05 - Complex plant tissues

Complex plant tissues and function

Often more than one function per tissue

Specialization for protection, exchange, uptake, transport, support and storage

types of Complex plant tissues

epidermis, periderm, xylem, phloem, ground tisssue

Epidermis function

protection, exchange, uptake

parts of epidermis

epidermis cells

cuticle

stoma

glands

hair

chracteristics of epidermis

Non-woody plants, one cell layer thick, alive

function of epidermis cells

protection

function of cuticle

protection

Cuticle

waxy layer: fatty substance (cutin)

Thickness ≈ water permeability → resistance to bacteria and other pests

function of stoma

2 guard cells; H2O & gas exchange

stoma

Stoma: two bordering guard cells (specialized epidermis cells)

stoma pressure

Dry conditions, low H2O pressure

Wet conditions, High H2O pressure

when are guard cells swollen or shrunken

when open they swollen

when closed they shrunken

function of glands

protection

example of glands

female canabis plants have glands with poison to keep away insects

what are hairs also known as

trichome

what are glands also known as

glandular trichome

what are platelet also knwon as

flatteneted trichome

difference between gland and hair

glands have a tip contining something

what is a platelet

more specilized hair

enlarging into umbrella

funtion of hair -

defense against herbivores and heat

sometimes modified into stinging hairs

how do hair protect against heat

its white which reflects light so less heat

how do stringing hairs work

outer layer is made from silica (glass material ) which is very brittle, so when it breaks it release poison

purpose of platelets

Defense against heat

plants covered by platelets aka silver berry, it shades the plants so it can grow in higher heat

Hairs on roots:

root hairs

root hair purpose

vital for water uptake

life span of root hairs

short lived

one or two weeks and then root need to grow more and new hair forms there

Conical epidermis

epidermis cells breaks ligh in different way which creates a nice sheen attracting insects

H2O-repellent epidermis

some leafs want to be kept dry as stoma are on top and if covered theres no gas exchaneg

h20 repeelant epidermis makes it so watwr cant touch the botton layer

Water and dirt repellent epidermis

in the lotus

h20 repellent and also pickes up dirt

Epidermal sensing hairs

in the venus fly trap

grows specilaized leaf not for photosynthesisi but to catch food

hairs responds to touch twice in 20 secs cuz it it touched once it could be dirt or anythig but life things move and would touch twice

Epidermal adaptations

Outer epidermis of the trap: helpful to climb up

Rim epidermis: directional, slippery grooves

Rim edge: downward pointing teeth and glands

Glands at the inner rim edge: Alluring sweet treat Slippery wax

Interior: slippery, overhanging epidermal cells (going down easy but up almost impossible )

Glands produce enzymes for insect digestion

unique epidermis

Conical epidermis

H2O-repellent epidermis
dirt repellent.

hair sensning

unique traits of the pitcher plant

function of periderm

protection and exchange

second most specialized

why is permiderm needed

Growth of stem → ripping-apart of epidermis

Needed: NEW sealing (beyond epidermis)!

where can perimederms be found

parennials

function of periderm in parrenials

like epidermis

what is the periderm made out of

Made up from two cell types:

● Cork cambium (meristem; source of new periderm)

● Cork cells (protection)

cork cambium

secondary meristem

not present in seedling but developes later on

Cork cells

dead at maturity,

walls with lignin (anti-microbial (hard for bacteria to get in))

suberin (wax-like (good for protecting cell), against desiccation)

function of xylem

(transport, support, storage)

what is the xylem

Continuous system transporting water and minerals from roots to rest of the plant

part of xylem

• Tracheids (transport, support)

• Vessel members (transport, support)

• Fibers (support)

• Parenchyma (storage)

which parts of xylem are dead at maruity and which are not and is this a bad thing

dead at maturity

• Tracheids (transport, support)

• Vessel members (transport, support)

• Fibers (support)

not dead

• Parenchyma (storage)

not a bad thing cuz they do their jobs even as dead

whta is used for tansport in xylem

tracheids and vessel membranes

are trahcied and vessels the same

same function but evolutionary very different

Tracheids vs. vessel shape

Tracheids:

• narrow, long

• tapered (pointy)

vessel shape

• wider, shorter

• flattened

Tracheids vs. vessel evolutionary

Tracheids:

• evolutionary old

• gymnosperms and angiosperms

vessel shape

• evolutionary newer

• angiosperms

Tracheids vs. vessel movemetn of water

Tracheids:

• water moves between tracheids only through pits

- H2O flows through adjacent pits from cell to cell

• less efficient water transport

vessel shape

• water moves from one vessel ement to the next through performations and pits

• more efficient water transpor

why are wallas of vessel and tracied lined with ligin

high force of water

which are stronger vessels or tracieds

vessels Generally more strongly enforced than tracheids (bc wider: need to withstand more water pressure)

what would the xylem in soft wood be made out of

tracheids

what would the xylem in hard wood be made out of

both trachieds and vessesl

how do xylem act as support

Most ± lignified = hard, sturdy

function of phloem

transport

what does the Phloem consist of

• Sieve tube members (transport) • Companion cells (“control center")

purpose of Phloem

Continuous system transporting dissolved primarily sugars from leaves to the rest of the plant

how does Phloem work

Sugar flows through sieve tube members, divided by sieve plates Companion cells: control both themselves and sieve tube members

Vascular tissue: non-woody plants

Vascular tissue: trees

function of Ground tissue

support, storage

Ground tissue (non-woody plants)

Tissues other than dermal and vascular tissue systems

what is ground tissue made out of

Ground tissue is made up by parenchyma >>> collenchyma >>>> sclerenchyma

use of ground tisse

Use: photosynthesis, store nutrients, fill space

1. When guard cells are well hydrated, they are much wider than high

true

Which complex tissue can be made up of the following components? Epidermal cells, cuticle, glands, hairs, stomata

epidermis

is epidermis alive or dead at maturity

alive

1. How many guard cells are there per stoma?

2

The outer wall of a guard cell is ____ compared to the ____ inner wall.

thinner

more enforced

When guard cells take up water and hence have to accommodate this higher volume, the outer walls of the two guard cells ___  and hence  become more ___ , while the inner walls become more __ . This turns the two guard cells into something like _, and thus _ the stoma.

expand

convex

concave

two curved sausage

opening

when do the outer walls of stoma become more convex

when the the outer walls of the two guard cells expand

when do the iner walls of stoma become more concave

when the the outer walls of the two guard cells expand

Which complex tissue can contain all of tracheids, vessel members, fibers and parenchyma cells?

xylem

1. In the following is a description of one part of the epidermis. Which one?

This cell type, being part of the epidermis, has various roles: on leaves, it can act to deter herbivory mechanically (insects do not like to mess with it) or even chemically (when it is full of toxic chemicals), it can shield a leaf from too much sun and when on roots, water and nutrients are taken up through it.

Trichome

Which complex tissue consists of two cell types only, of which one is a secondary meristem and the other is dead at maturity and the cell walls are enriched by suberin and lots of lignin?

Periderm

1. At what developmental stage does the periderm take over from the epidermis in its activity of sealing the stem?

In year 2

To which complex tissue is the periderm functionally analogous?

Epidermis

This cell type, as a part of the epidermis, is typically used uniquely for chemical warfare to deter herbivores. Which part of the epidermis is this?

Gland

Which member of the epidermal tissue produces THC?

Gland

1. Epidermal hairs only occur on above-ground plant organs

false

1. Which complex tissue is mostly made up of parenchyma cells, followed by some collenchyma and sometimes sclerenchyma?

Ground tissue