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

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.

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

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

• 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

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

• 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

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

• 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