Analysis of correlation between in vitro growth of yam bulbil and starch synthesis

• 1、Agronomy School, Hebei Agricultural University, Baoding 071000, China

Abstract：To clarify the characteristics of bulbil development and the mechanism of starch accumulation in Dioscorea opposita Thunb., and to analyze the relationship between starch and bulbil development. In this paper, using Xiaobaizou Yam as material, we induced the formation of bulbil at different segments in vitro, observed the morphology and anatomical structure of bulbil at different developmental stages, and determined the content of starch in bulbil and related synthetase activities. It was found that the ways of inducing bulbil formation were different in lower segment (1-6 segment) and middle segment (6-9 segment), upper segment 10-12 segment (near middle segment) and upper segment 13-15 segment (near top segment). Bulbil length, adventitious root length and bulbil weight increased continuously during the whole growth period. The degree of cork formation increased gradually, the area of meristem area increased first and then decreased, the cell size in elongation area increased gradually, and the number and size of starch granules in mature area also increased gradually. The starch content accumulated steadily from the early stage of growth, and the activities of starch synthase (AGPase, GBSS, SSS, SBE, PGM) increased first and then decreased. There was significant positive correlation between bulbil length, adventitious root length and starch content. The result shows that the formation of bulbil induced by stem segments at different segments of yam was different. Starch is the main contributing factor to the growth and weight gain of granulation.

Keywords： Yam bubil Formation and development Organizational structure observation Starch content Enzyme activity