Exam 3 Flashcards
(130 cards)
apical dominance
suppression of growth of lateral or axillary buds perhaps by auxin-like inhibitor
serescence
breakdown of cell components (in deciduous plants and conifers) influenced by ABA and ethylene
twining movement
occurs in stems when cells elongate to different extent
-tendril twining stimulated by contact
nastic movements
-non directional movements that don’t result in an organ being oriented toward or away from direction of stimuli
tropisms
permanent movements resulting from stimuli coming from one direction (positive or negative)
phototropism
-tulip exposed to light from 1 direction over several weeks
-auxin influences this
gravitropism
-response to gravity
-roots positively gravitropic, negatively phototrophic
statolith
-starch containing plastid that act as gravity sensor
-common in roots
-amycoplasts have possible role in gravitropism
clinostat
device to counter effects of gravity in plant
thigmotropism
-a response by plant or plant part to contact with a solid object (coiling or twining)
-coiling results from cells in contact becoming slightly shorter and those on opposite side elongate
chemotropism
-response to presence of chemical
turgor movements in plants
-result from changes in internal water pressures
-ex. barberry flower: stamens jerk inwards when in contact with pollinator to encourage pollen deposition
sleep movements
-circadian rhythm in plants
-turgor movements are involved along with external stimuli of light and temp
-turgor changes caused by movement of water into and out of cells at bases of leaves and leaflets
photoperiodism
-length of day is related to onset of flowering in many plants
critical daylight
12-14 hours for initiation of flowering
short day plants
-ex. poinsettia
-flower if day length is shorter than critical length
long day plants
-ex. spinach, wheat, potatoes
-flower if periods of light are longer than critical length
day neutral plants
-can flower anytime of year
phytochromes
-pigments that control photoperiodism
-p red or pr absorb red light
-p far red and per absorb far red light
-one form is changed to other when exposed to right wavelength of light
thermoperiodism
-predict date of harvest based on temp and growth rates
degree days
measure number of days that temp exceed a certain level and will cause plant to flower
dormancy
-period of growth inactivity in seeds, buds, bulbs, and other plant organs even when temp, water, or day length would typically cause plant growth
theophrastus
-classified 500 plants as trees, shrubs, and herbs
-leaf characteristics
carolus linnaeus
-binomial nomenclature
-father of modern taxonomy
-developed a system of classifying plants (based on number of stamens)