Botany lecture notes

Anomalous Secondary Thickening in Dracaena Stem: Lecture Notes and Diagram


anomalous secondary thickening in monocots

Anomalous Secondary Thickening in Dracaena
Anomalous Secondary Thickening in Monocots

Before going to the secondary thickening in Dracaena, first see what anomalous secondary thickening is and how the process of anomalous secondary thickening happens in plants.

What is Anomalous Secondary Thickening?

Ø  In many plants, the pattern of the secondary thickening shows deviation from the normal type.

Ø  The term “Anomalous Secondary Growth” is given for this deviation or variation.

Ø  The anomalous secondary growth is more common in tropical plants.

Ø  Anomalous secondary thickening is NOT an anomaly or disease in plants; rather it is an adaptation to suit the habit and habitat of the plant.

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Botany lecture notes

Apical Meristem in Shoot: Structure and Organization


shoot-apical-meristem

Shoot Apical Meristem
Apical Organization of Shoot Meristem

Apical meristem

Ø  Apical meristem is a patch of meristematic tissue present in the apex (tips) of shoot and roots in plants.  

Shoot apex:

Ø  Shoot apex is the growing tip of the stem.

Ø  It is an undifferentiated region with meristematic cells.

Ø  From this region the plant growth proceeds.

Ø  The shoot apex also produces lateral organs such as leaves, branches and flowers.

Ø  Below the apical meristem, different tissue zones are progressively differentiated.

apical-meristem

Tissue zones in the shoot apex

Ø  Three main tissue zones are present on the shoot apex of plants, they are:

$.  Protoderm: Protoderm gives rise to the epidermis of the plant.

$.   Procambium: Procambium gives rise to primary vascular tissue (xylem & phloem).

$.   Ground meristem (fundamental meristem): The ground meristem gives rise endodermis, pericycle, cortex, medulla and pith.

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biology-ppt-free-download

Secretory Tissue in Plants PPT (Structure, Classification and Examples)


Plant Science PPT

Secretory Tissue System in Plants PPT
(Structure, Classification, Functions and Examples of Secretory Tissues in Plants)

What is Plant Secretion? What are Secretory Tissues? How Plant Secretory System is Classified? Different Types of Secretory Systems in Plants, External vs Internal Secretory System in Plants, Glandular Trichomes, Nectaries and Hydathodes in Plants, Digestive Glands of Drosera, Salt Glands of Mangrove Plants, Colletors, Floral vs Extra-floral Nectaries, Water Stomata, Guttation, Internal Secretory Cells, Idioblasts, Cystoliths vs Raphides, Secretory Ducts and Cavities in Plants, Lysigenous vs Schizogenous Cavities in Plants, Laticifers in Plants, Articulate and Non-articulate Laticifers, Articulate Anastomosing and Articulate Non-anastomosing Laticifers, Chemical Composition of Latex and many more…

Learn more: Lecture Note in Secretory Tissue in Plants

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Botany lecture notes

Secretory Tissue System in Plants (Structure, Classification and Functions + PPT)


secretory cells

Secretory Cells and Tissues in Plants
(Structure and Classification of Secretory Tissue System in Plants with Examples)

What are plant secretions?

Most of the plants release many substances from their cell cytoplasm to the exterior and they are called as Plant-secretions. Among these secretions, some are beneficial to the plant and some are not. The beneficial substances secreted from the plant parts are called as secretions. The chemical composition of plant secretions highly varies. The secretions may be water, nectar, salt, tannins, resins, latex, gums, digestive enzymes, hormones etc.

Secretory Cell/Tissue

Cells or tissue associated with or facilitate the secretion is termed as the secretory cell or secretory tissue. The structure, arrangement and the origin of secretory cells/tissues highly varies.

Classification of Secretory Tissues

Ø  The secretory tissue is broadly classified into two categories based on their position in the plant body. They are

(I). External secretory tissue

(II). Internal secretory tissue

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Botany lecture notes

Hydathode or Water Stomata–Structure and Functions (Short Notes)


water stomata notes

Hydathode – Water Stomata
(Structure and Functions of Hydathodes)

What are Hydathodes?

Hydathodes are specialized pores (openings) particularly present on the leaf margins, which exudes or secretes drops of water. The exudation of water as drops from the tip or margin of the leaves is called guttation. The process of guttation is facilitated by the hydathodes.

Ø  They are also called as Water Stomata because they structurally resemble stomata and they facilitate guttation (secretion of droplets of water from the pores of plants).

Ø  Hydathodes are commonly found in Angiosperms, especially in grasses.

Ø  They are also present in some other plants such as water hyacinth, balsam, roses, Hibiscus and rarely in some non-angiospermic plants.

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