Plant Physiology Flashcards

Terms Definitions
Transpiration
Movement of water in vascular plants due to pull of water by evapotranspiration through the stomata
Water Cohesion
When water molecules are attracted to the walls of the vascular tissue allowing for Bulk flow of water
Water Adhesion
When water is attracted to other adjacent water molecules along the vascular tissue
Pressure Flow Hypothesis
Allows for sugar movement from source to sink in vascular plants
Hyperaccumulators
Plants that can absorb certain nutrients from the environment without them being essential
sugar movement
is via “the Pressure Flow Hypothesis”
cellular respiration
is basis for plant metabolism
alpine pennycress
removed zinc and cadmium near the site of a zinc smelter
Hydroponics
soil-less culture
mustards
(Brassicacea) contain high amounts of S
halophytes
use Na; growing in areas where salinization through irrigation has crippled agricultural production
horsetails
incorporate silicon (Si) into their cell walls, making them indigestible for most herbivores
Atriplex nummularia
saltbush
necrosis
localized tissue death
chlorosis
yellowing of leaves; older leaves have more severe chlorosis because young leaves can “steal” magnesium from older leaves
nitrogen fixing plants
play important role in housing N-fixing bacteria in nodules
Rhizobium and Bradyrhizobium
invade legumes such as peas and soybeans
alder trees (Alnus rubra)
form nodules with N-fixing actinomycetes
K
requirement is much less than N requirement
K fertilizer
obtained from mining phosphate rock (“potash”)…a non-renewable resource
Saskatchewan
highest producer of potash in the world (1/3 world production)
Leaf
is a factory for transforming energy from the sun into useable energy
Aristotle
thought everything just came from the dirt
Jan Baptista van Helmont
a 5 year mission to watch a willow tree grow ; ; 74.4 kg heavier, but the dirt was only 57 g lighter
Joseph Priestley
accidently hit upon a method of restoring air that had been injured by the burning of candles
Jan Ingenhousz
showed that only in the presence of sunlight could air be restored; CO2 + H2O + Light energy (C H2O) + O2 ; suggested that the O2 resulted from the splitting of the CO2 molecule
C.B. van Neil
CO2 + H2S + Light energy (C H2O) + H2O + 2S ; proposing that water, not carbon dioxide was the source of the oxygen in photosynthesis by all green plants (even purple cabbages).
Robin Hill
showed that isolated chloroplasts were able to produce O2 in the absence of CO2; found the heavy isotope of oxygen they used in their water came back out as gas
F.F. Blackman
there were light reactions and dark reactions; the rate of the dark reactions increased up to a temperature of 30 C
RUBISCO
F.F. Blackman; world’s most abundant enzyme which traps that slippery CO2 and puts it into a Calvin cycle that fixes it
Melvin Calvin
made the ultimate discovery of the mechanism of photosynthesis
Rxns in chloroplast
Light rxn (thylakoid membrane) + Calvin Cycle (stroma)
Calvin Cycle
End products: NADP+ and ADP + P; Sugar
Light Reaction
End products: ATP and NADPH; Oxygen
Light harvesting antennae complex
Light reaction contains chlorophyll and carotenoid molecules (pigment molecules)
Non-cyclic photophosphorylation
Photosystem I and II; produces ATP and NADPH
Cyclic photophosphorylation
Photosystem I; produces ATP
C3 Plants
CO2 fixed to 3 C PGA; accompanied by photorespiration; efficient at normal CO2:O2 ratio but declines under dry conditions when stomata must be closed
C4 Plants
plants that fix C to organic acids resulting in a 4 C product; less nrg efficient than C3 plants; can survive extremely dry environments; high light intensities and high temperatures (i.e. corn)
Photorespiration
Consumes O2 and releases CO2
CAM Plants
well-adapted to dry conditions (include cacti and other succulents); use both C3 and C4 pathways, but there is a temporal separation rather than a spatial one (open stomata at night)
Auxin
plant hormone that caused the Darwin’s seedlings to bend
Agent Orange
powerful herbicide and defoliant containing trace amounts of dioxin, a toxic impurity suspected of causing serious health problems, including cancer and genetic damage, in some persons exposed to it and birth defects in their offspring: used by U.S. armed
kinetin
growth regulators called cytokinins; sped up cell division (in corn)
ethylene
tends to slow things down by comparison to auxin and cytokinins
abscisic acid
named in the 1960s when “all the leaves were brown.”
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