Understanding Plant Growth Regulators. What is a Plant Growth Regulator? Chemicals which affect the...
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- Slide 1
- Understanding Plant Growth Regulators
- Slide 2
- What is a Plant Growth Regulator? Chemicals which affect the
plant in many complex ways Cell division and differentiation, root
and shoot growth, flowering and ripening
- Slide 3
- 2 Types of Plant Growth Regulators Natural Made inside the
plant Low concentrations Five groups Auxins, cytokinins, ethylene,
gibberellins and abscisic acid Man-made/Synthetic Applied to plants
to obtain a wide variety of changes Makes the plant better or more
saleable!
- Slide 4
- Which grapes would you rather eat? The ones on the right were
treated with gibberellic acid to make them larger.
- Slide 5
- Naturally Made Plant Hormones
- Slide 6
- Auxins Produced by the tip, or apical meristem Stem cells
elongate and divide They also flow down from the tip of the stem,
preventing lateral buds blooming early
- Slide 7
- 3 Effects of Auxin on Plants 1. Auxin causes the tip of the
middle stem to grow at a faster rate This trunk should be a single
stem; however, the terminal bud was removed forcing it to
branch.
- Slide 8
- 2. Auxins are responsible for allowing a plant stem to grow
toward the sun The left side of the plant was exposed to the sun.
The right side had shade and grew faster.
- Slide 9
- 3. Auxins allow a plant to respond to the touch of a person or
other object
- Slide 10
- Cytokinins Responsible for cell division and differentiation
Produced in the root tips They tend to travel up the stem Effect is
Apical Dominance
- Slide 11
- Ethylene This is a gas that affects the plant like a hormone It
is produced in ripening fruit and dying plant material It
stimulates flowering in some plants and causes other fruits and
flowers to ripen more quickly and evenly
- Slide 12
- Effects of Ethylene Ripen fruits faster in a paper bag, than on
the counter On cut flowers & foliage will die In this
experiment, two holly twigs were placed under separate jars for a
week. At the same time, an apple was placed in the second jar. The
ethylene given off by the apple caused the holly to lose its leaves
and die.
- Slide 13
- Gibberellins Helps promotes growth and stem elongation for
trees Produced in the stems, roots and young leaves Effects are
flowering of plants early and breaking seed dormancy too soon
- Slide 14
- Abscisic Acid (ABS Acid) Found in dormant seeds and in dying
leaves Effects are inhibiting growth and induced bud dormancy Helps
a plant prepare its buds for winter The dormant bud on the left has
a high concentration of abscisic acid. As spring nears, the acid
level drops and the bud begins to develop a new shoot.
- Slide 15
- Synthetic Plant Growth Regulators Useful for commercial plant
crops They can save money, time, and can lead to a better crop Help
reduce size and make plant look shorter Root more completely Help
ripen faster
- Slide 16
- Assignment You and a partner will make up a poem/
song/riddle/ect about natural and synthetic plant growth
regulators. You must have the following: Auxins, cytokinins,
ethylene, ABS acid, and Gibberlines What they do to the plant Be
creative and appropriate You will present to the class your
poem/song/riddle