Differentiate between:
Absortion Spectrum and Action Spectrum

Differentiate between:
Racemose and cymose inflorescence

A pollen grain in angiosperm at the time of dehiscence from an anther could be 2-celled or 3-celled. Explain. How are the cells placed within the pollen grain when shed at a 2-celled stage ?

(a) Can a plant flowering in Mumbai be pollinated by pollen grains of the same species growing in New Delhi ? Provide explanations to your answer.

(a) When a seed of an orange is squeezed, many embryos, instead of one are observed. Explain how it is possible. 
(b) Are these embryos genetically similar or different ? Comment.

Describe any two devices in a flowering plant which prevent both autogamy and geitonogamy.

Explain the events up to double fertilisation after the pollen tube enters one of the synergids in an ovule of an angiosperm.

108.

Which one of the following statements is not true?

• Exine of pollen grains is made up of sporopollenin

• Pollen grains of many species cause severe allergies

• Stored pollen in liquid nitrogen can be used in the crop breeding programmes

• Stored pollen in liquid nitrogen can be used in the crop breeding programmes

In bryophytes and pteridophytes, transport of male gametes requires

• insects

• birds

• water

• water

Proximal end of the filament of stamen is attached to the

• connective

• placenta

• thalamus

• thalamus