Which type of endosperm does the coconut water represent?
Which type of endosperm does the coconut water represent?
The correct option is A Nuclear type
The endosperm is a tissue produced inside the seeds of most of the flowering plants following fertilization. It is triploid in most species. It surrounds the embryo and provides nutrition in the form of starch, though it can also contain oils and protein.
Three main types of endosperm development in flowering plants are: (i) Nuclear type (ii) Cellular type and (iii) Helobial type
1. Nuclear Endosperm:
In nuclear type of endosperm the first division of primary endosperm nucleus and few subsequent nuclear divisions are not accompanied by wall formation. The nuclei produced are free in the cytoplasm of the embryo sac and they may remain free indefinitely or wall formation takes place later. In the coconut, cell wall formation of endosperm is never found complete.
Cellular type: In this case, there is cytokinesis after each nuclear division of endosperm nucleus. The endosperm, thus, has a cellular form, from the very beginning because first and subsequent divisions are all accompanied by wall formation e.g. Petunia, Datura, Adoxa, etc.
(iii) Helobial type:
It is an intermediate type between the nuclear and cellular types. The first division is accompanied by cytokinesis but the subsequent ones are free nuclear. The chamber towards micropylar end of embryo sac is usually much larger than the chamber towards chalazal end. A large number of nuclei are formed in the micropylar chamber by free nuclear divisions while the nucleus of the chamber towards chalazal end divides to form a fewer free nuclei or may not divide at all.
The endosperm is a tissue produced inside the seeds of most of the flowering plants following fertilization. It is triploid in most species. It surrounds the embryo and provides nutrition in the form of starch, though it can also contain oils and protein.
Three main types of endosperm development in flowering plants are: (i) Nuclear type (ii) Cellular type and (iii) Helobial type
1. Nuclear Endosperm:
In nuclear type of endosperm the first division of primary endosperm nucleus and few subsequent nuclear divisions are not accompanied by wall formation. The nuclei produced are free in the cytoplasm of the embryo sac and they may remain free indefinitely or wall formation takes place later. In the coconut, cell wall formation of endosperm is never found complete.
Cellular type: In this case, there is cytokinesis after each nuclear division of endosperm nucleus. The endosperm, thus, has a cellular form, from the very beginning because first and subsequent divisions are all accompanied by wall formation e.g. Petunia, Datura, Adoxa, etc.
(iii) Helobial type:It is an intermediate type between the nuclear and cellular types. The first division is accompanied by cytokinesis but the subsequent ones are free nuclear. The chamber towards micropylar end of embryo sac is usually much larger than the chamber towards chalazal end. A large number of nuclei are formed in the micropylar chamber by free nuclear divisions while the nucleus of the chamber towards chalazal end divides to form a fewer free nuclei or may not divide at all.
