chapter 39 Flashcards
what are plant hormones?
chemical signals that modify or control one or more specific physiological process within a plant
animal hormones are produced in ____ concentration while plant hormones are produced in ____ concentrations
large, low
animals can produce hormones in a specific location because
they have a circulatory system that can transport it
plants produce hormones all over because
they don’t have a circulatory system that can move it, they usually act locally.
auxins cause ____ in ____ concentrations
elongation, low
what happens when leaves fall?
auxin levels are sent back to main plant and recycled
why are do fruits start off tart?
they aren’t ready for germination so they don’t want animals to eat them yet
sweet banans
degrade me with your ethylene emissions
how do immobile plants adapt to environmental circumstances?
developmental and physiological mechanisms
what is gravitropism?
response to gravity
what is positive and negative gravitropism?
going down, growing up
what are statoliths and how do plants use them?
dense cytoplasmic components cause calcium and auxins to accumulate on the lower side of the root
what happens to elongation when auxins are at high concentration?
elongation is inhibited
what is thigmotropism?
movement or growth in response to touch, seen on vines and climbing plants
what is thigmomorphogenesis?
changes in morphology that result from a mechanical disturbance (trees that bend due to wind)
what is abiotic and biotic?
nonliving and living
how do xerophytes avoid drought and what are the consequences?
they are adapted to dry enviroments, minimize water loss but take in less CO2, they wont grow as big, they close their stomatas and have waxy cuticles to keep water in.
what are stomatal crypts?
depression in leaves
what are some root adaptions for dry environments?
shallow roots- take advantage of water to soak up immediately
main root-for deep penetration heh
what are alternative strageties to dry environments?
reduce SA of leaves, hang down to avoid sunlight, negative water potential
what are CAM plants?
photosynthesis and respiration occur opposite in hot environments
why are wet environments bad for plants?
can drown, not enough oxygen
what are adaptations for wet environments?
shallow, slow growing roots that carry out alcohol fermentation
pneumatophores-snorkels
what is a plants first line of defense against infection?
epidermis and periderm
how do pathogens enter?
wounds or natural openings like stomata
what are pathogen-associated molecular patterns?
molecular sequences are specific to certain pathogens, they sraer a chain of signaling events leading to production of antimicrobial chemicals and toughening of the cell wall with proteins
what is a ligin?
mechanical barrier and toxic precursor
what is the hypersensitive response?
causes cell and tissue death near infected site, induces production of enzymes that attack pathogen, stimulates changes in the cell wall that confine pathogen, LOCALIZED AND SPECIFIC! SHORT TERM
what is systemic acquired resistance?
causes systemic expression of defense genes and is a long lasting response NONSPECIFIC BUT LONG-LASTING
salicylic acid triggers?
the defense system to respond rapidly to another infection
what is herbivory?
animals eating plants
how do plants defend themselves against herbivory?
physical defenses like thrones and chemical defenses like tasting gross or toxins
what are secondary metabolites?
do not aid in the growth and development of plants but are required for the plant to survive in its environment
a molecular level defense, chemical defenses like cocaine or nicotine
what are trichomes?
a cellular level defense, structures that irritate organisms
what is a tissue-level defense?
leaves are toughened by tissue
what is an organ level defense?
leaves are modified into spines and bristles, stems turn into thornes
what is organismal level defenses?
plants may respond to attack by altering flowering time
what is population level defense?
some plants release chemicals in response to herbivore attack that trigger defense responses in nearby members of the population
what is community level defense?
some plants “recruit” predatory animals that help defend against specific herbivores (usually diff species)
