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80 Cards in this Set
- Front
- Back
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Features of the Myrtaceae family : poplar genus, leaf arrangement, floral formula
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-Eucalypstus, callistemon, melaleauca, leptospermon.
-leaves opposite/alternate -K4-5, C4-5, A infinte, G inferiror (2-10)(5), radially symmetrical, bisexual |
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The head of asteraceae flowers is known as a ... and it is composed of....
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Capitulm made up of sessile florets
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What is the Asteraceae floral formula?
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Kpappus, C(5) or (4), G(2 inferior), radially symmetrical, female or bi
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What is the Fabaceae floral formula?
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K(5), C3+(2), A10, G1, bi, asymmetrical
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What are some common genera of Lamiaceae?
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Thyme, rosemary, sage, mint
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Lamiaceae floral formula
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K(5), C(4-5) fused with A2-4, G loculi 4
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What is the floral strctre of the poaceae family?
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Bisexual florets, each enclosed by two bracts. Lower bract = lemma, upper bract = palea
Perianth absent Flowers arranged in spikelets |
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Orchidaceae floral formla
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K3, C3, A1 fused with G(3), bilaterally symmetrical.
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Which cell type is the plant equivalent of stem cells?
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Parenchyma cells
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Which cell has thickenings in the corners of it's cell walls?
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collenchyma cells
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What is the main water conducting cell in flowering plants?
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Vessel members
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What is the main water conducting cell type in gymnosperms?
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tracheids
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What is the main sugar conducting cell in flowering plants?
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sieve tube members
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What is the main sugar conducting cell in gymnosperms?
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sieve cells
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What cell type assists phloem loading in flowering plants?
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companion cells
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What cell type is responsible for photosynthesis?
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parenchyma
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What cell type is responsible for storage?
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parenchyma cells
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What are the four basic functions of roots?
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Anchorage
Absorption Conduction Storage |
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What is the layer of cells in the root stele between the vascular tissue and the endodermis?
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pericycle
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In secondary growth of roots, what happens to the endodermis and cortex?
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They are lost, in primary growth they are present.
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What is the vascular cyclinder in roots otherwise known as?
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The stele
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What is the function of the pericycle?
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To produce lateral roots
contributes to formation of vascular cambium (for secondary xylem and phloem) |
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What are the two main types of root associations?
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Mycorrhizae and rhizobium bacterial root nodules
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What are the two lateral meristems that give rise to secondary growth?
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Vascular cambium and cork cambium
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What are the two forms of vascular cambium?
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-Fusiform initials form the axial system (lengthwise)
-ray initials form the radial system (width) |
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How does photosynthate move from the phloem to the xylem?
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Through vascular rays; protoplast to protoplast
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What defines a dorsiventral leaf?
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differentiated palisade mesophyll
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What is kranz anatomy?
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The term used to describe the concentric circle layers of mesophyll and bundlesheath cells around vascular bundles in C4 plants.
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What surrounds the vascular bundles in C3 plants?
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mestome sheath
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What is one possible function of leaf hairs?
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Increased water absorbtion - empty shield cells fill with water. Water is drawn downwards by capillary action. (bromeliads)
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Why is it difficult to predict a specific response in relation to phytohormones?
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Because conditions change constantly .
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What often affects the effect of hormones?
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-presence or absence of other hormones
-the amount of hormone present -the sensitivity of the tissue |
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Describe auxin transport.
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It is polar (unidirectional), and basipetal (towards the base) in stems and leaves and acropetal in roots (towards root tips).
Movement is slow, 1cm per hour. |
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Some processes that auxin is involved in...
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-apical dominance
-promotion of cambial activity -vascular tissue differentiation -induction of adventitious roots -stimulation of fruit development -tropic responses -inhibition of abscission -stimulation of ethylene synthesis -inhibition or promotion of flowering |
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Through which cells does IAA (auxin) move?
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parenchyma cells of the cortex/vascular/pith
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Chemically what happens during auxin transportation?
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-pH 5 in cell wall - auxin picks up H+ (electrically neutral)
-diffuses across plasma membrane -pH 7 inside the cell loses H+, becomes negatively charged anion -auxin exits basal end of the cell through special carrier proteins |
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What role does IAA have in apical dominance?
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-basipetal flow from apical bud inhibits lateral/axillary buds
-as distance between shoot tip and axil increases, concentration of IAA decreases, allowing for axillary buds lower down to develop |
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What are two hormones that interact with IAA in apical dominance?
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-ethylene is produced by high concentrations of auxin which inhibits axillary bud growth
-cytokinins promote bud growth |
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Describe briefly how auxin promotes cambial activity.
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In spring when buds resume growth, the auxin produced in the apical regions moved downward in stems and stimulates cambial cells to divide into secondary vascular tissue.
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What does auxin do when a stem is wounded and vascular bundles are destroyed in herbaceous plants?
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Auxin stimulates the production of new vascular bundles from parenchyma cells in the pith.
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What does high auxin/gibberelin concentration promote?
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xylem differentiation
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What does low auxin/gibberelin concentration promote?
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phloem differentiation
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What impact does the percentage of sugars have on vascular tissue differentiation in relation to auxin?
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IAA+2% sucrose=xylem differentiation
IAA +3% sucrose = xylem and phloem differentiation IAA +4% sucrose = phloem differentiation |
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What hormone is in commercially available cutting rooting powder?
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IAA
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What hormone is produced by ovaries that promotes maturation of the ovary wall into a fruit?
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Auxin
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What does auxin do in terms of tropic response?
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Increase in the size of cells in order to respond to the tropism.
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What is the acid growth hypothesis?
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That IAA stimulates H+ into the cell wall, therefore lowering the pH. This activates pH dependant enzymes which results in the irreversible expansion of the cell wall.
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What is transported to the stem from fruits and buds to prevent abscission?
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Auxin
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During autumn, drought or nutrient deficiency, why does leaf/fruit abscission occur?
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Because there is a decrease in the auxin that is being produced in the shoot tips and fruits, resulting in abscission.
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What are two ways that IAA can be used in commercial farming practices?
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-In low concentrations to prevent preharvest fruit drop.
-In high concentrations to coordinate abscission in crops. |
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What are plants that are calcium deficient unresponsive to and why.
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IAA because IAA responses are dependant on calcium.
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What are the three steps in signal transduction?
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-Reception: the hormone binds to receptors in the plasma membrane
-Transduction: stimulates the production of a second messenger. -Induction: the secondary messenger activates a cellular response. |
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How many types of gibberellins are there?
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about 80 (most are inactive precursors for the active form)
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What does GA stand for?
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Gibberellic acid
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Which divisions/kingdoms do gibberellins occur in?
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Pterophyta, algaes, fungi, Bryophyta, Anthophyta, Gymnosperms
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In angiosperms, where does GA occur?
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immature seeds, root/shoot apices, young leaves
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What direction is gibberellin transport?
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All directions
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Gibberellin induces cell.... and cell....
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division and elongation
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Which hormone breaks seed dormancy?
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Gibberellin
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Which hormone induces the growth of juvenile leaves?
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Gibberellin
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Which hormone induces "bolting"?
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Gibberellin
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Where do cytokinins occur?
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Ferns, Fern allies, gymnosperms, angiosperms, bryophytes
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Where is cytokinin most likely produced?
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In the roots.
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When auxin is present, what does cytokinin do?
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Stimulates cell division
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What are cytokinins effects on cotyledons?
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-cell division and expansion
-increase in amount of sugars |
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Which hormones affect organogenesis?
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IAA and cytokinin
-low ratios favour shoot formation -high ratios favour root formation |
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Which hormone delays senescence?
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Cytokinin
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What effect does increased calcium levels in a cell have in relation to cytokinin?
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Increases the cell's sensitivity to cytokinin
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Which hormone is produced by insect larvae that induces the formation of galls?
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Cytokinin
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Where in the plant is ethylene formed?
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Everywhere, but especially the roots, shoot meristems, nodes, senescing flowers and ripening fruits.
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Which hormone inhibits cell expansion?
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ethylene
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Which hormone triggers fruit ripening?
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ethylene
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Which hormone inhibits flowering in most species other then mango/pineapple?
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ethylene
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What does ethylene do in waterlogged situations?
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Its production is reduced due to decrease in oxygen. Any that is produced is trapped in the roots and cell walls begins to breakdown. (production of intercellular spaces in hydrophytes)
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Which hormone increases the production of root hairs?
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ehtylene
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Which hormone promotes abscission in fruits/flowers/leaves/wounded organs?
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ethylene
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In what does absicic acid move?
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in the xylem, phloem and parenchyma
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Which hormone promotes/induces seed dormancy?
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abscic acid
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Which hormone is involved in opening/closing stomata?
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abscic acid
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Which hormone inhibits the effects of the other hormones?
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abscic acid
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