Mr. Bastin - ZooBot - Plant Organs + Flowers/Fruit

Types of Plant Tissues

-Meristematic (source of other tissue types

-Dermal (epidermal cells, cuticle)

-Vascular (xylem and phloem)

-Ground (Parenchyma, Collenchyma, Sclerenchyma)

Meristematic Tissue

groups of undifferentiated, actively dividing cells

-source of other tissue types

produce cells by mitosis

Dermal Tissue

-outer covering of a plant

-typically single layer of EPIDERMAL CELLS

-often covered by a waxy CUTICLE

> prevents water loss

Vascular Tissue

Xylem:

-conducts water

-Consists of narrow TRACHEIDS and wide VESSEL ELEMENTS

> die when mature and cytoplasm disintegrates

>form tubes through which water moves (upwards - soil to leaves)

VASCULAR CAMBIUM in between xylem and phloem

Phloem

-conducts food (down, leaves to fruit)

>ex. sugars concentrate in fruit

-consists of SIEVE TUBE ELEMENTS and COMPANION CELLS

Ground Tissue

located between dermal and vascular tissue

Parenchyma:

-predominant type

-large vacuoles for water storage

-lots of chloroplasts (lots of photosynthesis)

Collenchyma:

-provide support

>ex. "strings" of celery

Sclerenchyma

-provides support

-thick cell walls

Types (roots)

Taproots

-central, primary root

Fibrous

-branched

-relatively uniform in size (pretty small)

Structure (roots)

4 types of tissue

-Dermal (outside

-Vascular (center)

-Ground (inbetween)

-Meristematic (tip of roots)

-EPIDERMIS covered w/ ROOT HAIRS

>increase surface area

-end protected by ROOT CAP

Function (roots)

-anchor plant

-acquire water and minerals

> Minerals move via ACTIVE TRANSPORT (Adenosine PPP)

> Water in via OSMOSIS resulting from increased mineral concentration inside root

Function (stems)

-produce leaves, branches, flowers

-support

-transport (water: roots to leaves, food: leaves to roots

Structure (stems)

Nodes - where leaves and buds attach

Internodes - between nodes

Tissue arrangement

-monocots

>VASCULAR BUNDLES scattered throughout stems

>>xylem faces in, phloem out

-dicots

>VASCULAR BUNDLES arranged in organized ring

>area inside ring called PITH

Growth (stems)

Primary (increases length)

-occurs at APICAL MERISTEMS (at tips)

Secondary (increases width)

-occurs in LATERAL MERISTEMS (around plant)

>CORK CAMBIUM - outer covering

>VASCULAR CAMBIUM - forms between xylem and phloem and produces new xylem and phloem

Growth (stems) : Wood (xylem/phloem)

wood = layers of xylem

-heartwood = oldest xylem toward the center of stem

>no longer functions

-sapwood

>active in transport

phloem

-old pushed out and broken w/ growth

Growth (stems) : Wood: Rings

-early season growth = light colored xylem

-later season growth = darker xylem

-indicates aga and environmental conditions

Structure (leaves) : parts and shape

Blades - flat, collect light

Petiole - thin stalk

Shape:

-simple

> single blade attached to petiole

-compound

>multiple leaflets attached to petiole

(distinguish by looking for bud at base of petiole)

-pinnately compound

>leaflets spaced along the length of the petiole

-palmately compound

>leaflets attached at the tip of the petiole

Structure (leaves) : mesophyll

interior cells w/ chloroplasts

-carbs produced w/in move into phloem, carried to rest of plant

types:

-palisade mesophyll = outer layer

-spongy mesophyll = loosely connects interior

Structure (leaves) : stomata and guard cells

Stomata

-openings in underside for gas exchange (top for aquatic plants)

> carbon dioxide in and oxygen out

Guard cells

-regulate opening/closing of stomata

>water pressure w/in high, open

>water pressure w/in low, closed

Water transport (leaves)

evaporation

-water exiting stomata creates osmotic pressure

>pulls water up from roots

Capillary action (water movement through surface tension)

-cohesion/adhesion pulls water up the xylem

Function (flowers and fruit)

Reproductive organs of angiosperms

-most produce both male and female gametophytes

4 types of specialized leaves (f+f)

sepals:

-outermost circle, typically green

-enclose the bud prior to opening

petals:

-inside sepals, brightly colored

stamens:

-male parts which contain:

>filament

>>thin stalk

>anther

>>sac at top of filament

>>produce male gametophytes (pollen grains)

pistil (may contain many carpels):

-female parts in center which contain:

>ovary

>>base where haploid female gametophyte is produced

>style

>>thin stalk

>stigma

>>where pollen grain enters

Pollination

male gametophyte = pollen grain

female gametophyte = sac w/in ovary

Gymnosperms: typically wind pollination

-produce huge amounts of pollen

Angiosperms: typically animal pollination

-very efficient

-bright colors attract pollinators

-nectar as a bribe

Fertilization (angiosperms)

Steps:

- pollen grain lands on stigma

-pollen tube forms

>from grain into stigma to style to ovary

-double fertilization

>nucleus w/in pollen grain divides to form 2 sperm nuclei

>>1 fuses w/ egg to produce zygote

>>1 fuses w/ 2 endosperm nuclei to form a 3N cell

>>>forms endosperm to nourish seedling

Formation (seeds and fruits)

-zygote grows into embryo w/in seed

-ovary walls thicken to form a fruit

>fruit = ripened ovary w/ seeds

Dispersal (seeds and fruits)

-the purpose of the fruit

-by animals

>digest fleshy part

>seed coat protects during passage through digestive system

>feces = fertilizer

-by water/wind

Dormancy (seeds and fruit)

-embryo alive but not growing

-time for dispersal/better conditions

>warm temp in spring

>sun/nutrients after fire

>wash up on shore

Germination (seeds and fruit)

-early growth stage of embryo

>seed absorbs water

>swells

>cracks open seed coat

-root emerges through

Monocot vs Dicot

Monocot= one cotyledon; veins parallel; vascular bundles scattered randomly; flower in multiples of 3; no cambium

Dicot= 2 cotyledons; veins netlike, vascular bundles in a ring; flower in 4 or 5; cambium present