文心蘭'Gower Ramsey'假球莖與花序之生長、形態與解剖

Growth, Morpholgy and Anatomy of Pseudobulb and Inflorescence in Oncidium 'Gower Ramsey'

本研究主探討文心蘭'Gower Ramsey'之成熟植株，在台北威諾型溫室下、自新芽萌發、發育期、出鞘期及假球莖成熟與花序發育之生長週期。結果一年內可得二生長週期得兩次切花。解剖觀察，營養芽萌發時已具13～14節，第0到1節間肥大成假球莖。假球莖基部有明顯5個潛伏芽，第0至1節的潛伙芽為花梗芽，其下-2到-4節上之潛伏芽為營養芽。假球莖長0.4～2.1cm時細胞分裂旺盛，花便芽在出鞘期隨假球莖之伸長而分化，到剛長好的假球莖，其花梗長4.3cm，已具有23節，於第17節位左右分化花朵，其下為側枝，儼然已分化出幼嫩花序，之後花梗的伸長，主要是花序側枝的分化與發育，花序主軸頂端也緩隆分化些許花朵。故推論出鞘期是決定能否抽出花序之關鍵期。

The growth, morphology and anatomy of pseudobulb and inflorescence were studied in Oncidium 'Gamer Ramsey' grown in Venlo glasshouse conditions. Mature plants could complete two growth cycles, with one cycle comprised from bud, plantlet, unsheathing to pseudobulb stage. Therefore the cut flowers could be harvested twice in one year. Anatomical observation revealed that a newly elongated vegetative bud contained 13~14 nodes, where the nodes 0~1 were enlarged to form the pseudobulbs. The psendobulb base was observed to contain five latent buds, with a flower stalk developed from the nodes 0-1 (numbered 0-1 basipetally from the pseudobulb base) and vegetative bulbs from the nodes -2~5. Active cell division was seen when the length of the pseudobulb was 0.4~2.1cm. Pseudobulb formation occurred during the unsheathing stage and flower stalk was differentiated when pseudobulb elongating. The length of flower stalk was 4.3cm when the pseudobulb was fully developed. This young inflorescence contained 23 nodes, with floral promordia initiated on the node numbered 17 und above. Differentiation and development of inflorescence branches occurred rapidly during the period of flower stalk elongation, while differentiation of new floral bud on the main inflorescence apex was slow. Results suggested that the unsheathing stage was the critical stage to determine the plants' flowering.