溫度處理對熱帶花椰菜莖頂端分生組織發育之影響

Effect of Temperature Treatments on the Development of Shoot Apical Meristem in Tropical Cauliflower

藉由觀察花椰菜莖頂端分生組織，以及春化基因BoVRN2與開花抑制基因BoFLC1和BoFLC2的表現，以了解溫度對熱帶花椰菜苗期的影響。結果顯示，溫度、自交系及其交感作用間均顯著影響莖頂端分生組織的發育。在18處理中，‘Winner’的莖頂端生長顯著較佳經由BoVRN2、BoFLC1與BoFLC2的調控加速花球的發育。‘Winner’在22處理的花球發育成長僅次於18處理，BoFLC1量的降低促使莖頂端分生組織形成花球。在26中與30中，‘Winner’的BoFLC1量微幅波動或後續調升使莖頂端分生組織的生長較為緩慢雖然‘Winner’屬於耐熱早生型的花椰菜但在苗期因高溫的影響亦會延緩其生長。‘PI244664’在22、26與30處理中BoFLC1與BoFLC2量皆顯著增加明顯抑制中晚生型花椰菜的結球發育。本研究結果有助於了解溫度對熱帶花椰菜結球表現的影響，對於不同類型花椰菜在栽培或季節條件的選定上提供新的資訊。

This study investigated the effects of different temperature treatments (18, 22, 26, and 30 °C) on apex development in tropical cauliflower of various maturity types. Two inbred lines ‘Winner’ (early maturity) and ‘PI244664’ (mid–late maturity) were used as the experimental materials. Analysis of variance revealed significant effects regarding main temperature and cultivar as well as their interaction. The inbred line ‘Winner’ showed the best apex elongation and diameter growth at 18 °C followed by 22 °C. By observing tissue dissection, the apex of 'PI244664' begins to form two small inflorescences at 18 °C. Gene expression of indicated BoVRN2, BoFLC1 and BoFLC2 were down-regulated and then led ‘Winner’ towards curding at 18 °C. In temperature 22 °C treatment, the apex growth was slightly delayed in ‘Winner’. The BoVRN2 expression pattern showed at 22 °C condition was similar to those at high temperature 26°C and 30°C environments. Gene expression results suggested that BoFLC1 performed non-vernalized pathway at 22°C. Apex and leaf growth also revealed the coexistence of vegetative and reproductive growth at 22 °C. The expression of BoFLC1 level showed slightly decrease in 'Winner' at 26 °C and 30 °C. High temperature significantly delayed seedling growth including apex and phenotype. The expression of BoFLC1 and BoFLC2 in 'PI244664' were significantly increased at 22 -30 ° C and these temperatures inhibited the curd development.