Multiple Choice QuestionsThe development ofsporangium in Pteridium is
a leptosporangiate type
an eusporangiate type
Both (a) and (b)
None of the above
In a flowering plant, archesporium gives rise to
wall and tapetum
only tapetum and sporogenous cells
only wall of the sporangium
both wall and sporogenous cells
The growth of pollen tube towards embryo sac is
geotropism
chemotaxis
thigmotaxis
phototaxis
B.
chemotaxis
The growth of pollen tube towards ovary is due to chemical stimulus and is called chemotropism or chemotaxis.
Geotropism is the growth of the parts of plants in response to the force of gravity. The upward growth of plant shoots is an instance of negative geotropism ; the downward growth of roots is positive geotropism.
Thigmotaxis is the motion or orientation of an organism in response to a touch stimulus.
Phototaxis is the bodily movement of a motile organism in response to light, either towards the source of light ( positive phototaxis ) or away from it ( negative phototaxis ).
A hyaline bisexual and self-fertilized flower that does not open at all is
chasmogamaus
apogamous
cleistogamous
polygamous
What is true about a gamo spermous apospory?
Formation of embryo from egg of embryo sac proliferated from a nucellar cell
Formation of embryo from egg of embryo sac formed directly from megaspore mother cell
Formation of embryo directly from nucellus
Formation of embryo directly from integument
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