plant responses Flashcards
why are chemicals so important in coordinating the growth if plants
multicellular and small sa:v so need coord
x appear to hve nervous systems
chemicals can be carriedin plant t.sys and move
why are some chemicals described as plant hormones
made in one place and carried through the t.system to another region where they have an effect
inv in control and coord of the plant
analogous to animal hormones
explain the importance of multifuntion hormones in a plant
one chemical can exert control in diff ways in diff parts of the plant, allowing for complex coord w/out production of huge amounts of diff chemicals
how are plant hormones used to control fruit ripening
ethene inv in natural fruit ripening, climacteric-banannas, tomatoes at desired time
cytokinins and gibberellins to delay
why is it commercially imp to control FR
ripe easily dam in t
1c ripe finite life b4 goes off
if t hard, unripe lees likely 2 dam and dx go off
name 4 plant hormones with commercial uses
ethene
cytokinins
auxins
gibberellins
describe the changes in ethene and co2 prod in tomato as it ripens
Ethene levels rise at rate of approximately 5 µl / kg h–1
from day 2 to day 4 (1); and then remain at a
steady level (1); carbon dioxide levels increase at a rate of approximately 15 ml / kg h–1
from day 2 to
day 4 (1); as ethene levels rise (1); as the ethene levels plateau, the carbon dioxide levels decrease
steadily (1) at a rate of around 5ml / kg h
–1
for 5 days(1)
why do cool conditions slow the rate of ripening even if ethene is present
ripening is as a result of enzyme controlled reactions
at lower temps reactions occur more slowly
so ripening occurs more slowly even w/ethene present
commercial use of cytokinins
prevent aging of ripened fruit and lettuces
micropropagation to control tissue dev
commercial use of GA
delay ripening and aging in fruit to improve size and shape, beer brewing to speed up malting process
commercial use of auxin
rooting powders, seedless fruit
commercial use of ethene
ripening, promote fruit dropping- cotton, walnuts, cherries
propagation
growing new plants from the cells of an original plant
microprpagation
large scale propagation
what happens if balance of diff plant hormones lost
interuptio of metabolism of whole plant, death
why must there be a balance between the diff plant hormones
to enable the plant to grow
commercial use for synthetic auxins
hormonal weedkillers
how do weeds interfere with crop plants
by competing for light, space, water and minerals
suggest what is happening in eth and co2 prod graph
b Initial rise in ethene levels triggers start of ripening process (1); many different reactions take place
to bring about fruit ripening (1); requires a lot of energy so respiration rates increase (1); and so
carbon dioxide levels increase dramatically reflecting increased cellular respiration (1); raised ethene
levels maintain ripening process (1); but reactions gradually slow down as aspects of ripening are
completed so demands on respiration are less so amount of carbon dioxide produced is reduced (1).
Link between metabolic increase in response
to ethene, reflected by increased levels of carbon dioxide must be included.
investigating the effects of hormones on plant growth
.
synergism and antagonism w/ examples
.
abiotic stress
.
give an example of an auxin
IAA, indoleacetic acid
what does the effect of auxin depend on
its conc and any interactions it has w/ other hormones
