薄壳山核桃雌雄花芽分化外部形态与内部结构的关系

【目的】 观察薄壳山核桃品种‘Pawnee'(雄先型)的雌雄花花芽分化,了解控花控果的花期调控关键过程。【方法】以该品种为试材,通过物候学定期观察,结合石蜡切片技术、番红固绿对染,对其花芽外部形态变化和解剖结构进行研究。【结果】薄壳山核桃‘Pawnee'雄花芽4月上旬次第进入雄花序分化期、雄花原基分化期、花萼原基分化期、雄蕊原基分化期、花药分化期、花粉囊和花粉粒形成期; 与之对应的形态变化表现为雄花芽嫩绿柔软褐变雄花芽膨大雄花芽鳞片开裂雄花序伸长小花膨大苞片开裂花药变黄色。雌花芽顶生混合芽的分化从4月中旬进入形态分化临界期后,历经雌花花序分化期、花柄原基和雌花原基分化期、花被原基分化期、苞片原基分化期、花萼原基分化期、雌蕊原基分化期和胚珠分化期。与之对应的形态变化表现为:雌花芽鳞片黄绿色变至褐色雌花芽褐色变成灰绿色鳞片逐渐张开鳞片脱落幼叶展开小花原始体出现和膨大露出柱头花柱伸长。【结论】雌雄花芽外部形态直观反映内部结构变化,可方便快捷地判断薄壳山核桃雌雄花芽分化时期。

Observation of morphological and anatomical characters on staminate and pistillate flower differentiation in Carya illinoensis (Wangenh.) C. Koch

[Objective] The demand for the pecan cultivar 'Pawnee' (pro) is high in China. However, its heterodicog-amous often cases unstable yield. Studying the process of flower differentiation is essential for the adjustment of the flow-ering period and balance year' s production. [ Method] We combined phonological observation with photographs of paraffin sections to study the developmental progress during flower differentiation; we observed ' Pawnee' 's ( protan-drous) fruiting bud differentiation and the growth of female and male gametophytes. [ Result] We established a connection between external morphology and internal anatomy during development. Male pecan flower budding initiates in early April; this is then followed by the inflorescence differentiation stage, stamen differentiation stage, sepal primordium differentiation stage, stamen growth stage, anther develop stage, and pollen sac and pollen formation stage. The corresponding morphological changes included: male flower buds changed from green and soft to brown and hard, the buds swelled, male flower bud scales cracked, inflorescence elongated, flower bracts swelled and cracking, then an-ther turn to yellow. The female flower buds began to develop from a terminal branch since mid-April. They then entered the critical period of morphological differentiation as follows: pistillate inflorescence differentiation stage, flower stalk and flower primordium differentiation phase, perianth primordium stage, bract primordium differentiation phase, sepal differentiation stage, pistil differentiation stage, and ovule differentiation stage. The corresponding morphological changes included: female flower bud scales changed from yellow green to brown to gray green, the scales gradually opened, flake off epidermis, floret primordium appeared swollen, exposing the stigma and style of elongation. Thus, it is feasible to judge the period of pecan flower differentiation based on flower buds' morphology and anatomical structure preliminary.