perisperm

Japanese: perisperm

...Plant that store these nutrients in the endosperm include parsley, persimmon, eggplant, and rice. The nucellus usually disappears or becomes membrane-like, but it can grow by storing nutrients and become a perisperm, as in Swiss chard. Seeds that store nutrients in the endosperm or exosperm are called albuminous seeds.

From [Endosperm]

...In other words, the two sperm nuclei that enter the embryo sac fertilize the egg nucleus and become an embryo, and the other fertilizes the two polar nuclei and becomes a triploid ( 3n ) primary endosperm nucleus, which undergoes cell division (or just nuclear division) to increase in volume and cell number, storing starch, protein, oil, etc. to become endosperm. The nucleus of the ovule usually disappears or becomes a thin membrane, but in some cases, such as Swiss chard and pepper, nutrients are stored in this nucleus, which is called the perisperm (also called the exosperm or outer sperm). During the seed maturation process, the nutrients stored in the endosperm are absorbed by the embryo, and in some cases nutrients are stored in the cotyledons, which are part of the embryo. ...

*Some of the terminology that mentions "perisperm" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…この養分を胚乳にたくわえたものに，セリ，カキ，ナス，イネがある。珠心は普通，消失したり膜状となるが，養分をたくわえて大きくなり，フダンソウのように外胚乳perispermとなることがある。胚乳や外胚乳に栄養分をたくわえたものを胚乳種子albuminous seedという。…

【胚乳】より

…すなわち，胚囊に入った二つの精核は卵核と受精し胚になり，他の一つは二つの極核と受精し，三倍体(3n)の初生胚乳核primary endosperm nucleusとなり，細胞分裂(または核分裂のみ)をして細胞数とともに体積を増し，デンプン，タンパク質，油脂などをたくわえ胚乳となる。胚珠の珠心は，普通，消失するか，薄い膜状となるが，フダンソウ，コショウのようにこの珠心に養分がたくわえられることがあり，これを周乳perisperm(外胚乳，外乳ともいう)と呼ぶ。種子が成熟する過程で，胚乳にたくわえられる養分が，胚によって吸収され，胚の一部である子葉に養分がたくわえられるものがある。…

※「perisperm」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典第２版について | 情報

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