黄瓜去顶苗直接成花的形态学研究

本文对黄瓜0—7天幼苗及去顶后0—8天诱导花芽分化苗与诱导营养芽分化苗的子叶节进行了系统石蜡切片观察,未发现0—7天幼苗的子叶叶腋存在潜伏芽。去顶后1—2天在子叶叶柄基部与切口之间的表皮下细胞分裂形成突起,去顶后6天诱花苗与诱芽苗的突起表现出形态差异,诱花苗突起的上端变钝,而诱芽苗突起的上端成尖锥状。去顶后8天诱花苗在子叶叶柄与切口之间形成完整的花芽。另发现有少量花芽起源于切口处细胞。对去顶后0—6天诱花苗与诱芽苗的子叶节还进行了电镜扫描观察,观察结果与石蜡切片基本一致。

MORPHOLOGICAL STUDIES OF DIRECT FLOWER FORMATION OF THE DECAPITATED CUCUMBER SEEDLINGS

The morphological changes in the co-tyledonary nodes of cucumber seedlings cultured on inducing floral bud medium (IFBM), and on inducing vegetative bud medium (IVBM), were studied during 0 to 7 days before decapitation and during 0 to 8 days after decapitation with light microscopy. No latent bud was observed at the cotyledonary axils of 7-day-old seedlings. The first day after decapitation, epidermal and/or subepidermal cells between cut and base of cotyledonany petiole started to divide. The second day after decapitation, these dividing cells resulted in globular protuberances. To the 6 th day after decapitation, there appear the appa- rent differentiation between protuberances in seedlings in IFBM and in IVBM, and thc former top become blunt and the latter top become tip. In addition, we observed the rare floral bud formation in cut region on the 6 th day after decapitation. On the 8 th day after decapitation, floral buds with sepal, petal, stamen primordia between cut and base of cotyledonary petiole formed in seedling in IFBM. The morphological changes in the cotyledonary nodes were studied during 0 to 6 days after decapitation with scanning microscopy as well. The observed results were basically consistant with that of light microscopy.