Assertion: In some species of asteraceae and poaceae seeds are formed without fertilization.
Reason: Formation of fruit without fertilization is called parthenocarpy.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
B.
If both assertion and reason are true but reason is not the correct explanation of assertion
Formation of seeds without fertilization is called apomixis. It leads to clonal reproduction in which all offsprings are by and large genetically identical to the parent. The egg contains a full complement of genes and does not need to fuse with a sperm to produce a zygote. Apomixis provides for the perpetuation of traits favourable to individual survival but eliminates the longer-term evolutionary advantage of biparental inheritance. In Asteraceae, various genera and individual species of the order asterales are known to reproduce by apomixis (the setting of seeds without fertilization), either completely or in addition to normal sexual means.
In poaceae about 35 genera produce seeds without fertilization. On the other hand, parthenocarpy is development of fruits without fertilization. The fruit resembles a normally produced fruit but is seedless, e.g. pineapple, banana, cucumber, grape, orange, grapefruit etc.
Even after killing the generative cell with a laser beam, the pollen grain of a flowering plant germinates and produces normal pollen tube because
laser beam stimulates pollen germination and pollen tube growth
the laser beam does not damage the region from which pollen tube emerges
the contents of killed generative cell permits germination and pollen tube growth
the vegetative cell has not been damaged
Assertion : Protandry and protogyny ensures cross fertilization.
Reason : Cross fertilization introduces variation in progeny.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion : Pollen mother cells (PMCs) are the first male gametophytic cells.
Reason : Each PMC gives rise to two pollens.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Which one of the following pairs of plant structures has haploid number of chromosomes
Nucellus and antipodal cells
Egg nucleus and secondary nucleus
Megaspore mother cell and antipodal cells
Egg cell and antipodal cells
Assertion : Emasculation prevents self- pollination in flowers.
Reason : Emasculation is the removal of anthers from a bisexual flower.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
Assertion: Maize is an albuminous seed.
Reason: Endosperm is completely absorbed by its growing embryo
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
Apomixis is
formation of seeds by fusion of gametes
formation of seeds without syngamy and meiosis
formation of seeds with syngamy but no meiosis
none of the above
Assertion: Nuclear endosperm is formed by subsequent nuclear division without wall formation.
Reason: Coconut is an example of such endosperm, where the endosperm remains nuclear throughout the development of the fruit
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
