an integrated group of cells with a common structure and function Tissues an integrated group of cells with a common structure and function
Plant Tissues Meristematic tissue: rapid cell division, lengthening of shoots and roots Dermal tissue: covering for the plant body Ground tissue: support, photosynthesis, and storage Vascular tissue: conduction of water, food, and dissolved minerals; strengthens and supports the plant
Plants Exhibit Localized Growth at Meristems
Meristematic Tissue specific areas of plant growth composed of cells that do not differentiate cells retain the ability to divide allow plants to grow their entire lives Types: Apical – primary growth at root and shoot tips Lateral – secondary growth in trees and shrubs Intercalary – secondary growth in monocot stems
Apical meristem In shoot tips and root tips Allium cepa root tip Region of cell differentiation/maturation Region of cell elongation In shoot tips and root tips Allium cepa root tip Region of cell division Apical meristem Root cap
Apical Meristems Stem buds have a dome-like apical meristem in addition to leaf primordia and bud primordia, which protect the apical meristem.
Dermal Tissue System
Dermal Tissues Epidermis Single layer of cells called the epidermis in herbaceous plants Guard cells Trichomes Root hairs Functions Absorption Secretion of cuticle Protection Control of gas exchange Cuticle
The Ground Tissue System
Parenchyma cells spherical-shaped cells found throughout plant thin primary walls living, metabolizing tissue functions: Photosynthesis & respiration Storage (starch, oil droplets, water, and salts) Wound healing & regeneration
Collenchyma beneath the epidermis in young stems and in large veins of leaves elongated cells that have unevenly thickened cell walls alive at maturity flexible support system found uniformly throughout the plant
Sclerenchyma structural support two types: fibers – support in wood, bark, leaves, stems sclereids – protection in fruits, seeds, other plant organs primary and secondary cell walls. dead at functional maturity The root of the word sclerenchyma is the Greek word root (sclero) meaning “hard”
The Vascular Tissue System
Complex Vascular Tissues Xylem Conducts water and dissolved minerals from the roots Phloem Conducts dissolved food materials, carbohydrates, in solution Continuous throughout plant Support plant body
All 4 types of tissues are present in the root tip
Young monocot stem Young dicot stem