The influence of light quality on peanut (Arachis Hypogaea L.) gynophore pod and embryo development in vitro

The stimulation of gynophore elongation and the inhibition of pod ovule and embryo development in vitro were found to be irradiance dependent. The response was induced by irradiation fluency above threshold levels and varied according to spectral quality. White (W) and red (R) radiation acted similarly on the stimulation of gynophore elongation and pod inhibition, while blue (B) radiation resembled W and R at the high photon flux densities. At lower flux densities, B radiation effects on gynophore elongation and pod formation resembled those of Far-Red (FR) radiation. The latter was least effective in stimulating elongation and most effective in inducing pod development. The process of pod formation was more sensitive than gynophore elongation to flux densities greater than threshold levels. FR reversed R radiation effects on both gynophore elongation and pod development, suggesting the involvement of phytochrome. Embryos isolated from ovules and cultured in vitro resumed growth and developed into seedlings under all spectral treatments. For flux densities greater than threshold levels the growth of exposed embryos remaining inside halved ovules was reduced compared to completely isolated ones. The role of the ovular tissue in radiation perception and the regulation of peanut embryo growth is discussed.