Transcript Basically Botany - This area is password protected

Basically
Botany
‘Starter’ Plants
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Stinkwood
Pepperwood
Rangiora
Crown fern…
Parts of a Plant
Pollination
Wind vs Insect Pollinated Flowers
Fuchsia Flowers
Fuchsia hybrida
Fuchsia excorticata
The flowers are very decorative; they have a pendulous "teardrop" shape and are
displayed in profusion throughout the summer and autumn, and all year in tropical
species. They have four long, slender sepals and four shorter, broader petals; in many
species the sepals are bright red and the petals purple (colours that attract the
hummingbirds that pollinate them), but the colours can vary from white to dark red,
purple-blue, and orange. A few have yellowish tones, and recent hybrids have added
the colour white in various combinations. The ovary is inferior and the fruit is a small
(5–25 mm) dark reddish green, deep red, or deep purple, edible berry, containing
numerous very small seeds. Many people describe the fruit as having a subtle grape
flavour spiced with black pepper.
Seed Dispersal
• Why?
– Plants spread their seeds to minimise competition (eg for
water) amongst seedlings
– And to reduce the chance of the whole species being wiped out
by a disaster.
• How?
– Water: floating seeds transported by streams, ocean currents.
Eg coconut, kowhai
– Explosion: seed pods rapidly open and fling seeds out. Eg
broom, gorse
– Wind: small light seeds, with structures that catch the wind are
transported downwind. Eg dandelion, thistle
– Eaten by animal: fleshy tasty fruit eaten and animal egests
seed out in a new location. Eg apple, apricot
– Caught on animal: seeds have hooks, catch on fur, fall off in
new place. Eg bidibid
Kowhai
Thistledown (aka fairy)
Dandelion
bidibid
Poor mans orchid
Seed Structure & Germination
External Leaf Adaptations for Photosynthesis
Structure
Wide blade
Thin leaf
Vein network
Green colour
Pores in leaf
Waxy surface
Strong petiole
Function
Leaf Cross Section
Key: 1) cuticle 2) upper epidermis 3) palisade mesophyll 4) spongy mesophyll 5) lower
epidermis 6) stoma 7) guard cells 8) xylem 9) phloem 10) vascular bundle
Internal Leaf Adaptations for Photosynthesis
Air space - intercellular gaps within the spongy mesophyll.
These gaps are filled with gas that the plant uses (carbon
dioxide - CO2 ) and gases that the plant is expelling (oxygen O2, and water vapour).
Cuticle - the waxy, water-repelling layer on the top and
bottom surfaces of a leaf; it helps keep the leaf from dying
out (and protects it from invading bacteria, insects, and
fungi). The cuticle is secreted by the epidermis. Label the
cuticle on the top and bottom of the leaf.
Guard cell - one of a pair of sausage-shaped cells that
surround a stoma (a pore in a leaf). Guard cells change shape
(as light and humidity change), causing the stoma to open
and close.
Lower epidermis - the waxy skin (outermost cells) on the
underside of a leaf, usually one cell thick; it keeps the leaf
from drying out.
Mesophyll - the chlorophyll-containing leaf tissue located
between the upper and lower epidermis. These cells convert
sunlight into usable chemical energy for the plant.
Palisade mesophyll - a layer of elongated cells located under
the upper epidermis. These cells contain most of the leaf's
chlorophyll, converting sunlight into usable chemical energy
for the plant.
Spongy mesophyll - the layer below the palisade mesophyll;
it has irregularly-shaped cells with many air spaces between
the cells, this allows gases to circulate. These cells contain
some chlorophyll (less light gets to here). The spongy
mesophyll cells communicate with the guard cells (stomata),
causing them to open or close, depending on the
concentration of gases.
Stoma - (plural stomata) a pore (or opening) in a leaf where
water vapour and other gases leave and enter the plant.
Stomata are formed by two guard cells that regulate the
opening and closing of the pore. Generally, many more
stomata are on the bottom of a leaf than on the top.
Upper epidermis - the protective, outer layer of cells on the
upper surface of a leaf, usually one cell thick. The epidermis
secretes the waxy cuticle which reduces water loss. The
upper epidermis contains some guard cells (but fewer than
the lower epidermis).
Vein (vascular bundle) - Veins provide support for the leaf
and transport both water and minerals (via xylem tubes) and
food energy (via phloem tubes) through the leaf and on to
the rest of the plant.
Xylem & Phloem
Both are transport tissues
Xylem
• Transports water, micronutrients from roots up to rest
of plant
• Forms woody layer in woody plants
• Mostly dead cells
Phloem
• Transports sugars, metabolic products from leaves
down to rest of plant
• Living cells
Multiple cross sections of a flowering plant
stem showing primary and secondary xylem
and phloem
Phloem / Xylem Celery Experiment
phloem
*Ringbarking aka girdling
•
Because phloem tubes sit on the outside of
the xylem in most plants, a tree or other
plant can be effectively killed by stripping
away the bark in a ring on the trunk or
stem. With the phloem destroyed,
nutrients cannot reach the roots, and the
tree/plant will die. Trees located in areas
with animals such as beavers are
vulnerable since beavers chew off the bark
at a fairly precise height. This process is
known as girdling, and can be used for
agricultural purposes. For example,
enormous fruits and vegetables seen at
fairs and carnivals are produced via
girdling. A farmer would place a girdle at
the base of a large branch, and remove all
but one fruit/vegetable from that branch.
Thus, all the sugars manufactured by leaves
on that branch have no sinks to go to but
the one fruit/vegetable, which thus
expands to many times normal size.
Photosynthesis
Plant Pigment Chromotography
Respiration
Transpiration
*Asexual & Sexual Reproduction