Lesson 3: CRSC UPSTEP Anatomy Of Plants

Tissue

composed of cells usually similar in structure and function simple if it contains one cell type. more complex its made up of several types of cell

Organ

composed of several tissues with distinct structures and function

System

composed of interacting organs that coordinate as a functional complex in the life of the organ

Meristematic tissue

where cell division (mitosis) occurs

Apical meristem

tip of stem and roots (shoot or root apical meristem); gives rise to primary meristem

Lateral meristem

plant tissues that cause stems and roots to grow wider and thicker

Intercalary meristem

internodes and bases of young leaves

Permanent tissue

derived from meristems that have attained maturity form, thus perform specific function or functions

Epidermis

Outer covering of plant body. Modified to form stomata and hairs

Stomata

openings in the epidermis mainly on lower leaf surface, regulate gas exchange

Hairs

Protection, absorption, and excretion

Parenchyma

Found in all tissue systems, Living cells capable of further division, Provide new cells for growth (meristematic), Function for food production and storage (mesophyll cells)

Collenchyma

Thickened tissue in the cortex of the stem and petioles or along the veins of the leaves. Alive at maturity and have only a primary wall. Mature from meristem derivatives that initially resemble parenchyma, but differences quickly become apparent.

Sclerenchyma

(from the Greek skleros, hard) Hard and tough cells with a function in mechanical support. Scattered throughout the plant, found in both primary and secondary tissues

Fibers, Schleroids, Cork

Type of Sclerenchyma

Fibers

known as bast fibers; long, thin cells with very thick walls often dead at maturity

Schleroids or stone cells

similar with root cap

root cap

protects the tender apex (absent in aquatic plants); fibers, thick walled and lignified; may be living or dead at maturity

Cork

outermost tissue; impregnated with suberin (waxy substance)

Xylem

Carries water and mineral salts upward the plant body

Vessel elements

main conducting cells

Xylem parenchyma cells

transport selected solutes into and out vessel elements

Phloem

Distributes the dissolved food materials between the source and sinks

sieve tube element

chief food conducting element

companion cells

parenchyma cells always found beside the sieve tubes: move food in and out of the sieve tube member

phloem parenchyma

like ordinary parenchyma cells in the phloem

phloem fibers

like sclerenchyma cells

Ground

Packing and supportive tissue that forms much of the bulk of young plants Functions in food manufacture and storage Contains three main cell types: parenchyma, collenchyma, and sclerenchyma

Dermal tissue

The plant's protective outer covering in contact with the environment
Facilitates water and ion uptake in roots and regulates gas exchange in leaves and stems

Vascular tissue

Together with phloem and xylem, form a continuous vascular system throughout the plant Conducts water and solutes between organs and provides mechanical support

Region of cell division

one to few mm above the root cap; has small cells with thin walls, dense with protoplasm: undergo repeated cell division (meristematic region)

Region of elongation

lies above the meristematic region; extends to 1 to 5 mm; undergoes rapid elongation and enlargement; responsible for growth in root length

Region of maturation

lies above the meristematic region of elongation:

Tap root system

Primary root grows vertical downward. Branches grow downward or horizontally outwards

Tap root

functions that absorb water, minerals, and salts from soil and anchorage which can be modified to perform other functions

Adventitious root system

roots that grow from any part of the plant body other than radicle (base of stem, node, internode, branch, leaf: special circumstances)

Foliar Root System

Roots that originate from the leaves, typically from the petiole or a vein. Their development can be spontaneous or induced by injury.

Fibrous Root System

Characteristic of monocots, this system is entirely composed of adventitious roots.

STEM

Organ that support and conduct, initially developed from the epicotyle

stem

Major parts: bark, pith and wood (composed of xylem made up of vessels, fibers and parenchyma cells)

culm

flowering stem of grasses and sedges

offset

like runner, originates from leaf axil as a short and thickened branch away from the mother plant

rhizome

horizontal underground stem

runner or stolon

indeterminate aboveground stem with internodes and new plantlet at the tip

sucker

shoot arising below the ground from old stem

tendril

slender coiling branch for climbing

tiller

shoot produced from the base of the stem or culm

tuber

thick storage underground stem

corm

enlarged solid fleshy base

Erect or strong stem

unbranched; erect: cylindrical; stout: slim jointed stem with solid nodes and hollow internodes

weak trailing stem

on ground without rooting at the nodes

creeping stem

runner, stolon, offset or sucker climbing stem

Leaf

responsible for food manufacture, exchange of gases and respiration, transpiration

Leaf base

part attached to stem

Petiole

stalk of leaf

Leaf blade or lamina

the expanded portion of the leaf

Parallel

veins parallel to each other

Reticulate

network type of veins

Herbs

soft stemmed plants

Shrubs

medium sized, hard, woody stemmed plants; profusely branching
Trees

Climbers

thin, long stem with diffuse branches; develop tendrils and climbing roots

FLOWER

reproductive structure of flowering plants

Complete Flower

has all four parts (sepals, petals, pistil and stamen)

Incomplete Flower

lacking sepals, petals, pistil or stamen

Calyx

lowermost whorl of modified leaves. also known as sepals

Corolla

whorl of petals above the sepals

pistil

group of carpels in the center or at the top of the flower

Gynophore

stipe of a pistil or carpel

Pedicel

stalk of a flower

Perianth

combined calyx and corolla

Petal

a unit of corolla

Sepal

a unit of calyx

Stamen

male sporophyll within the flower

Seed

a ripened ovule which, when shed from the parent plant, consists of embryo and stored food supply, both enclosed in a seed coat or covering

Dicotyledon

embryo lies within an axis of two cotyledons

Monocotyledon

consists of seed coat, endosperm, and embryo

Embryo

developing plant inside the seed; has cotyledons (embryonic sonu bavare leaves), a root cap, a food source and a plumule (shoot)

Hilum

the scar on a seed coat at the location where it was attached to the plant's stalk during development

Micropyle

small pore in a seed that allows water absorption

Root

the part of the stem of a sprouting plant that is above the root and below the stalk of the cotyledon (seed leaves)

Hypocotyl

other term for root

Seed coat

outer protective layer covering the seed

Testa

other term for seed coat

Seed leaf

embryonic leaf within a seed

Cotyledon

other term for seed leaf

Plumule

shoot of an embryo

Orthodox

dries out naturally on mother plant to a low MC (≤ 20%)

Orthodox

can be dried to low MC (<5%) without damage

Orthodox

can be stored at low temperature(e.g. rice, corn, beans, vegetable seed. pili, etc.)

Recalcitrant

does not dry out normally on mother plant; shed in moist condition (50-70% MC)

Recalcitrant

seed larger than orthodox - embryo is only 15% of orthodox

Recalcitrant

killed if MC is reduced below critical level (12-30%)

Recalcitrant

susceptible to freezing (below 0°C) or chilling (10-15C)

Intermediate

can withstand desiccation to about 10-12% MC and can be stored under hermetic condition

Intermediate

loses viability more rapidly at low temperature (<10°C) than at warm temperature (12-21C)

Fruit

mature, ripened ovary

Fruit

contains the seed (ripened ovules) and pericarp (the tissue that surrounds the seeds)

Simple fruit

one fruit develops from single ovary of a flower with or without accessory parts e.g. corn, peanut

Aggregate fruits

collection of simple fruits developing from apocarpous pistil of a flower e.g. strawberry

Multiple or composite fruits

develop from a number of flowers from an inflorescence