Materials Required: Plant growth regulator(s), measuring cylinder, volumetric flask, beaker(s), electronic balance, distilled water.

Procedure:

Preparation of growth regulator solution:

• The strength of growth regulators is calculated in ppm (parts per million). One ppm means 1.0 mg of chemical dissolved in one litre of water.

• After weighing the required quantity of growth regulator transfer it to a beaker and dissolve it with the small quantity of solvent.

• Auxins are soluble in alcohol or 0.1% NaOH. Gibberellins are soluble in absolute alcohol, while, cytokinins can be dissolved in 1-2 ml N/10 HCl.

• Abscisic acid is highly soluble in NaOH. Shake the beaker till the growth regulator/chemical is fully dissolved. Now transfer it into a volumetric flask and make the final volume with distilled water to one litre.

• For every use, one should prepare a fresh solution. The following formula is used for the conversion of hormonal strength.

1. I) Percent solution = ppm / 10,000

2. II) ppm solution = % x 10000

Precaution:

• First of all check the expiry date of the hormone powder.

• The weight should be taken precisely, preferably on an electronic balance.

• Proper solvent should be used to avoid precipitation.

• Hormones deteriorate under high temperatures, so store in a cool and dry place.

• Hormones are photosensitive; therefore they must be stored in dark or amber-colored bottles.

• Use hormonal solutions for the treatment of cuttings and lanolin paste for layers.

• Solutions should be prepared fresh. If required to store for some time use, refrigerators.

• The treated cuttings should be planted with the help of some stick to make a hole, so as to avoid the removal of the solution from the basal end of cutting.

Q.1 Calculate how much quantity of IBA is required to prepare 0.01% solution of IBA to treat bougainvillea cuttings