Plant Tissues and Organs: Structure and Function
1. Meristematic Tissue
MeriStar: Primary Meristem
Responsible for plant growth. Growth in length occurs in the terminal buds of the stem and root.
MeriStar Side: Secondary Meristem
Growth in thickness, arising from the first year of life. Two types:
- Cambium: Internal, causes the conducting vessels.
- Phellogen: External, originates suber or cork.
2. Adult Tissue
ECJ. Parenchymatous Tissue
Forms the major part of the plant; it is a tissue filler. Four types:
- Parenchyma Chlorophyll: Cells have chlorophyll, enabling
Leaf Morphology: Structure, Development, and Types
Leaf Structure: Stem body, limited growth, dorsiventral symmetry, specialization to perform photosynthesis.
Leaf Parts
Pod: Widening rather than union with the stem. Petiole: Called up, leaf blade joins the stem when present. Lamina (Limbo Foliar): Simple leaf (pulvinus motor, rachis, rachilla, leaflets or pinnae, foliólulos or pinnules).
Foliar Succession (Phyllome)
Used to refer to all types of leaves of a plant:
- Cataphylls (Scales): Appear in the winter buds of underground stems, called Perula together.
Root Structure and Development in Plants
Root Cap Function and Origin
The root cap, or cofa, is a structure that protects the apical meristem of the root as it grows and penetrates the soil. It is composed of living parenchymal cells derived from the apical meristem. It originates from the caliptrogen in monocots and the calyptra-dermatogen in dicots. The root tip secretes mucilage, which aids in ion exchange, adherence to soil particles, and nutrient chelation. Root georeaction (response to gravity) is controlled by Ca++ and the hormone
Read MorePlant Tissues: Meristems, Protective, and Supportive Tissues
Primary Meristem
Primary meristem is located at the tips of young plant organs: the apex of the root, stem, buds, etc., where it is the cone of plant growth. It provokes these organs to grow in length.
Root
Distinct parts are: suberized zone, absorbent hairs zone, and root cap zone. The growth zone is the subterminal region where the root meristematic tissue is located, causing an increase in the organ’s length. You can find 1, 2, or 3 meristematic cells. If there is 1 cell, this cell originates all
Read MorePlant Anatomy: Glands, Roots, and Specialized Structures
Plant Glands: Types and Secretions
Glands: External Secretion of Mucilage Cells: Cells with large nuclei, thick cell walls, numerous dictyosomes, and vesicles in the periphery. They contain mucilage and exhibit granulocrine secretion.
Glandular Salt Structures: Plants that live in saline soils, known as halophytes (e.g., Atriplex), have an epidermis covered with vesicular hairs that accumulate salts. In Caragana, salts are stored in vacuoles. When the cell collapses, the liquid content evaporates,
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