Review on tapetal ultrastructure in angiosperms.

Area of Science:

• Plant reproductive biology
• Cell biology
• Developmental biology

Background:

• The tapetum is a vital nutritive tissue in anthers, crucial for microspore development.
• Understanding tapetum ultrastructure is key to comprehending its diverse functions.
• Existing literature lacks comprehensive reviews on tapetum ultrastructure.

Purpose of the Study:

• To compile and review existing knowledge on tapetum ultrastructure across various plant species.
• To establish a foundation for future research into tapetum functions and development.
• To identify common and unique ultrastructural traits and their relation to tapetum types and functions.

Main Methods:

• Systematic review and compilation of ultrastructural data from 80 plant species across 45 families.
• Categorization of tapetum types: secretory, plasmodial, and invasive non-syncytial.
• Analysis of ultrastructural changes during microsporogenesis and microgametogenesis.

Main Results:

• Detailed ultrastructural characteristics of secretory, plasmodial, and invasive non-syncytial tapeta were documented.
• Specific ultrastructural traits associated with androsterility were identified.
• Variations in tapetum ultrastructure were observed across species and families, indicating no single model.
• Ultrastructural changes correlate with tapetum function and developmental stage.

Conclusions:

• Tapetum ultrastructure provides critical insights into its diverse functions and developmental roles.
• The study highlights the need for further research into novel tapetal organelles and their functions.
• Understanding tapetum ultrastructure aids in distinguishing genuine tapetal degeneration from preparation artifacts.
• Ultrastructural variations are linked to metabolic regulation and normal/abnormal tapetum development.