LIGHT, DARK AND GROWTH-REGULATOR INVOLVEMENT IN GROUNDNUT (ARACHIS-HYPOGAEA L) POD DEVELOPMENT

Gynophore elongation and pod formation were studied in peanut plants ( Arachis hypogaea L.) under light and dark conditions in vivo. The gyno phores elongated until pod formation was initiated. Pod (3-20 mm lengt h) development could be totally controlled by alternating dark (switch ed on) and light (switched off) conditions, repeatedly. Gynophore elon gation responded conversely to light/dark conditions, compared to pods . In this study we aimed to correlate the light/dark effects with endo genous growth substances. The levels of endogenous growth substances w ere determined in the different stags of pod development. Gynophores s hortly after penetration into the soil, 'white' gynophores, released t wice the amount of ethylene as compared to the aerial green ones, or t o gynophores bearing pods. Ethylene inhibitors had no effect on the pe rcent of gynophores that developed pods, but affected pod size which w ere smaller compared to the control. A similar level of IAA was extrac ted from gynophore tips of green gynophores, 'white' gynophores and po ds. ABA levels differed between the three stages and were highest in t he green gynophores and lowest in the pods.