9. Write Short Note on Anti Transparent.
Ans.
Anti
transparent are the materials or chemicals which decrease the water loss from
plant leaves by reducing the size and number of stomata. Nearly 99 per
cent of the water absorbed by the plant is lost in transpiration. Anti transparent
and is any natural applied to transpiring plant surfaces for reducing water
loss from the plant. There are of four types.
1. Stomata closing
type:
Most
of the Tran spirants occur through the stomata on the leaf surface. Some
fungicides like phenyl mercuric acetate (PMA) and herbicides like atrazine in
low concentration serve as anti transparent by inducing stomata closing.
These might reduce the photosynthesis. PMA was found to decrease
transpiration than photosynthesis.
2. Film forming type:
Plastic
and waxy material which form a thin film on the leaf surface and result into
physical barrier. For exam pleethyl alcohol. It reduces photosynthesis.
Tag 9: S - 789 foliate.
3. Reflectance type:
They
are white materials which formacoating on the leaves and increase the leaf
reflectance (albedo). By reflecting the radiation, vapour pressure
gradient and thus reduce transpiration. Application of Spercent kaolin
spray reduces transpiration losses. eg. Diatomaceous earth product
(Celite), hydrated lime, calcium carbonate, magnesium carbonate, zines sulphate
etc.
4. Growth retardant:
These
chemicals reduce shoot growth and increase root growth and thus enable the
plants to resist drought. They may also induce stomata closure.
Cycocel is useful for improving water status of the plant.
Anti
transpiratnts are also useful for reducing transplantation shock of nursery
plants Examples / Different anti transparent:
(1) Metabolic
inhibiter like phenyl mercuric acetate, some alkanet succinct acids.
(2) Growth retardant
such as A. B. A. Cycocel.
(3) Herbicides,
fungicides
(4) Salicylic acid.
(5) Colorless
plastics, silicon oil, wax or plastic.
(6) White reflecting
materials (e. G. Kaolin) emulsions or white wash.
Good features of contra
spirant
(1) Non toxicity
(2) Non permanent
damage to stomata mechanism.
(3) Specific effects
on gard cells and not to other cells.
(4) Effect on stomata
should persist at least for one week.
(5) Chemical or
material should be cheap and readily available.
Role of anti transparent
in annual field crops:
In
general field crops are highly dependent or current photosynthesis for growth
and final yield. Therefore it is unlikely that currently available anti transparent
would increase yield of an annual crop unless crop suffers stressed from
inadequate water and or a very high evaporative demand, particularly during a moisture
sensitive stage of development.
Fuahring
(1973) sprayed stomata inhibiting or film forming anti - Tran spirants on field
grown • Sorghum under limited irrigation conditions, he found that grain yield
increases Sto 17% and application Ppt antitranspirant just before the boot
stage was more effective than later sprays.
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