This document discusses several types of plant growth regulators including morphactins, anti-transpirants, anti-auxins, anti-oxidants, and growth retardants. Morphactins are substances that modulate plant morphogenesis and include derivatives of fluorine compounds. Anti-transpirants help reduce water loss from plants and include stomatal closing agents like phenyl mercuric acetate as well as film-forming and reflective materials. Anti-auxins inhibit the effects of auxins and examples provided are TIBA, NPA, and clofibric acid. Anti-oxidants protect plant cells from free radical damage and include vitamins A, C, and E. Growth retardants like CCC reduce shoot growth
2. Morphactins
Morphactins are a group of substances which act on
morphogenesis and modulate the expression of
plants
Chemically, they are the derivates of fluorine
compounds
Fluorine - inactive, but the addition of COOH group
in the 9th position makes it active
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4. Effects of morphactins
Exhibit both synergistic and antagonistic effects-
depends upon the relative concentrations
They inhibit seed germination, sprouting, growth of
seedling and internode elongation
They depolarize cell division which probably leads to
distorted morphogenesis
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5. Contd….
Very effective in inducing lateral bud development, so
tillering will be profuse
Some morphactins stimulate flowering in certain short
day plants
Resemble ABA in inducing seed dormancy, bud
dormancy and suppressing stem elongation
Most of their effects can be reversed by GA3 treatment
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6. Applications
Morphactins + 2,4-D - controls weed growth
Morphactins + MH - suppress growth of grass in
lawns
Flurenol and chlorflurenol inhibits the opening of
stomata
Reduces transpiration in spinach and broad bean
(Rustagi, 2004)
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7. Okra
Pre-harvest application of 2.5 mg /lit chlorfluorenol-
methyl ester (CME ) induces anatomical changes
Including lower stomatal index and more long
trichomes
All of which could contribute to help water conservation
by the pods
Wax emulsion + 2.5 mg /lit. morphactin can prolonged
the shelf-life of pods
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8. Capsicum
A spray of morphactin at 1 ppm also significantly
increased fruit weight/plant, percentage dry weight
and titrable acidity
But reduced Calcium content in Capsicum annuum
cv. California Wonder
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(Asdoudi, 1993)
9. 2. Anti-auxins
These are chemicals which inhibit the action of auxins
They closely resembles auxin but lacks at least one
requirement for activity
Inhibit the effects of auxin
Synthetic chemical derived from α-p-choloro phenoxy
iso-butyric acid (PCIB)
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11. Contd….
Application of anti-auxins few days before harvesting
for leaf shedding in cotton
The anti-auxins TIBA, naphthyl-methyl-thiopropionic
acid and m-tolylpthalamic acid induce flower bud
formation in case of cauliflower
(Margara, 1977)
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12. Contd…
Application of HFCA (9-hydroxyfluorene-9-carboxylic acid)
and NPA (1-N-naphthylphthalamic acid) leads to
elongation of internodes in wild type of peas
Significantly reduced the endogenous levels of GA1
Below the application site IAA levels were also reduce
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13. 3. Anti-transpirants
The term anti-transpirant is used to designate
Any material applied to plants for the purpose of
retarding transpiration
Useful for reducing transplantation shock of nursery
plants (Horticultural plants)
Applied to transpiring plant surfaces for reducing water
loss from the plant
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14. Types of anti transpirants
1. Stomatal closing type :
Fungicides like phenyl mercuric acetate (PMA) and
herbicides like Atrazine in lower concentration serve as anti
transpirants by inducing stomatal closing
These reduce the photosynthesis
PMA was found to decrease transpiration than
photosynthesis
ABA induces closure of stomata
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15. 2. Film forming type
Plastic and waxy material which form a thin film on the
leaf surface
Results in reduction of transpiration rate and
photosynthesis
Examples: Silicone oils
Ethyl alcohol
Polyvinyl chloride
Polyethylene, polypropylene
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16. 3.Reflectance type
White materials which form a coating on the leaves and
increase the leaf reflectance (albedo)
Examples: Kaoline @ 5% spray reduces transpiration loss
Diatomaceous earth (Celite)
Hydrated lime,
Calcium carbonate,
Magnesium carbonate,
Zinc sulphate
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17. Features of anti-transpirants
Non toxic
Non permanent damage to stomata mechanism
Specific effects on guard cells but not to other cells
Effect on stomata should persist at least for one week
Chemical or material should be cheap and readily
available
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18. Phenyl mercuric acetate at 35 ppm, kaolinite at 5% were
sprayed on onion seedlings(Arka Pragathi, Arka Niketan, Arka
Kalyan and Pusa Red) 30, 50, 70 or 90 days after
transplanting and Irrigation was with held a week before
spraying
Anti-transpirants cause 27 to 40% stomatal closure and
reduction varied from 22 to 56% depend on cultivars
kaolinite treatment was most effective in reducing water
stress and stomatal closure
(Rao and Bhatt, 1990)
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Contd…
19. 4. Anti-oxidants
Antioxidants are nutrients in food that protect our cells
from damage by free radicals
Free radicals are unstable molecules that can damage
our cells
This cell damage may increase the risk of cancer, heart
disease, diabetes and infections
Free radicals may also affect brain function
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20. Types of Anti-oxidants
Vitamin A
Vitamin C
Vitamin E
Anthocyanins
Beta carotene
Catechins
Ellagic acid
Lutein
Lycopene
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21. Which Foods Have Antioxidants?
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pumpkin, winter squash Beta carotene
Beans Catechins, vitamin E
Beets Anthocyanins
Bell peppers Beta carotene, vitamin C
Broccoli, greens, spinach Beta carotene, lutein, vitamin C
Carrots Beta carotene
Tomatoes (canned) Lycopene, vitamin C
Sweet potatoes Beta carotene, vitamin C
22. Contd….
Ascorbic acid @ 50ml/L sprayed on brinjal had
significantly higher root weight, fruit yield, fruit free
total phenols, shoot and fruit potassium and calcium
contents under saline condition
Spraying of ascorbate is effective in alleviating adverse
effects of salinity
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(Shaban, 2007)
23. 5. Growth retardants
Chemicals which reduces shoot growth and increases
root growth
Enable the plants to resist drought conditions through
stomatal closure
CCC- Cycocel is useful for improving water status of
the plant
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