Seedling - Misho

It is the sowing of seeds and allowing them to germinate, but it is a term usually used to distinguish between different propagation methods. Seedling is a sexual propagation method, as opposed to vegetative propagation (asexual propagation) which uses parts of the plant body, such as cuttings and layers. Seedling propagation is mainly used for mass production of tree seedlings and rootstocks for grafting, as well as for improving varieties of fruit trees, flowering trees, and forest trees, but it takes a long time for them to flower.

Depending on the species, seeds can be divided into those that can be stored and those that are sown immediately (also known as "take-sown"). Germination conditions are heavily influenced by moisture, temperature, oxygen, etc., but some seeds are photophilic (will not germinate unless they are exposed to bright light) and others are photophobic. Some seeds are difficult to germinate unless they are exposed to low or high temperatures for a certain period of time. Also, seeds with pulp will often be delayed in germination and will not be uniform if they are not washed and removed with water. Note that grass flowers and vegetables are not normally called seedlings, but are called "sown seeds" or "hashu".

[Yasuo Hori]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

種子を播(ま)いて発芽させることであるが、普通は繁殖の方法を区別するときに用いる用語である。挿木や取木のように植物体の一部分を用いて殖やす栄養繁殖（無性繁殖）に対し、実生は有性繁殖である。実生繁殖は主として樹木の苗木、接木(つぎき)用台木の大量生産に利用されるほか、果樹、花木、林木の品種改良にも用いられるが、開花までに長い期間を要する。

　種子は樹種により保存できるものと、すぐに播く（取り播きともいう）ものに区別できる。発芽条件には水分、温度、酸素などが大きく関係するが、種子によっては好光性（明るくないと発芽しない）のものと嫌光性のものがある。一定期間低温や高温を受けないと発芽しにくいものもある。また果肉のあるものは水洗いをして除去しないと、発芽の遅れやそろいが悪いことが多い。なお草花、野菜などは普通、実生とはよばず、種子播き、播種(はしゅ)という。

［堀　保男］

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