Light Intensity-Induced Morphogenetic Response and Enhanced β-Sitosterol Accumulation in Date Palm (Phoenix dactylifera L. cv. Hayani) Callus Culture

The present study, for the first time, assessed the influence of light intensity on morphogenesis of callus cultures and accumulation of beta-sitosterol, a key phytosterol compound in date palm. High frequencies of calli with maximum biomass were induced from shoot tip explants in Murashige and Skoog basal medium supplemented with 10 mg/l 2,4 dichlorophenoxyacetic acid + 3 mg/l 2-isopentyladenine. Such proliferating callus cultures of date palm cv. Hayani were incubated in specified medium under different light intensities [0, 14, and 42 mu mol/m(2)/s photosynthetic photon flux density (PPFD)]. The collected data exhibited an increase in callus volume, globularization, newly differentiated somatic embryos, degree of browning, and beta-sitosterol contents of callus cultures. Various effects of different light intensities on the above-mentioned traits were recorded. Morphogenesis of callus under dark condition (0 mu mol/m(2)/s PPFD) resulted in a higher degree of globularization and produced maximum number of newly differentiated somatic embryos. Whereas, under gradually increasing light intensities (14 and 42 mu mol/m(2)/s PPFD), a surge in the accumulation of beta-sitosterol content in the proliferating callus was observed. Thus, from the present study, it can be deduced that a proper application of suitable light intensity on proliferating callus has beneficial influence on morphogenesis and a higher production of beta-sitosterol in date palm.