實驗花的構造ppt課件(編輯修改稿)
2025-05-30 22:07 本頁面
【文章內容簡介】 An intact flower. In some flowers, such as lilies, the sepals and petals are similar to one another, and the perianth parts may then be referred to as tepals. Note that the sepals are attached to the receptacle below the petals. (b) A partly dissected flower with two tepals and two stamens removed to reveal the ovary. The gynoecium consists of the ovary, style, and stigma. The stamen consists of the filament and anther. Note that the sepals, petals, and stamens are attached to the receptacle below the ovary, which is made up, in the lily flower, of three fused carpels. Such a flower is said to be hypogynous. The wall of the pollen grain serves to protect the male gametophyte on its often lIozardous journey between the anther and the stigma. The outer layer, or exine, is posed chiefly of a substance known ossporopollenin, which appears to be a polymer posed chiefly of carotenoids. The exine, which is remarkably tough atld resistant, is often elaborately ~culptured. The sculpturing of pollen grain walls is very precise and distinctly different from one species to another, as revealed ill these scanning electron micrographs of pollen g
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