Question

1. into what three major portions can a young woody dicot stem be divided? 2. how are vessels and tracheids different? what type of vascular tissue do they constitute? 3. what is the difference between sapwood and heartwood? 4. how are annual growth rings formed? section review 4.2 herbaceous monocots the vascular bundles of herbaceous monocots are scattered throughout the stem. the older vascular bundles are near the center of the stem. the younger vascular bundles are toward the inside. the xylem is toward the inside. the phloem is toward the outside.

Explanation:

1. A young woody dicot stem can be divided into the epidermis, cortex, and stele. The epidermis is the out - layer for protection, the cortex is for storage and support, and the stele contains vascular and ground tissues.
2. Vessels are long - tube structures made of vessel elements for water and mineral transport, while tracheids are individual, elongated cells also for water transport but less efficient in bulk flow. Vascular tissue includes xylem (vessels and tracheids for water transport) and phloem for organic nutrient transport.
3. Sapwood is the outer, living part of the wood involved in water transport, while heartwood is the inner, non - living part, often darker in color and more resistant to decay.
4. Annual growth rings are formed due to the activity of the vascular cambium. In spring, when conditions are favorable, larger, thinner - walled cells (spring wood) are produced. In summer or fall, smaller, thicker - walled cells (summer wood) are formed. The boundary between the spring wood of one year and the summer wood of the previous year creates the annual growth ring.

Answer:

1. Epidermis, cortex, stele.
2. Vessels are long - tube structures of vessel elements for water/mineral transport; tracheids are individual elongated cells for water transport. Vascular tissue: xylem (vessels + tracheids) for water, phloem for organic nutrients.
3. Sapwood is outer, living, for water transport; heartwood is inner, non - living, more decay - resistant.
4. Formed by vascular cambium activity. Spring: larger, thinner - walled cells; Summer/Fall: smaller, thicker - walled cells. Boundary creates ring.