糖蜜草（Melinis minutiflora Beauv．）幼穗分化发育．及花和果实形态的研究

本文对糖密草（ＭｅｌｉｎｉｓｍｉｎｕｔｉｆｌｏｒａＢｅａｕｖ．）的幼穗分化发育及花和果实的形态作了研究，将幼穗分化发育过程划分为以下九个时期：第一苞原基形成期；第一次枝梗原基形成期；第二、三次枝梗原基形成期；小穗及颖花原基形成期；雌、雄蕊原基形成期；花粉母细胞形成期；花粉母细胞减数分裂期；花粉充实期；花粉成熟期。全过程历时约需４２ｄ．从抽穗到颖果成熟约需５０ｄ。糖蜜草的花序为圆锥花序。每花序有可育花２０００—３０００朵．小穗是由小穗轴、内外颖片、不育花外稃和小花构成。小花包括有内外稃各一片、一鳞被、雄蕊三枚和一枚雌蕊，颖果千粒重为９１ｍｇ。

STUDIES ON DIFFERENTIATION AND DEVELOPMENT OF YOUNG SPIKE AND MORPHOLOGY OF FLOWER AND FRUIT OF MELINIS MINUTIFLORA BEAUV

The studies on process of differentiation and development of young spike and on morphology of flower and fruit of Melinis minutiflora Beauv. reveal that the process can be divided into nine stages, namely: 1. The stage of first bract primordium formation F 2. The stage of primary branch primordium formation; 3. The stage of secondary and third branches primordia formation ; 4. The stase of spikelet and floret primordia formation ; 5. The stage of stamen and pistil primordia formation ; 6. The stage of pollen mother cell formation ; 7. The stage of meiosis of Pollen mother cell ; 8. The stage of pollen filling; 9. The stage of Pollen maturation. The duration of the process is about 42 days, and the duration from heading to caryopsis maturation takes about 50 days.The inflorescence is a terminal panicle with 2 000-3 000 fertile florets. Each spikelet consists of an outer glume, an inner glume, a lemma of sterile floret and a fertile floret on their rachilla. Each fertile floret includes a lemma, a pelea, a lodicule, three stamens and a pistil. The weight of thousand grains of caryopsis is 91mg.