Periodicity of inflorescence initiation and development in Nerine bowdenii W. Watson (Amaryllidaceae).
1994
Theron K.I. | Jacobs G.
Nerine bowdenii bulbs were sampled from a commercial planting and dissected at 2-week intervals from 9 Oct. 1990 to 12 Nov. 1991. The following variables were recorded: number of florets per inflorescence, differentiation stage of the oldest floret, exterior dimensions of the inflorescence, and the number of leaf primordia between the two innermost inflorescences and between the innermost inflorescence and the vegetative apex. Scanning electron micrographs were made of the inflorescences at different stages of development. The development of the inflorescences of the growth units appeared to be synchronized. When the florets of the outermost inflorescence reached stage Late G (gynoecium elongated, carpels fused), the spathe started to elongate. When florets in the second inflorescence reached stage Mid G (three carpels elongated, not fused), the innermost inflorescence was initiated. Inflorescence development passed through three phases: 1) a floret initiation phase of approximately 1 year, when nine to ten florets were initiated, 2) a differentiation phase, also approximately 1 year long when individual florets developed up to stage Late G, and 3) an inflorescence enlargement phase, which lasted approximately 4 months and culminated in anthesis. Leaf primordia were initiated at the same rate as florets (one per month) and the vegetative phase for a growth unit was completed within 1 year.
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