Untitled Flashcards Set

Challenges to overcoming world hunger
o Addition of 2 billion people to global population by 2050
o Need to produce 70% more food globally to support population increase
§ Boost productivity (genetic modification, selective breeding)
§ Increased land usage for agriculture
• Obtaining Nutrients
o Carbon dioxide, sunlight, and water are needed for photosynthesis
§ SHOOT (above ground portion = leaves and stems)
• Absorbs carbon dioxide and light energy (leaves)
§ ROOT (below ground portion)
• Absorbs water and nutrients
o Nitrogen and Phosphorus are limiting nutrients to plant growth
• Fertilizers & Eutrophication
o To increase plant productivity, fertilizers that contain high concentrations of nitrogen and
phosphorus are used to help plants grow more, produce larger fruit, and become
harvestable more quickly.
§ Overuse of fertilizers can cause Eutrophication
• Nitrogen and phosphorus that isn’t absorbed by crop plants runs oR into
rivers, lakes, and streams, fertilizing the water where algae (single-celled
plants) live
• The algae population explodes in size, and slowly die oR when nutrients are
used up (Harmful Algal Blooms)
• Bacterial decomposers use oxygen in the water to break down the dead algae
• Other organisms like fish, reptiles, amphibians, and mammals cannot
survive in water with no oxygen available for respiration or feeding, leads to
DEAD ZONES
• Edible Parts in Plants
o Leaves
§ Cabbage, lettuce, spinach
o Fruits
§ Tomatoes, peaches, cucumbers, wheat, peanuts, beans, peas, corn
o Flowers
§ Cauliflower, broccoli, artichokes
o Stems
§ Celery, asparagus, celery
o Roots
§ Carrots, radishes, sweet potatoes
• Flower Structure (Sexual Reproduction)
o Imperfect flowers – have individual male and female flowers found in diRerent locations on
the plant
§ Corn
• Tassel (male, produces pollen)
• Ear (female, produces ovules = kernels)

o Perfect Flowers – have male and female structures found in one flower (more common)
§ Male (STAMEN) – pollen bearing structures that contain sperm
• Filament – supports anther & makes accessible to pollinators
• Anther – structure that produces and releases pollen
§ Female (CARPEL) – egg-bearing structures
• Stigma – sticky “landing pad” where pollen attaches at pollination
• Style - tube that connects stigma and ovary
• Ovary – protective structure that contains ovules, where eggs are fertilized,
this tissue develops into fruit after fertilization
• Ovule – egg producing structure
• Pollination – the physical transfer of pollen to stigma so that fertilization of egg and sperm can
occur
o Involves pollen grain developing pollen tube to extend sperm cells to female egg in the
ovule.
• Double Fertilization – type of sexual reproduction only observed in angiosperms (flowering
plants)
o One sperm fuses with other cells in ovule to become endosperm.
§ Provides nutrients to developing embryo as seed develops before it sprouts
o The other sperm fuses with the egg and becomes the embryo, which will sprout into a new
seedling
• Controlling Pests
o Pesticides
o Genetic Engineering
§ Transgenic organisms (those that contain DNA or genes from other organisms)
• Bt corn
o Contains genes from a bacterium that makes it resistant to insect
pests
o Produces its own pesticide
§ Genomic Editing
• CRISPR
• Selective Breeding
o Artificial selection
o Cross breeding
o Radiation breeding
Chapter 25: Plant Physiology
• How do plants stand up?
o Roots – anchor plants and soil and allow for absorption of water and essential nutrients
and minerals
§ Nitrogen and phosphorus key essential nutrients
o Shoots – Grow vertically to absorb carbon dioxide and light energy needed for
photosynthetic processes
§ Leaves – absorbing components for photosynthesis
• Chloroplasts – sites of photosynthesis, found within tissues of leaves
§ Stems - supporting leaves
• Specialized Support Cells & Molecules
o Cell Wall
§ Rigid outer boundary of cells, made of cellulose

§ Lignin forms inner cell wall and can be found in xylem tissues
o Central Vacuole
§ Fluid-filled organelle responsible for maintaining turgor pressure
• Helps keep plant rigid and upright
• If turgor pressure is high
o Central vacuoles will be full of water, and the plant stands upright
• If turgor pressure is low
o Central vacuoles will have much less water, and the plant will be
wilted, or sad
o Stomata
§ Pores or openings found in leaves that regulate gas exchange for photosynthesis,
and allow for the evaporation of water through transpiration
o Cuticle
§ Waxy coating on leaves and stems that help prevent water loss
• Plant Vascular Systems
o Xylem – one-way flow of water up from roots to above ground tissues (leaves and stems)
§ Transpiration – loss of water from leaves by evaporation
• Powers the movements of water, and nutrients throughout plant (cohesion of
water)
• Regulated by stomata
o Phloem – two-way transport of sugar from photosynthesis from leaves to other tissues
(stems and roots)
• Plant Growth
o Primary Growth
§ Lengthening or elongating growth
§ Apical meristems (where new structures grow)
• Shoot apical meristem – lengthening of shoot system
• Root apical meristem – lengthening of root system
o Secondary Growth
§ Growing in diameter, or width (not observed in all plants)
§ Lateral meristems (where secondary growth occurs)
• Secondary xylem produces a new tree ring in the stem which can be used to
estimate the age of trees
• Specialized Survival Strategies
o Carnivorous plants
§ Venus fly trap (produces modified leaves in a spring loaded trap)
• Found in habitats where nutrients like nitrogen may be hard to access
• Digest insects and small animals to gain nutrients they cannot absorb from
soil
o Nitrogen-Fixation
§ Root Nodules with nitrogen fixing bacteria
• Convert inorganic nitrogen gas into ammonia that plants can use
o Symbiotic relationship
o Stomatal Closure
§ Some plants have adapted to extremely hot environments and are able to close
stomata during the hot hours of the day to prevent water loss due to evaporation
• May have evolved other successful ways to photosynthesize
o CAM plants (succulents and cacti)

o Seeds
§ Way plants disperse oRspring
§ Embryonic plant that is contained by protective structures
• Foliage Color Changes
o As season starts to transition from summer to fall, the days shorten and the amount of
sunlight decreases (less energy for photosynthesis)
§ Photosynthetic pigments stop being produced by plant cells, which allows the
leaves to drain of the following pigments (in order)
• Chlorophyll – dominant pigment produced by plants
• Xanthophyll – yellow reflecting pigment also produced by plants
• Carotene – orange reflecting pigment also produced by plants
• Phototropism – growth of the stem of a plant towards the light
o Driven by hormone, auxin (promotes cell elongation)
• Ethylene – plant hormone that is released from fruit that promote ripening
• Plant Defenses
o Waxy coatings – prevent predation from small animals and insects
o Spines – specialized leaves that deter predators
o Toxins or poisons – can kill or repel animals that try to eat them