Effects of Organic Nutrients and Hormones on Growth and Development of Tissue Explants from Coconut (<i>Cocos nucifera</i>) and Date (<i>Phoenix dactylifera</i>) Palms Cultured <i>in vitro</i>

Abstract

Abstract The growth response (increase in weight) of cultured explants from seedling date ( Phoenix dactylifera L.) and mature coconut ( Cocos nucifera L. cv. Malayan Dwarf) palms to source and concentration of organic nitrogen. carbohydrate, auxins, cytokinins and gibberellins was examined. Growth was strongly stimulated by the presence of auxins (10 −7 to 10 −6 M ), cytokinins (10 −6 to 10 −5 M ), high concentrations of sucrose (0.2 M ), and in the absence of NH 4 Cl, by organic sources of reduced nitrogen. Higher concentrations of auxin (2,4‐D or NAA at 10 −6 to 10 −5 M ) which still stimulated growth of Phoenix tissue, proved inhibitory to growth of freshly excised Cocos tissues. Explants from both palms initiated roots when subcultured on a medium with increased levels of auxin (NAA, 2.5 × 10 −6 to 2.5 × 10 −5 M ) and reduced levels of cytokinin (6‐BAP, 5 × 10 −8 M ). Isolated roots excised from these explants continued growth and produced new laterals when subcultured on media with GA 3 (5 × 10 −7 M ) and reduced levels of auxin, cytokinin, and either minerals or sucrose.