TissuesTissues

an integrated group of cells with a common structure and function

Plant TissuesPlant Tissues

1. Meristematic tissue: rapid cell division, lengthening of shoots and roots

2. Dermal tissue: covering for the plant body

3. Ground tissue: support, photosynthesis, and storage

4. Vascular tissue: conduction of water, food, and dissolved minerals; strengthens and supports the plant

MeristematicMeristematic TissueTissue

� cells that do not differentiate

� cells retain the ability to divide

� Types:� Types:� Apical – primary growth at

root and shoot tips� Lateral – secondary growth

in trees and shrubs � Intercalary – secondary

growth in monocot stems

Apical Apical meristemmeristem

� In shoot tips and root tips

� Allium cepa root tip

Region of cell differentiation/maturation

Region of cell elongation

Root cap

Apical meristem

Region of cell division

Dermal TissuesDermal Tissues� Single layer of cells called the

epidermis in herbaceous plants� Guard cells� Trichomes

Epidermis

� Trichomes� Root hairs

� Functions� Absorption� Secretion of cuticle� Protection� Control of gas exchange

Cuticle

The Ground The Ground Tissue SystemTissue System

Parenchyma cellsParenchyma cells

� spherical-shaped cells

� found throughout plant

� thin primary walls

� living, metabolizing tissue

� functions:� functions:

� Photosynthesis & respiration

� Storage (starch, oil droplets, water, and salts)

� Wound healing & regeneration

CollenchymaCollenchyma

� beneath the epidermis in young stems and in large veins of leaves

� elongated cells that have unevenly thickened cell unevenly thickened cell walls

� alive at maturity� flexible support system� found uniformly throughout

the plant

SclerenchymaSclerenchyma� structural support� two types:

� fibers – support in wood, bark, leaves, stemsstems

� sclereids – protection in fruits, seeds, other plant organs

� primary and secondary cell walls.

� dead at functional maturity

The Vascular The Vascular Tissue SystemTissue System

Complex Complex Vascular TissuesVascular Tissues

� Xylem� Conducts water and dissolved

minerals from the roots

� PhloemConducts dissolved food � 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 dicot stem Young monocot stem