Plant Growth and Movement
Introduction
- Plants grow and develop in a highly organized sequence from a fertilized egg (zygote) to a mature plant with roots, stems, leaves, flowers, fruits, and seeds.
- Development involves two main processes: growth (increase in size) and differentiation (specialization of cells into specific types).
- The first step in plant growth is seed germination, triggered by favorable environmental conditions.
- Seeds remain dormant when conditions are unfavorable and resume growth when conditions become suitable.
- Plants go through vegetative (non-reproductive) and flowering (reproductive) phases.
- Vegetative phase precedes flowering, allowing the plant to establish roots, stems, and leaves for optimal growth before allocating resources to reproduction.
- All plant organs are composed of different types of tissues, each with specific structures and functions.
- Cells make up tissues, which form organs, and their structures are tailored to perform specific functions like photosynthesis (in leaves) or support (in stems).
- Developmental processes in plants are governed by intrinsic (internal) and extrinsic (external) factors.
- Intrinsic factors include genetic programming and hormonal regulation, while extrinsic factors encompass environmental cues like light, temperature, and nutrients.
- The structure and function of plant cells, tissues, and organs can be altered by genetic mutations, environmental stressors, or developmental signals.
- Such alterations may lead to changes in growth patterns, metabolism, or response to stimuli.
- The life cycle of a plant involves growth, reproduction, and eventual senescence (aging and death).
- Leaves, flowers, and fruits have limited lifespans and undergo periodic shedding or senescence, while the main plant body continues to grow and produce new tissues.
