what is meant by extrastelar intrastelar secondry growth?explain
Secondary growth in plants is defined as the increase in thickness due to the growth of secondary tissues. The growth occurs in stellar region when cambium grows and in extra stellar region or cortical region when cork cambium starts growing in dicot plants. During secondary growth the cambium starts growing first resulting in thickness in stellar region. After that the cork cambium increases in width.
- Interstelar secondary growth
- 1. Occurs in the stelar region and secondary growth starts first.
- 2. Occurs by the activity of vascular and interfascicular cambium.
- 3. Produces secondary xylem and secondary phloem tissue.
- 4. Annual ring formation occurs.
- 5. Leads to formation of bark.
- 6. Produces more conductive tissues.
- Extra stelar secondary growth
- 1. Occurs in the extra stelar region after stelar secondary growth starts.
- 2. Occurs by the activity of cork cambium.
- 3. Produces cork cells and parenchyma cells.
- 4. No annual ring formation.
- 5. Leads to formation of periderm and lenticels.
- Produces protective tissues.