be in the form of stellate hairs (star shaped) present in plants. Example: styrax, many members of Malvaceae and Solanaceae. Unicellular hair Uniseriate unbranched hair Branched multiseriate hair Rhizodermis and root hairs Long cell Short cell (Trichoblast) Stellate hairs Figure . : Types of Trichomes Prickles Prickles, are one type of epidermal emergences with no vascular supply.
They are stiff and sharp in appearance. (Example: Rose). Figure . : Prickles Functions of Epidermal Tissue System .
This system in the shoot checks excessive loss of water due to the presence of cuticle. . Epidermis protects the underlying tissues. .
Stomata is involved in transpiration and gaseous exchange. . Trichomes are also helpful in the dispersal of seeds and fruits, and provide protection against animals. .
Prickles also provide protection against animals and they also check excessive transpiration . In some rose plants they also help in climbing. . Glandular hairs repel herbivorous animals.
. Fundamental Tissue System The ground or fundamental tissue system constitutes the main body of the plants. It includes all the tissues except epidermis and vascular tissues. In monocot stem, ground tissue system is a continuous mass of parenchymatous tissue in which vascular bundles are found scattered.
Hence ground tissue is not differentiated into cortex, endodermis, pericycle and pith. Generally in dicot stem, ground tissue system is differentiated into three main zones – cortex, pericycle and pith. It is classified into extrastelar ground tissue (Examples: cortex and endodermis) and intrastelar ground tissue (Examples: pericycle, medullary ray and pith) Extrastelar Ground Tissue The ground tissues present outside the stele is called extrastelar ground tissue. (Cortex) Intrastelar Ground Tissue The ground tissues present within the stele are called intrastelar ground tissues.
(pericycle, medullary rays and pith). cells with intercellular spaces. The cells in the pith generally stores starch, fatty substances, tannins, phenols, calcium oxalate crystals, etc. Albuminous Cells: The cytoplasmic nucleated parenchyma, is associated with the sieve cells of Gymnosperms.
Albuminous cells in Conifers are analogous to companion cells of Angiosperms. It also called as strasburger cells. . Vascular Tissue System This section deals with