examen 3 ? o 4 Flashcards
origin of seedling shoot?
plumule
what are the 2 main functions of the shoot?
support and conduction
the plumule in the embryo has 3 parts:
cotyledon, hypocotyl and radicle
what’s a phytomere?
repeated units
contrast the two terms
leaf primordia and bud primordia
develops into leaves, develops into lateral shoot
están en orden con la pregunta
tunica
consists of the outermost layer, cells divide anticlinially
corpus
body of cells underneath the tunica, cells divde periniclinally
what are intercalary meristems?
meristematic region between 2 highly differentiated regions
where are the intercalary meristems
in elongating internodes
what cells interconnect differentiated regions for the rapid movement of food and water?
protoxylem and protophloem
what is a meristematic cap?
bulk of meristem responsible for stem thickening
explain “open” and “closed” vascular systems
open: capable of secondary growth
closed: not capable of secondary growth
which hormones decrease extendibility ?
ABA and ethylene
what hormones increase extendibility?
gibberellin and auxin
do tall or short plants result from exposure to ethylene?
short
do tall or short plants result from exposure to gibberellin?
tall
in what direction are most ions moving? what ions moved?
outside, Ca, Cl and malate
what is the function of the xylem?
conduct water
what is the function of the phloem
conduct food
does the phloem transport water?
yes
what part of the plant is tapped for obtaining maple syrup?
young xylem cells
what are the benefits for transpiration?
cooling the plant
why do leaf mesophyll cells need water for their plasmalemma?
to absorb CO2, carbonic acid
what are the two parts of stomatal transpiration?
evaporation from the mesophyll and diffusion through the stomata
stomata are less that 1% of leaf surface area, but what percent of the water loss occurs there?
90%
can photosynthesis occur with the stomata closed?
yes, by cellular respiration
what inside the guard cells changes when a stomata opens?
turgor pressure
what is the osmoticum
solute osmotically active
what two modifications of the guard cells increase the stomata (opening) diameter?
radial micellations and attachment to each other at the poles
as abscisic acid concentration increases, what happens to the stoma?
closes due to the turgor pressure
if plants lack ABA, what changes in their phenotype?
they dessicate
how does temperature effect and guard cells?
increases cell respiration, producing CO2
do guard cells have circadian rhythms?
yes
how is the rate of transpiration affected by whether the air is humid, or if the air is dry?
humid: no evaporation
dry: there is evaporation
what experimental evidence indicates xylem transports water?
the distribution of radioactive isotopes
why does the experiment with pigments (cut flower placed in pigmented water) eliminate the hypothesis of root pressure forcing the water up the shoot?
no root pressure ?
does the ‘CAT’ theory require living cells?
no
apoplastic
outside
symplastic
inside
how are the following 3 terms interrelated- root pressure, guttation and hydathodes
they keep plants regulate their water balance and mineral uptake
water absorption by roots of transpiring plants may be passive. what is the transpiration stream and why is it important?
continuous flow of water and mineral from root to leaves help regulate temperature
what elements can leave the leaf?
organic compounds produced through photosynthesis
phloem-mobile
elements that pass rapidly through the phloem
phloem-immobile
cannot be relocated (stays in the phloem)
examples of phloem-immobile:
Fe, Ca, Zn and Cu
transpiration stream
mesophyll to phloem
what’s an early experiment of ‘movement of subtances through the phloem’?
girdling (removal from a woody stem)
what atoms are 14C atoms?
isotopes (more radioactive neurons)
what cells do aphids penetrate with their mouth parts?
sieve tubes
how can aphids be used to detect phloem activity?
they are phloem feeders
why does the sugar move?
it is carried passively by water to a growing tissue or root
where does phloem loading occur?
sucrose produced in mesophyll cells by photosynthesis. leaves are transported to the veins, where it enters the sieve tubes
what cells are vital for transport?
removal of sucrose = increased water potential BUT it moves out
during the silurian period, land plants probably appeared. theres were ‘bryophytes’, what era was this?
carboniferous
lis the four eras and when each begins
- palaeozoic 570
- mesozoic 245
- cenozoic 10
what are the three principle tissue systems and their functions
- ground tissue
- dermal tissue
- desicate system
is secondary growth monophyletic or polyphyletic
polyphyletic
what type of xylem evolved first?
tracheids
why is xylem well preserved, but not phloem?
lignin
what conditions are needed for coal formation?
anaerobic
which two plant groups typically have only primary growth
monocots and herbaceous dicots
the axial system is to the
fusiform initials
the radial system is to the
ray initials
initials
produced inward, turns into xylem cells
derivatives
produced towards (outside), turns into phloem cells
the cambial zone is broadly described to include
cambial initials and cambial derivatives
when initials divide periclinally, they produce
derivatives of the cambial zone
when initials divide anticlinally, they produce
initials of the cambial zone
what hormone is involved in resumption of cambium activity after a dormancy period?
auxin
fascicular cambium
portion within the vascular bundles
interfascicular cambium
portion arising in the pith rays
fruits with lenticels
mango, apples and avocadoes
what separates bark from wood?
cork
what layer of cells separates the inner and outer bark layers
vascular cambium
heartwood
darker, non-conducting wood
sapwood
light, conducting wood
tyloses
a balloon-like outgrowth from a ray or axial parenchyma cell through the pit in a vessel wall and into the lumen of the vessel.
helical
1 leaf per node
distichous
1 leaf per node (one plane)
opposite
2 leaves per node
decussate
2 leaves per node, perpendicular
whorled
3+ leaves per node
simple
one blade per leaf
