|
Gynoecium (from Ancient Greek , ''gyne'', meaning ''woman'', and , ''oikos'', meaning ''house'') is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of (one or more) pistils in a flower and is typically surrounded by the pollen-producing reproductive organs, the stamens, collectively called the androecium. The gynoecium is often referred to as the "female" portion of the flower, although rather than directly producing female gametes (i.e. egg cells), the gynoecium produces megaspores, each of which develops into a female gametophyte which then produces egg cells. The term gynoecium is also used by botanists to refer to a cluster of archegonia and any associated modified leaves or stems present on a gametophyte shoot in mosses, liverworts and hornworts. Flowers that bear a gynoecium but no androecium are called carpellate. Flowers lacking a gynoecium are called staminate. The gynoecium is often referred to as female because it gives rise to female (egg-producing) gametophytes, however, strictly speaking sporophytes do not have sex, only gametophytes do.〔 Gynoecium development and arrangement is important in systematic research and identification of angiosperms, but can be the most challenging of the floral parts to interpret.〔 ==Pistils== The gynoecium may consist of one or more separate pistils. A pistil typically consists of an expanded basal portion called the ovary, an elongated section called a style and an apical structure that receives pollen called a stigma. *The ovary (from Latin ''ovum'' meaning egg), is the enlarged basal portion which contains placentas, ridges of tissue bearing one or more ovules (integumented megasporangia). The placentas and/or ovule(s) may be born on the gynoecial appendages or less frequently on the floral apex.〔〔〔〔 The chamber in which the ovules develop is called a locule (or sometimes cell). *The style (from Ancient Greek stülos meaning a pillar), is a pillar-like stalk through which pollen tubes grow to reach the ovary. Some flowers such as ''Tulipa'' do not have a distinct style, and the stigma sits directly on the ovary. The style is a hollow tube in some plants such as lilies, or has transmitting tissue through which the pollen tubes grow. *The stigma (from Ancient Greek , ''stigma'' meaning mark, or puncture), is usually found at the tip of the style, the portion of the carpel(s) that receives pollen (male gametophytes). It is commonly sticky or feathery to capture pollen. The word "pistil" comes from Latin ''pistillum'' meaning pestle. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Gynoecium」の詳細全文を読む スポンサード リンク
|