Sexual Reproduction In Flowering Plants

Concept: The tapetum is the innermost layer of the microsporangium (anther) wall and plays a vital role in pollen development.
Function of Tapetum:

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  Nourishment of Developing Microspores: Provides essential nutrients and metabolites required for the growth and maturation of pollen grains.
• 
  Formation of Pollen Wall: Secretes sporopollenin precursors that help in the formation of the exine (outer layer) of pollen.
• 
  Production of Enzymes and Proteins: Synthesizes enzymes and proteins that regulate pollen development.
• 
  Secretion of Pollenkitt: Produces sticky substances (pollenkitt) that help pollen adhere to pollinators.

Importance:

• Essential for viable pollen formation
• Abnormal tapetum leads to male sterility

Concept: Parthenocarpy is a biological phenomenon related to fruit development without fertilization.
Definition: Parthenocarpy refers to the development of fruit without fertilization of the ovule. As a result, the fruit formed is usually seedless.
Key Features:

• No fertilization occurs
• Ovary develops into fruit directly
• Produces seedless fruits

Example:

• Banana (common natural example)
• Seedless grapes (commercial example)

Importance:

• Improves fruit quality
• Preferred in commercial horticulture
• Can be induced artificially using plant hormones