Lifecycle Adaptations Flashcards
What is the lifecycle of a plant?
Seed (embryonic)
Juvenile
Adult
Senescence
Death
Explain Seed stage?
Growth suspended till right environmental conditions are met.
Little metabolic activity
Low respiration
Low moisture content
How do seeds affect biodiversity?
Easy to spread plant population
May become dominant in area, influencing insect populations
May become invasive
How does this affect plant design in gardens?
Value linked to life cycle groups (perennial vs. annual)
How does it spread? rhizome/seed?
Genetically different which is good.
What is the Juvenile stage?
Produces only vegetative growth (unable to flower or reproduce)
How is juvenile stage affect biodiversity?
No chance to reproduce but great cover crops.
Cutting of juvenile root better.
Great for winter protection/layering
Examples:
Hedera helix, Cornus alba, Fagus sylvatica.
What is the adult stage?
Flowering and Sexual reproduction
What is senescence
Metabolism slows
Entire plant/fruit die back
Produces seedheads
What are the plant classifications according to their lifecycles?
Ephemeral (Taraxacum officinale or Stellaria media): Quickly colonize, quick to smother.
Annuals: Eschscholzia californica, Calendula officinalis) Enhance color and good for pollinators.
Hardy Annual: Withstand frost to 10c. Seeds sown in ground in autumn, germinate in Feb/Mar: Nigella damascena, Helianthus annus)
Half Hardy Annual: Withstand -5C. Sown under glass (mar/apr). Outdoors after frost: Cosmos bipinnatus, Nemesia caerulea
Biennials: Year 1 roots; Year 2 flower; Daucus carota, Digitalis purpuea
Tender Biennial: Oenothera biennis.
Perennials: complete life cycle more than 2 years. Flowers short lived; Phlox paniculate cv.
What is a herbaceous perennial
Does not form woody stems
Dies in fall new growth spring
Echinacea purpurea cv. Rudbeckia fulgida var. deamii
Tender perennial Heliotropium arborescens.
Example of evergreen herbaceous perennials
Long lived, non woody.
Provide winter presence.
Armeria maritima, Helleborus x hybridus cv.
Examples of woody perennials
TREE: Quercus robur, Fagus sylvatica
Shurb: Skimmia japonica, Buddleja davidii
Subshrub: Thymus vulgaris, Salvia rosmarinus
What should you be aware of when planting a woody perennial?
Long term investment:
Site selection, water and sun requirements essential.
Provides shelter for wildlife, privacy, decoration and area division.
Examples of perennials
Half Hardy: Heliotropium arborescens
Hardy: Achillea millefolium
Semi EG: Liqustrum vulgare or Quercus turneri
DESCRIBE BULBS
Herbaceous perennials
Swollen storage organs
Fleshy leaves in concentric rings attached to basal plate
Monocots
Allium validum, Narcissus papyraceus, Tulipa ianata ‘Regal’.
Describe Corms
Enlarged underground stems that store nutrients
surrounded by papery outer layers
Cormlets attached at bottom.
Crocus sativa, Gladiolus palustrus
Describe Tubers
Swollen stems or root enlarged storage.
stem tubers can start new plant.
root tubers need to be divided but do not grow new plants, just separated.
STEM TUBER: Solanum tuberosum
TUBER: Dahlia ‘Bishop of Llandaff’
What is a rhizome?
Swollen underground stem
Continuously grow horizontal above or at ground level
Bambusa vulgaris, Zingiber officinale, Iris pseudacorus.
What is an ecological niche?
Describes how a species interacts with and lives in its habitat.
Specific characteristics:
1. Dictates how it will survive
a. availabilty of nutrients, temp, sunlight, predators, and terrain.
b. impact of species on its enviornment as well as species requirements.
What is the competitive exclusion principle?
Two species can’t occupy same eco niche if competing for same resources.
Natural selection: if successful it reduces competition
If neither evolves to reduce competition, species that more efficiently exploits the resources wins.
What are the 10 plant survivability climates?
6 Natural
Mesophytes: Temperate
Xerophytes: Arid
Hydrophytic Freshwater aquatic
Cryophytes Arctic
Halophytes Coastal
Epiphytes Grown on other plants
Manmade:
Greenhouse
Fern House
Cacti and succulents
Alpine House
Details of mesophytes
Temperate climate
Modest range of req: Water, air, light, warmth plus few chemicals
Lives in high density with others
competes for nutrients
Leucanthemum vulgare
Centaurea cyanus
Details of xerophytes
Reduced leaf surface, hair or thick cuticles.
Store water in swollen stems, roots or leaves
Agave americana, Delosperma cooperi
Explain hydrophytic
Freshwater aquatic
Light absorbtion, lack of O2, C02 are problems.
Large leaf and stomata in upper leaf epidermis
Ceratophyllum demersum
Explain cryophytes
Arctic conditions
Lack of available water
Free draining soil and icy winds
Low compact form
Lewisia cotyledon, xCuprocyparis leylandii
Explain halophytes
Coastal conditions
Drying winds and salt
narrow leaves
waxy cuticles
Phlomis fruitcosa
Explain epiphytes
derives moisture and nutrients from air, rain
Orchids
What is required to manipulate plant growth?
Light: Quantity, Quality (blue veg; red/blue flowers) and Duration (CA poppy spring; sunflower Fall)
Temperature: Speeds or slows growth (with light, changed from veg to repro)
C02: Increases photosynthesis for growth
What does Temp affect in plants?
GERMINATION: certain temp germinates: cool season Lathryus odoratus: warm season (Solanum lycopersicum)
FLOWERING: Temp in combination with day length manipulates flowering:
EX: 12+ flowers of darkness untl flower buds form.
IF temp too high and days long plants will bolt (lettuce). If too cool fruit will not set on warm season crops (Tomatoes)
If erratic or water stressed - get cultivars that offer some resistance ‘bolt hardy”
What is breaking dormancy
Some plants need a certain number of days of low temp to break dormancy. They require time to “rest” b4 germination.
Look for # hours of plant like fruit and buy accordingly.
Plants can be “Forced” in a greenhouse.
Define abscission
Natural detachment of leaves from a stem. A layer forms over and leaf falls where petiole joins stem.
Why might a N deficiency occur?
an imbalance in C:N ratio within the soil
waterlogging/leaching of N
Low levels of OM
Reduced soil bacteria activity due to abiotic factors
Competition from other plants
Container grown - N depletion from other plants.
What are the stages of IPM?
Identify and monitor
Determine Action thresholds
Cultural (Prevention - encourage beneficials)
Physical (hand removal)
Biological (add ladybugs or nematodes)
Chemical
What is a biotic factor?
Living things within an ecosystem.
pollinators.
How does human activity affect N cycle?
synthetic fertilizers: Excess N lead to pollution of water bodies and contribute to eutrophication and greenhouse gas emissions.
Define eutrophication
N (fertilizer) runoff from the land, which causes a dense growth of plant life and death of animal life from lack of oxygen.
NPK
Nitrogen, phosphorous, potassium
NITROGEN: Leafy green
PHOSPHOROUS: Roots
POTASSIUM: FRUITS
Describe the Nitrogen Cycle (Tom)
Nitrogen gas exists in both organic and inorganic forms.
Organic nitrogen exists in living organisms, and they get passed through the food chain by the consumption of other living organisms.
Nitrogen fixation - atmospheric nitrogen (N2) which is primarily
available in an inert form, is converted into the usable form -ammonia (NH3).
- Nitrification - ammonia is converted into nitrate by the presence of bacteria in the soil.
- Denitrification - nitrogen compounds make their way back into the atmosphere by converting nitrate (NO3-) into gaseous nitrogen (N).
- Decay
- Putrefaction
Describe the annual lifecycle of a typical herb. perr.
Growth in spring from buds at, or near soil surface, stems and leaves grow and then, at some point in the summer, flowers are produced, followed by seed.
In the autumn the plants begin to die back and all above ground life ceases soon after the first hard frosts.
During the winter plants are dormant.
In some cases, plants are dormant in summer - depends on when they are most stressed.
2 differences between shrubs and trees
- Trees tend to be taller.
- Trees have single stem branching at height;
Shrubs have multiple stems which continually regenerate from the base of the plant.
What are 2 advantages of growing annuals?
Long summer flowering season
Feed pollinators
Wide range of colours
Cheap, fast and easy
What are implications of combining plants with different lifespans on the maintenance of a garden.
Some species need minimal care (Shrubs - Skimmia japonica)
Some need an annual cutback and tidy up.
Others (annuals/biennials) need to be resown or replanted every year.
How is water important to plants?
Responsible for turgor
Maintains cell shape and ensures cell growth
Solvent for minerals and carbo moving thru the plant
Resp for cooling leaves (TRANSP)
Regulates stomatal opening and closing (controls photo and trans)
Source of pressure to move roots thru soil
Medium in which most biochemical reactions take place.
What is relative humidity and how does it affect plants?
the amount of water vapor in the air relative to the maximum amount of water vapor that the air can hold at a certain temperature.
Relative humidity levels affect when and how plants open the stomata.
Plants use stomata to transpire, or “breathe.” When the weather is warm, a plant may close its stomata to reduce water losses. The stomata also act as a cooling mechanism.
When ambient conditions are too warm for a plant and it closes its stomata for too long to conserve water, it has no way to move carbon dioxide and oxygen molecules, slowly causing the plant to suffocate on water vapor and its own transpired gases.
As plants transpire, the humidity around saturates leaves with water vapor. When relative humidity levels are too high or there is a lack of air circulation, a plant cannot make water evaporate (part of the transpiration process) or draw nutrients from the soil. When this occurs for a prolonged period, a plant eventually rots.
When surrounded by warm temperatures in low relative humidity levels, transpiration rates in a plant increase, increasing the need for a grower to water and fertilize it.
To support cuttings and young plants, growers often use plastic tents or propagation chambers that increase relative humidity levels surrounding the leaves and ensure proper air circulation.
When conditions are too humid, it may promote the growth of mold and bacteria that cause plants to die and crops to fail, as well as conditions like root or crown rot. Humid conditions also invite the presence of pests, such as fungus gnats, whose larva feed on plant roots and thrive in moist soil.
What are the elements for plant nutrition?
3 found in air: C, H, O
6 MACRO: N, P, K, Ca, Mg, S
8 MICRO: Boron (B), Chloride Cl; Cu, Fe, Manganese Mn, Molybdenum Mo, Nickel Ni, Zn
What and when do plants absorb nutrients?
Roots: P
Leaves: N
Flowers; K
Dormant: few absorbed
Stressed plants reduce absorption.
How to improve Biodiversity?
Use plant lifecycles to encourage natural predators/parasites.
Grow wide range of plants for shelter
Install pond and nesting boxes
Companion planting: Calendula officinalis, Tagetes patula
Ladybeetles emerge from soil, feed on aphids
Naturalistic planting schemes for persistence thru seasons
Longetivity of flower and open,nectar rich, seed head
Hollow stems provide winter protection
Prune Feb/Mar.
What is climate change?
Increased variability of weather patterns.
Increased extreme weather
Desertification and more frequent droughts.
Changes to timing of the seasons.
HOw does climate change affect pollinators?
May expand range - more food needed.
Plants flower earlier
Pollinators emerge earlier
WORST: Change to timing of seasons result in miss-synchronization between flower and poll emergence - relied on for reproduction.
PLANTS time their flowering from a specific increase in day length, not temp.
More at risk are specific pollinators - not general.
If nectar source dries up entire plant and pollinators will be damaged.
What are the thermogenic issues?
Benefit maybe short term as colonizing more northerly, but may suffer due to habitat changes.
May allow exotic pests to colonize northern latitutdes…affecting bee industry.
Wetter summers, less flying days.
Bees rely on calm weather to reproduce. Also reduced viability of Queen Bee - issues with winter survival then.
Increased wet winters leads to increase mortality of ground hibernating species as waterlogged.
How does climate chnage affect migratory pollinators?
Disruption of air currents
Extreme N/S ranges may be affected by rising sea level.
What are some of the impacts on plant lifecycles?
Herb. Perr. may remain green over winter. PENSTEMON.
Could impact “chilling hours” required for flower buds. (Malus spp. or Vaccinium sp)
Temp changes on seed germination.
