuber were mobilized. The evidence indicated that the influence of light on mobilization was independent of light effects on the magnitude of the 'sink' for translocates in the sprout. However, dark-grown sprouts exerted a greater directive influence than illuminated sprouts on the translocation of the mobilized materials.The rate of elongation and increase in dry weight of sprouts was promoted by exogenous GA independently of the effects of light on these processes, and the absence of any effects of CCC on sprout length and dry weight in these experiments was interpreted to indicate that light did not influence these parameters by controlling the level of endogenous gibberellins. Neither GA nor CCC modified the effects of light on the dry matter content of the sprouts, suggesting that growth in darkness and growth induced by GA were qualitatively different. The results are compared with the effects of light and GA on growth and stem elongation in other species.