Download - Plant Hormones. Types of hormones Like animals, plants use hormones to produce functional and structural changes. Types of hormones include Auxins.

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Page 1: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

Plant HormonesPlant Hormones

Page 2: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

Types of hormonesTypes of hormones

Like animals, plants use hormones to Like animals, plants use hormones to produce functional and structural changes. produce functional and structural changes.

Types of hormones includeTypes of hormones include AuxinsAuxins GibberellinsGibberellins CytokininsCytokinins EthyleneEthylene

Page 3: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

AuxinAuxin

Auxins are a type of hormone that produces Auxins are a type of hormone that produces cell elongation and allows the plant to cell elongation and allows the plant to grow grow in length and to develop.in length and to develop.

The natural Auxin is a compound called The natural Auxin is a compound called indoleacetic acid or IAAindoleacetic acid or IAA

Page 4: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

AuxinAuxin

Page 5: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

Auxin associated with phototropism - early experimentsAuxin associated with phototropism - early experimentsdemonstrate tip as receptor.demonstrate tip as receptor.

Page 6: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

Auxin continuedAuxin continued

Auxin is made at the apical meristem of a Auxin is made at the apical meristem of a shoot and moves down at a rate of 10 mm shoot and moves down at a rate of 10 mm per hour to the region of elongation and per hour to the region of elongation and stimulates cell growth. stimulates cell growth.

Question???? At this speed, how do you think it is At this speed, how do you think it is

transported through the cell? transported through the cell?

Page 7: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

Auxin moves down the plantAuxin moves down the plantAnswer Too slow for phloem transportationToo slow for phloem transportation It is carried by the parenchyma tissue It is carried by the parenchyma tissue

from one cell to the next.from one cell to the next.

Auxins do two things to help with cell Auxins do two things to help with cell elongation: elongation:

1.1. Soften the cell walls so the plant can Soften the cell walls so the plant can expandexpand

2.2. Increase the rate of cell divisionIncrease the rate of cell division

Page 8: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

Demonstration of transported chemicalDemonstration of transported chemical

Page 9: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

Loosening of cell wallLoosening of cell wall

Page 10: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

Lateral growthLateral growth

Auxins produced in the meristem inhibits growth Auxins produced in the meristem inhibits growth of side branches (lateral stems)of side branches (lateral stems)

Page 11: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

CytokininsCytokinins

Page 12: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

CytokininsCytokinins

You will remember from Mor 4 that cytology You will remember from Mor 4 that cytology is the study of cells. is the study of cells.

The hormone, Cytokinins stimulate cell The hormone, Cytokinins stimulate cell division (mitosis and division (mitosis and cytokinesis)cytokinesis)

Cytokinins are produced by actively growing Cytokinins are produced by actively growing tissue and can move throughout the plant in tissue and can move throughout the plant in the xylem, phloem and parenchyma cells. the xylem, phloem and parenchyma cells.

Page 13: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

Function of cytokininsFunction of cytokinins

Promotes cell division.Promotes cell division.Lateral bud development.Lateral bud development.Delay of senescence (AGING).Delay of senescence (AGING).Stomata opening.Stomata opening.Rapid transport in xylem stream.Rapid transport in xylem stream.

Page 14: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

Cytokinins are used with Auxins to Cytokinins are used with Auxins to help plants to grow and develop help plants to grow and develop

Page 15: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

GibberellinGibberellin

Page 16: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

Effects of GibberellinsEffects of Gibberellins

General cell elongation.General cell elongation.Breaking of dormancy.Breaking of dormancy.Promotion of flowering.Promotion of flowering.

Page 17: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

GibberellinsGibberellins

Gibberellins are growth hormones that allow the Gibberellins are growth hormones that allow the plant to plant to grow in lengthgrow in length..

Gibberellins were discover in Asia when some Gibberellins were discover in Asia when some farmers noticed that rice would grow too fast and farmers noticed that rice would grow too fast and tall which was caused by a fungus called tall which was caused by a fungus called Gibberella. Gibberella.

Gibberellins are usually produced in roots and Gibberellins are usually produced in roots and young leaves and stimulate a growth in leaves and young leaves and stimulate a growth in leaves and stems but not in roots. stems but not in roots.

Gibberellins are also found to increase Gibberellins are also found to increase seed seed germination and flower developmentgermination and flower development

Page 18: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

Discovered in association with Foolish Discovered in association with Foolish disease of rice (disease of rice (Gibberella fujikuroi)Gibberella fujikuroi)

infecteduninfected

Page 19: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

Gibberellins and plant growthGibberellins and plant growth

Page 20: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

EthyleneEthylene

H H \ / C = C / \ H H

Page 21: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

Functions of ethyleneFunctions of ethylene

Gaseous in form.Gaseous in form.Rapid diffusion.Rapid diffusion.Affects adjacent individuals.Affects adjacent individuals.Senescence (Senescence (agingaging) and abscission () and abscission (the naturthe natur

al process by which leaves or other parts are al process by which leaves or other parts are shed from a plantshed from a plant).).

Interference with auxin transport.Interference with auxin transport. Initiation of stem elongation and bud Initiation of stem elongation and bud

development.development.

Page 22: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

Ethylene gasEthylene gas Years ago, farmers use to heat fruit in a Years ago, farmers use to heat fruit in a

kerosene oven to make them ripen faster. kerosene oven to make them ripen faster. Scientist learnt that it was not the heat but the Scientist learnt that it was not the heat but the ethylene gas byproduct that made it ripenethylene gas byproduct that made it ripen

We now know that plants develop their own We now know that plants develop their own ethylene as a hormone that makes fruit ripenethylene as a hormone that makes fruit ripen

Page 23: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

EthyleneEthylene Scientist also discovered that ethylene is the Scientist also discovered that ethylene is the

opposite to Auxin and opposite to Auxin and inhibits cell growthinhibits cell growth

Page 24: Plant Hormones. Types of hormones  Like animals, plants use hormones to produce functional and structural changes.  Types of hormones include  Auxins.

Thanks ClassThanks Class

Have a great day!!!Have a great day!!!