Jl. John et al., THE INFLUENCE OF PLANT-GROWTH REGULATORS AND LIGHT ON MICROTUBER INDUCTION AND FORMATION IN DIOSCOREA-ALATA L CULTURES, Plant cell, tissue and organ culture, 34(3), 1993, pp. 245-252
The effects of plant growth regulators, light intensity, and end-of-da
y (EOD) light quality treatments on node and microtuber induction (% o
f cultures with microtubers) and development (fresh weight of microtub
ers) in yam (Dioscorea alata L. cv. Oriental) cultures were investigat
ed. Nodal segments were excised from plantlets cultured on tuberizatio
n medium containing growth regulators and exposed to various light tre
atments. Abciscic acid (1 muM) stimulated and cytokinins (2.5 muM) inh
ibited microtuber development from yam nodal segments cultured on Mant
ell's and Hugo's full-strength tuberization medium under 8-h photoperi
ods. EOD far-red (FR) light inhibited microtuber induction and develop
ment and enhanced node formation. EOD FR light effects were nullified
by immediately following the FR treatment with red light. This suggest
ed the involvement of phytochrome in these processes. The lowest light
intensity evaluated (12 mumol m-2 s-1) inhibited microtuber, root and
shoot production as compared to light intensities of 42, 72 and 102 m
umol m-2 s-1. Kinetin (2.5 mum) in half-strength tuberization medium i
nhibited microtuber induction and development but did not affect node
production in the light intensity evaluation.