Lecture 4 - plant tissues and the fundamental palnt bodies

Root, Stem, and Leaf

three basic plant organs

Root

Anchors a vascular plant, Absorbs minerals and water, and Stores nutrients.

Stem

Alternating system of nodes and interodes

Leaf

Main photosynthetic organ

Flower, Fruit, and Seed

Reproductive Structures/Organs

Shoot

Produce food by photosynthesis, Carry out reproductive functions, and All parts found above ground.

Roots

Anchor the plant, Penetrate the soil and absorb water and dissolved minerals, and Store food.

Dermal tissue system, Vascular tissue system, and Ground tissue system

Each organ of a plant has three tissue systems:

Tissues

group of cells that forms a structural and functional unit

Simple permanent tissues

Made up of only one type of cell. e.g. Parenchyma Tissue, Collenchyma Tissue, Sclerenchyma Tissue, and Epidermis.

Complex permanent tissues

Composed of a mix of cell types. e.g. Xylem, Phloem, and Periderm.

Secretory Structures/Tissues

One or more types of cells. e.g. Glandular epithelium, laticifers, resin ducts, nectaries

Epidermis

Covers and protects plant surfaces. Secretes a waxy, waterproof cuticle.

Cuticle

lines the outer wall of the epidermal cells. made up of waxy material that protects plants from desiccation.

periderm

n plants with secondary growth, _ replaces epidermis.

Xylem

Composed of vessels, tracheids, parenchyma, fibers and ray cells

Xylem

Conducts water and dissolved minerals

Xylem

Conducting cells are dead and hollow at maturity

Phloem

Composed of sieve tubes, companion cells, parenchyma, fibers, ray cells

Phloem

Transports sugars. Main conducting cells are sieve-tube members.

Companion cells

assist phloem in the loading of sugars

Periderm

replaces the epidermis on plants with active lateral meristems.

Cork cells

fit tightly together and are dead at maturity.

Periderm

composed of Phellogen, Phellem (cork) and (Phelloderm) parenchyma

Secretory Structures/Tissues

Responsible for making latex, resins, nectar and other substances produced and stored in channels inside the plant body.

Meristems

mass of self- perpetuating cells, which are not yet comitted to developing into a specialized cell type.

Apical/Terminal meristem

Elongate the stem and the roots

apical meristem

new cells elongate and start to differentiate into primary tissues.

Apical Meristem

Located at the tips of stems and roots, Results in an increase in plant length, and is Responsible for primary growth; primary tissues; primary plant body.

Protoderm, Ground meristem, Procambium

Partly differentiated meristematic cells

Promeristem

apical initials and cells derived from them and still close to them

epidermis

protoderm differetiate into _

ground tissue

ground meristem differentiate into_

primary vascular tissue

procambium differentiate into_

Lateral Meristems

Also cambial meristem or cambium

Lateral Meristems

Increase girth of older roots and stems

Lateral Meristems

Responsible for secondary growth, Form secondary tissues.

secondary vascular tissue

Vascular cambium differtiate into_

Periderm

Cork cambium differetiate into_

Intercalary Meristems

A region of meristematic cells usually at the base of leaves and internodes in monocotyledous plants.

Dermal Tissue System, Vascular Tissue System, and Ground Tissue System.

Tissue systems

Dermal Tissue System

Outer protective covering

Vascular Tissue System

Transports materials between root and shoot

Xylem

conveys water

Phloem

transports organic nutrients

Ground Tissue System

everything that isn’t dermal and vascular

Pith

internal to the vascular tissue

Cortex

external to the vascular tissue

Primary tissues

Come from the apical meristem, compose the primary plant body.

Secondary tissues

Come from the lateral meristem, compose the secondary plant body.

cortex

Just under the epidermis, Contains primarily of parenchyma.

Vascular cambium

formed from meristematic cells, which are derived from the procambium or ground meristem.

Primary phloem

conduction of organic food materials. e.g. Seive tubes, companion cells, phloem parenchyma, phloem fibrs.

Primary xylem

Conduction of water and minerals. e.g. Tracheids, vessel elements, xylem parenchyma, xylem fibers.

pith

The central portion or core

pith

Consists of parenchyma and Storage.

Secondary Phloem

cells are very similar to the primary phloem. difference is only at the mode of origin.

Secondary xylem

Cells are also very similar to the primary xylem.

phellogen

cells of the cork cambium

phelloderm

cell layer behind the phellogen

phellem

cork cells

suberin

fatty material in the cell walls taht render cork being relatively impermeable to water and gases

ray initials and fusiform initials

vascular cambium has two types of cells

ray initial

cuboidal in shape

fusiform initials

elongated shape

cork

one of three parts of the periderm

bark

refers to all the tissues outside the vascular cambium, including the periderm