Plant Developmental Biology: Endosymbiosis and Evolution

Study Notes

Endosymbiosis Theory

Eukaryotic cell engulfs bacterium, providing protection and carbon compounds, while bacterium supplies ATP.
This relationship led to the evolution of mitochondria and chloroplasts.

Evolution of Plant Development

Multi-cellular green organisms developed from eukaryotic plants' ancestors.
Examples of endosymbiosis in nature include secondary endosymbiosis and serial ingestion of photosynthetic bacteria.
Gene transfer among genomes and evolution of plastids like chloroplasts occurred.
Evidence of bacterial descent is seen in the position of mitochondria and plastid DNA in phylogenetic trees and DNA sequences.
Evolution of plants from green algae as plant ancestors, adapting to life on land with challenges and advantages.

Plant Structure and Function

Different plant structures, such as vascular spores, have unique functions.
Evolutionary timeline of plant types on land include key developments.

Growth and Development

Plant growth, development, and differentiation are influenced by factors like cell number and weight.
Parameters to measure plant growth include cell number and weight.
Types of growth:
- Primary Growth: Length increase from mitotic division at root and shoot apex.
- Secondary Growth: Diameter increase from secondary meristem.
- Unlimited/Indeterminate Growth: Continuous growth of root and shoot system.
- Limited/Determinate Growth: Leaves, fruits, and flowers stop growing after a certain size.

Meristematic Tissues

Shoot apical meristem and root apical meristem are types of meristematic tissues.
Meristems are regions with unspecialized cells for continuous division.
Characteristics of meristematic tissues include self-renewal quality, small and few vacuoles, dense protoplasm, and healing wounded plant tissues.

Classification of Meristem

Classification based on origin and position include apical, intercalary, and lateral meristem.
Secondary meristem is derived from primary meristem, with vascular cambium and cork cambium forming meristematic tissues.

Cell Types and Functions

Examples include sclerenchyma, phloem, collenchyma, parenchyma, transfer cells, etc., which have roles in support, transport, and metabolism.

Meristem Position

Apical meristem is located at root and shoot tips for primary growth.
Lateral meristems are responsible for secondary growth in stems, with vascular cambium and cork cambium contributing to width and girth.

Differentiation and Redifferentiation

Differentiation involves qualitative changes in plants for specialized functions.
Process where genetically identical cells become specialized.
Redifferentiation/transdifferentiation involves dedifferentiation, stem cell-like state, and differentiation, with factors like auxin, cellulase, and cell death playing roles.

Description

This quiz covers the endosymbiosis theory, explaining how mitochondria and chloroplasts evolved in eukaryotic cells. It also explores the development of multi-cellular green organisms and the evolution of plastids like chloroplasts.