The phenology of flowering in Spiranthes sinensis s.s.

Abstract

The native Spiranthes sinensis s.s. of Taiwan is an emerging ornamental potted orchid. This study aims to understand the conditions for floral differentiation and life cycle to facilitate artificial cultivation and commercial production of S. sinensis. Every August, new leaves appeared from the dwarf stem, during which the old roots acted as a nutrient source, providing the energy needed for the initial foliation phase. In November, the apical bud enters the floral initiation. In January, the apical bud began to transform into the primary inflorescence of the plant, while the lateral bud apical meristem began to differentiate into floral meristem. The plant produced a main spike in February, followed by the lateral bud inflorescences; the plant bloomed from March to May. Changes in sugar and starch contents were associated with inflorescence development. A higher soluble sugar level was noted in the roots and stems from January to April at the time of anthesis. Starch began to accumulate in the roots from February to August. The growth cycle restarted in August every year with new shoot formation, with the roots providing the initial nutrients for shoot growth to restart a new growing cycle. The influence of temperature changes on inflorescence development and flowering is discussed.