Lecture 11 RH Flashcards
What are some biotic stress factors that affect plants?
Weeds- endemic vs invasive (different categories)
Pests and diseases (flowering trees and seed bearing trees)
How are weeds controlled?
Biological: Includes using animals or other natural enemies to feed on the weeds.
Cultural: Farming systems
Physical: Mulching, hand removal
Chemical: Herbicides
What are some abiotic stress factors?
Drought
Floods
Salinity (evaporation of water from the soil could be problematic)
Low nutrient soils (Australia has a problem with mineral nutrients such as phosphorus and nitrogen)
Fire (Australia has severe fires in summer and autumn)
Why do some plants have mycorrhizal association?
Increases nutrient uptake
Fungus brings in usable nutrients to the plant
Plant breaks down fungus, and obtains nutrients
What are the factors affected by fire?
Physical properties
Chemical properties
Nutrients (decrease in potassium and calcium levels in the soil)
Soil temperature
Soil moisture
Soil biota
What are adaptations that plants have to regular fires?
Resprouters grow from burned trunks
Reseeders produce more trees. (Some seed testa are so rigid that fire is necessary for them to emerge)
How are resprouters adapted to fires?
Rapidly developing buds are formed (At the terminal and can either be naked or have accessories)
Bark produced (some buds form under bark stimulated by hormones during dry seasons)
Underground organs such as lignotubers and tubers
Resprouters use mycorrhizal associations
Other adaptations include scleromorphology adaptations
When does the red bean orchid flower?
After fires
What do naked buds do?
Stalked buds in leaf axils with 1 - 3 per axil.
These buds develop with terminal buds reestablishing canopy cover quickly.
What do accessory buds do?
Secondary buds formed near primary buds
What is the benefit of having bark?
Increases the thickness of the wood and charred bark is shed
What does bark contain that can be used by humans?
Oils (Eucalypts)
Tannins (eg Redwoods)
Sap
What are lignotubers?
Bulbous mass of buds:
Large woody stem swelling
Basal stem tuber bearing many buds
Embedded in bark
Above or below ground
What are tubers?
Underground storage organs and is deep in soild making it protected from fire.
They are normally used for asexual reproduction for regeneration and is dependent on time of fire.
Which trees typically form lignotubers?
Eucaypts (mostly Mallee eucalypts)
What is the function of lignotubers?
They persist throughout the life of plants and are important to fire response and environmental stress response
What is serotiny?
Cones can withstand wildfire. Extreme temperatures open cones and distribute seeds
What happens to leaf morphology in response to fires?
They become hard and rigid with short internodes.
Small plant size
Sclerenchyma tissue is abundant in leaves
What is the origin of scleromorphology?
Probably evolved on margins of rainforest communities in heath vegetation
What are some water conservation strategies for plants?
Small air spaces
Less stomata
Sunken stomata
Small vascular bundles
Fewer vascular bundles
Usually only mesophyll present (no palisade cells)
What is required for germination of new plants?
Testa rupture
Water uptake
What treatments can increase germination?
Temperature: Heat
Physical abrasion
Nutritional smoke water, mycorrhiza
What does burning vegetation do to stimulate seed germination?
Produces cyanohydrins that liberate cyanide and stimulate seed germination
What are the largest angiosperm families in Australia?
Fabaceae 12% (dicot Acacia)
Myrtaceae 9.3% (Dicot Corymbia)
Asteraceae 8.0% (Dicot Goodenia)
What are Casuarinaceae?
She-Oaks which form trees or shrubs
What do causuarinaceae leaves look like?
Reduced to fused teeth on stems
Number of teeth around the stem are diagnostic of
How are casuarinaceae geographically separated?
Northerly form casuarina
Southerly form Allocasuarina
How are casuarinaceae pollinated?
Wind pollination
What do casuarinaceae fruit look like?
Woody cone. Bracts become woody (fire resistant)
Seeds are released when desiccated
What type of flowers do casuarinaceae produce?
Males: 1 bract 2 scale like perianth parts and 1 stamen
Females: 1 bract, 2 bracteoles, ovary of 2 carpels, 2 long reddish styles
What are chenopodiaceae?
Saltbushes
What kind of habitat do chenopodeaceae live in?
Saline habitats, coastal vegetation
What kind of vegetation do chenopodiaceae have?
Shrubs or herbs
What are the vegetative characteristics of chenopodiaceae?
Leaves are simple, alternate or clustered, exstipulate
What do chenopodiaceae flowers look like?
5 persistent sepals (swelling at fruiting into wings or spines or fleshy)
5 stamens
Superior ovary
K(5) C0 A5 G(2_)
What do chenopodiaceae fruit look like?
Dry cluster of follicles
What type of flowers are hibbertia representative of?
Dilleniaceae
Where are dilleniaceae typically found?
Tropical forests
What kind of vegetation does dillenaceae have?
Small Shrubs
What kind of inflorescence do dillenaceae form?
Solitary, often axillary:
Bisexual
Actinomorphic
5 free sepals, 5 free petals, few-numerous stamens, free or partly fused at base, some staminoides
What is the floral formula of dillenaceae?
K5 C5 A10 G(2_)
What kind of fruit do dillenaceae form?
Cluster of follicles
Where are epacridaceae located?
Southern hemisphere
What do epacridaceae look like?
Similar to Ericaceae
Medium tall shrubs
Leaves are simple, hard, mucronate, and have parallel veins
What are the floral characteristics of epacridaceae?
5 sepals (free or fused)
5 petals (free or fused)
5 stamens
Superior ovary (4 - 5 carpels)
1 - 10 locules
Common formula K(5) C(5) A5 G(5_)
What do epacridaceae fruit look like?
Woody capsule or succulent drupe
What do mimosoideae look like?
Bipinnate (ferny when young)
Phyllodes or spines (some) when old
Where are Mimosoideae located?
South America, Australia, Africa
What are the floral characteristics of mimosoideae?
Prominent stamen
Tightly packed flowers
Globular head or spikes
Floral formula: K4-5 C4-5 Ainf G1_
What kind of fruit do Mimosoideae produce?
legumes (hard seeded)
What are faboideae?
Pea plants
What is the lamiaceae family?
Mint family
What do lamiaceae produce as vegetation?
Shrubs and herbs (aromatic)
Leaves are simple, opposite or whorled, extipulate
What are lamiaceae floral characteristics?
5 sepals (fused)
4 - 5 petals (fused)
corolla is tubular, deeply lobed, and often 2 lipped
2 or 4 stamens, epipetalous, sometimes pairs of unequal length
Superior ovary
K(5) C(5) A2 or 4 G(2_)
What kind of fruit do lamiaceae produce?
4 achene-like nutlets
What is a unique feature to lamiaceae?
Fruit have 4 fruitlets
What is a common feature of all myrtaceae?
Woody with essential oils
Aromatic foliage when crushed
Where are myrtaceae located?
Mainly the Southern Hemisphere (Endemic to Australia, New Guinea, Indonesia, Timor, and Philippines)
Which genus is in the Northern Hemisphere?
Myrtus
What kind of flowers do myrtaceae have?
Actinomorphic
Bisexual
4 - 5 sepals that are free
4 - 5 petals that are free
2 - 10 carpels that are united
What kind of fruit do myrtaceae produce?
Dry, capsules in Southern Australian genera
Fleshy, berries in Northern Australian genera
Where are eucalypts located?
South East Australia
Dominate forests
Confined mainly to higher rainfall coastal regions
What do flowers of myrtaceae look like?
Actinomorphic
Bisexual
4 - 5 sepals and petals that are usually free
Numerous stamens, 5 or 10
2 - 10 carpels, commonly 5, united
What kind of plants are myrtaceae?
All species are woody with essential oils
What do fruits of myrtaceae look like?
Dry, capsules in South Us
Fleshy, berries in North Aus
Why is it hard to identify eucalyptus using leaf morphology?
As seedlings they have opposite leaves and as adults they become alternating.
Leaf shape is variable
What type of bark do eucalyptus have?
Decorticating: Shedding exposes smooth trunk and is shed seasonally in scales/broad plates/strips/ribbons
Persistent: Retains bark, rough bark
What is a unique feature of eucalypt fruit?
The operculum forms a cup
What kind of fruit do eucalypts produce?
capsules (valves that open when seeds mature)
In Eucalyptus, the bark type that is a seeder rather than a resprouter is the?
Gum
Name some Myrtaceae genera:
Acmaena (lilly pilly)
Angophora (apple box)
Callistemon (bottle-brush)
Leptospermum (tea tree)
Melaleuca (paper bark)
Tristania (brush box)
What is the common name of melaleuca?
Paper barks
Honey myrtle
How many species are there of melaleuca?
~150
What do flowers look like in melaleuca?
Stamens in 5 bundles
What kind of flowers to callistemon have?
Flowers form masses on inflorescence and are terminal at the end of branches.
*Look like dandelions that are pink and going around the stem in a whorled fashion at several points
How are stamens arranged on callistemons compared to melaleuca?
Melaleuca have stamens that split at the end of the styles.
Callistemons have several stamens that don’t branch
*this has to be done on a microscope
What are spider families also known as?
proteaceae
What do flowers look like in proteaceae?
they look like cones and are found on spikes
4 petal-like tepals
4 stamens
1 long protruding carpel
What do banksia trees look like?
Woody shrubs
Leaf are serrated ararnged in spirals and whorls
Flowers produce lots of nectar
Flowers are arranged on spikes
What do rhamaceae flowers look like?
Clusters of true flowers subtended by bracts
4 - 5 sepals +-petals free, floral tube resemble tubular calyx.
inferior ovary
1 - 5 carpels
K(5) C(5) A5 G(-2)
What family are rutaceae?
Citrus family
What do rutaceae flowers look like?
4 - 5 sepals, free or fused
4 - 5 petals, free or fused (some Correa)
8 - 10 stamens in 2 whorls
5 - 5 carpels free at base fused at the top
Superior ovary
What do rutaceae fruit look like?
Drupes with leathery outside
Which Australian families are monocots?
Cyperaceae
Iridaceae
Junaceae
Xanthorrhoeaceae
What do cyperaceae flowers look like?
Actinomorphic or zygomorphic
1 bract, 1 lemma, 1 palea
1 - 3 stamens free
Ovary superior, 2 carpels, 1 locular, 1 ovule, 2 styles, 2 stigma
P0-6 A1-3 G0
What type of fruit do cyperaceae produce?
Dry caryopsis
What do iridaceae flowers look like?
Bisexual, actinomorphic or zygomorphic
6 tepals, free or fused, in 2 whorles of 3’s
3 stamens, on 1 side of style
Ovary inferior, 3 carpels, 3 locular
What do junaceae flowers look like?
6 tepals in 2 whorls of 3’s
3 - 6 stamens, epipetalous
Ovary superior
P3+3 A3+3 G1_
What type of fruit do junaceae produce?
Dry capsule
What do xanthoraceae flowers look like?
Actinomorphic, bisexual
6 tepals, free or fused, in 2 whorls of 3’s
6 stamens
Ovary is superior, 3 carpels, 1 -3 locular
What kind of fruit do xsanthoraceae produce?
Capsule or berry
