Endogenous reserves of carbohydrates, protein and phenol influences dormancy and sprouting of bulbs of tuberose

Abstract

The changes in the endogenous reserves of carbohydrates, protein, and phenol in bulbs of Polianthes tuberosa L. were determined in the four stages of development viz. bulb harvesting, dormancy, sprouting and initial plant development to understand the influences on dormancy and sprouting of bulbs in two genotypes Calcutta Single and Calcutta Double. The results depicted a gradual increase in reducing sugar from bulb harvesting (1.88 mg/g) to dormancy (2.09 mg/g) to sprouting (2.50 mg/g) and peak at initial plant development (3.60 mg/g). The non-reducing sugar showed a sharp climb from dormancy (2.28 mg/g) to sprouting (2.78 mg/g) but dropped during the initial plant development (2.51 mg/g). The starch accumulation sharply declined from harvesting (6.94 mg/g) to dormancy (3.28 mg/g) but increased during initial plant development. The protein declined from dormancy (1.76 mg/g) to sprouting (0.35 mg/g) and increased during initial plant development (1.99 mg/g). The phenol peaked during dormancy (2.68 mg/g) but a decline in sprouting (2.04 mg/g). The nonreducing sugar was observed to be significantly correlated to reducing sugar in Calcutta Single and Calcutta Double. The changes in the endogenous reserves enforced the bulbs to enter dormancy thereafter facilitating overcoming dormancy and promoting initial growth.