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Biol Unit 1
Biol Unit 2
biol 2 faq (nsfaq)
Biol Unit 3
Biol Unit 4
biol 4 faq (nsfaq)
biol 3 plant hormone summaries
In the space below you need to place your summary of plant hormones. It's up to you what you include but one example might be:
create a table that includes the names of the different hormones and one example of their site of production and subsequent effect
Try not to just copy info from another table. Ideally, you would create your own table by extracting information from the textbook or another source.
- Apical tip
- Young leaves
Elongation of cells- tropisms, apical dominance, growth of fruit.
- Young leaves
- Embryo in seeds
Promotes growth by stimulating cell division and cell elongation. Stimulates
(the first stage in the development of a plant from seed) and flowering.
Promotes cell reproduction and differentiation and hence growth. Breaks
(a delay in the growth of viable seeds because of unfavourable environmental conditions).
- Older leaves
- Root cap
Inhibits germination of seeds, promotes seed dormancy and seasonal dormancy. Causes abscission of leaves and fruit. Stimulates stomatal closure.
- Ripening fruit
Promotes fruit ripening, aging and abscission of leaves and flowers. Promotes germination.
Name of plant hormone
Role of plant hormone
-Plant growth regulator
-Promotes cell elongation
-It is responsible for the growing tips bending towards light source
-Promotes cell reproduction in growing tips, roots and fruit
-Promote cell elongation during growth in all plant tissues
-Encourage leaf drop
-Encourage dropping of ripe fruits
Involved in stomotal closure
Place of production
- Apical tip
- Young leaves
-Embyro in seeds
– are a type of plant hormone, of which indole acetic acid (IAA) is one. A major function of auxins is to control enlargement and elongation of cells. In stems and leaves of plants, auxins stimulate cell elongations, however may inhibit cell elongation in the roots of plants. Auxin is produced by the apical bud of a plant.
– also known as ethene, is secreted as a gas and promotes ripening of fruits and the abscission (shedding) of leaves through stimulating the formation of a protective layer referred to as an abscission layer, at the site of abscission. Ethylene is generally found/produced in ripening fruits, nodes of stems, aging leaves and flowers.
– a type of plant hormone which stimulates cell growth and cell reproduction. It is made in the roots and can act on them, but it can also act on shoots and fruits by moving up the xylem sap. An example of a common Cytokinins plant hormone is Zeatin.
– a class of plant hormones which stimulate cell growth and reproduction. Gibberellins also promote seed germination and flowering. (*Gibberellins promote cell growth by stimulating the synthesis of the enzyme amylase, a catalyst in the breakdown of starch. In breaking down starch molecules, glucose, a reactant in cellular respiration, is made available to the cell) An example of a gibberellins plant hormone is Gibberellic acid.
may inhibit germination of seeds, leading to seed dormancy and seasonal dormancy. Abscisic acid may also influence the opening and closure of stomata.
*This could be useful, you never know! Isn't funny how everything in Biology is so interrelated?!?
Interesting statement . Would be great if you could expand on it a little. That's one reason why I think life is so amazing! VM
Well, I was referring to extra info on gibberellins and how it helps produce an enzyme, which in turn breaks down starch, which then results in glucose being available, which is then used in cellular respiration to produce ATP. ATP is then used in basically everything - probably including the production of Gibberellins. It's like all interconnected.
Under the nautre of hormone column i had pictures of each of the plant hormones. Their structure, but it wont let me paste them there so you will all have you use ur imaginations. Sorry.. :)
Nature of hormone
Where is it found?
Transport in plant
embryo of seed
Tip to base through parenchyma cells
-stimulates cell elongation
-stimulates growth in flower plants
-stimulates fruit development
-stimulates ethylene synthesis
-stimulates the differentiation of phloem and xylem
-embryo in seeds
Xylem and phloem
-stimulates shoot elongation
-stimulates flowering and germination
-regulates production of enzymes in grains
-synthesised in roots
-transported to other organs
-stimulates cell reproduction by stimulating cell division
-involved in shoot growth
-delay leaf sequence
-stimulates the closure of the stomata
-inhibits germination of seeds
-promotes seed dormancy and seasonal dormancy
-causes abscission of leaves and fruits
-tissues of ripening fruits
-nodes of stems
-senescent leaves and flowers
Diffusion throughout intercellular spaces
-Stimulates fruit ripening
-senescence and abscission of leaves and flowers
It’s a naturally occurring hormone in plants
Produced in the leaves of the plant synthesised partially in the chloroplast
Transport can occur through both xylem and phloem tissues
Capable of moving both up and down the stem
Stimulates the closure of stomata (water stress causes increase synthesis).
Has an inhibitory effect on bud growth, which is utilised to ensure growth is not stimulated during periods of favourable conditions within inappropriate seasons when the plant will end up dying when conditions return to normal.
Has a positive effect on cell enlargement, bud formation and root initiation
Control the growth of stems, roots, flowers and fruits
Promotes the production of other hormones
Cause cells to increase in dark conditions and decrease in lighter conditions.
Affects the process of apical dominance by inhibiting the growth of buds situated lower down on the stem.
Produced by the growing part of the plant.
Influence cell division and cell formation
Assist in delaying the aging of tissues
Responsible for auxin transport within the plant
Counter the apical dominance induced by auxins
In conjunction with ethylene, promote ripening of fruit, leaves and flower parts
Is a gas that forms as a result of the breakdown of methionine produced in all cells
Does not accumulate within the calls but escapes from the plant via the process of diffusion.
It is produced at a faster rate in rapidly growing cells and in the dark.
Affects cell growth and shape by preventing cell elongation and causing the stem to swell. (Eg: resulting in the production of thicker and sturdier trunks and branches in response to external condition)
Production occurs when cells are more mature affecting fruit ripening as a climacteric event (released just before seen dispersal)
Large range of chemicals that are produces naturally within plants and by fungi
Play a major role in seed germination
Affects enzyme production mobilizing food production needed for plant growth by interfering with chromosome transcription.
Produced by the seedling during seed germination
Causes increase of internodal length
Promotes flowering, cell division and growth in seeds after germination
Reverses the inhibition of cell growth caused by abscisic acid
Auxin (eg. IAA)
Stimulates cell growth in stem; involved in phototropism
Produced in young leaves, roots and transported throughout plant
Stimulate cell division, as well as cell elongation during growth; break dormancy of seeds and buds
Usually found in plant seeds
Promote cell division, initate root, fruit or shoot development; promote cell expansion and growth of lateral buds
Found in high concentrations in growing plant tissues (eg. Young fruits) or in roots of mature plants
Growth inhibitor; germination of seeds, bud dormancy and dropping (abscission) of leaves or fruits; closure of stomata in leaves when water levels within plant are low
Produced in mature leaves and transported to other parts of a plant by way of phloem vessels
Ripening of fruit; healing of wounds; release of buds and seeds of some plants from dormancy
Accumulates in mature fruit and mature leaves
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