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词汇 Plumula
分类 英语词汇 英语翻译词典
释义

Plumula

英语百科

Seedling

Grass seedlings, 150-minute time lapse
Monocot (left) and dicot (right) seedlings
Seedling of a dicot, Nandina domestica, showing two green cotyledon leaves, and the first

A seedling is a young plant sporophyte developing out of a plant embryo from a seed. Seedling development starts with germination of the seed. A typical young seedling consists of three main parts: the radicle (embryonic root), the hypocotyl (embryonic shoot), and the cotyledons (seed leaves). The two classes of flowering plants (angiosperms) are distinguished by their numbers of seed leaves: monocotyledons (monocots) have one blade-shaped cotyledon, whereas dicotyledons (dicots) possess two round cotyledons. Gymnosperms are more varied. For example, pine seedlings have up to eight cotyledons. The seedlings of some flowering plants have no cotyledons at all. These are said to be acotyledons.

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