Phanerogams-Gymnosperms (IFS (Forests Services) Botany (Mains)): Questions 1 - 8 of 12

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Question number: 1

» Phanerogams » Gymnosperms

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Appeared in Year: 2015

Essay Question▾

Describe in Detail

Draw the LS of Pinus seed (Paper-1, Section-A)

Explanation

Image showing Pinus seed L.S.

Image Showing Pinus Seed L. S

Pinus is gymnosperms and it has a naked seed. After the gametophyte ovum is fertilized to become a zygote and the ovule becomes a seed.

Question number: 2

» Phanerogams » Gymnosperms

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Appeared in Year: 2015

Essay Question▾

Describe in Detail

Discuss the stages of development of male gametophyte in Pinus before pollination. (Paper-1, Section-A)

Explanation

Spores are the main units for the gametophytic life cycle.

  • In pinus, spores are mainly two types; microspores and megaspores.

  • Microspores are germination to give rise to male gametophyte and megaspores germination to give rise to female gametophyte.

  • In Pinus male gametophyte, microspore is the unit of it.

  • Microspore is also called as pollen grain.

  • Polle

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Question number: 3

» Phanerogams » Gymnosperms

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Appeared in Year: 2014

Essay Question▾

Describe in Detail

Comment on the structure, location and function of transfusion tissue. (Paper A Section A)

Explanation

Definition:

  • Transfusion tissue is lying on the vascular bundles of gymnosperm leaves and consists of both living cells like those of parenchyma with walls that are not lignified and thin-walled but lignified tracheids with bordered pits.
  • Transfusion tissue is composed of tracheids with bordered pits and parenchyma cells containing tannin-like substan

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Question number: 4

» Phanerogams » Gymnosperms

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Appeared in Year: 2014

Essay Question▾

Describe in Detail

Why are gymnosperms called naked-seeded plants? (Paper - 1, Section - B)

Explanation

  • Gymnosperms do not produce fruit, their seeds are naked or exposed to the elements without a layer of fruit to protect them.

  • Gymnosperms are different from angiosperms on the basis of the naked-seed habit and enclosure of seeds within a fruit in the latter.

  • Gymnosperm pollen lands directly on the ovule, where in angiosperm pollen lands on the stigma

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Question number: 5

» Phanerogams » Gymnosperms

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Appeared in Year: 2014

Essay Question▾

Describe in Detail

Draw scientifically accurate diagrams of the following and label the parts: Anatomy of Pinus needle (Paper - 1, Section - B)

Explanation

Image showing Pine needle anatomy.

Image Showing Pine Needle Anatomy

Anatomy of Pinus needle or Pinus leaf:

Epidermis:

  • Single layered, thick walled and cutinized.

  • Stomata are distributed the entire surface of the leaf, so the leaf is described as amphistomatic.

  • The guard cells of the stomata are sunken below the level of epidermis.

  • Below the stomata there is an air-cavity.

Hypodermis:

  • Hypod

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Question number: 6

» Phanerogams » Gymnosperms

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Appeared in Year: 2013

Essay Question▾

Describe in Detail

Write brief and critical notes on the following: Affinities of Gymnosperms with Angiosperms (Paper 1, Section B)

Explanation

  • The plants are woody and perennial.

  • The stele is eustelic. Secondary growth as in dicots. The secondary wood may be manoxylic or pycnoxylic.

  • The vascular tissue is well developed, but vessels are absent (except in Gnetum). Phloem is devoid of companion cells.

  • Both are heterosporic and endosporic.

  • Megaspore is retained in the megasporangium resulting in

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Question number: 7

» Phanerogams » Gymnosperms

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Appeared in Year: 2013

Essay Question▾

Describe in Detail

Write brief and critical notes on the following: Manoxylic and Pycnoxylic wood (Paper 1, Section B)

Explanation

The secondary wood in the gymnosperms may be manoxylic or pycnoxylic.

Manoxylic wood:

  • Manoxylic wood is soft and parenchymatous.

  • Manoxylic wood is not commercially useful.

  • Manoxylic wood is the non-compact wood with large pith and cortex mixed with less amount of xylem tracheids or wood.

  • Parenchyma cells are filled with starch grains.

  • Manoxylic wood is s

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Question number: 8

» Phanerogams » Gymnosperms

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Appeared in Year: 2014

Essay Question▾

Describe in Detail

Why gymnosperms are called naked seeded plants?

Explanation

  • The earliest seed plants produced seeds that sat unprotected on the surface of leaves or modified stems.

  • As they are first vascular plants that are totally independent of water bodies for their fertilization as there e ancestor needs water for their fertilization purpose.

  • These first seed plants hide their seed beneath their cones scales or specific

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