Living things and the processes of life
 The processes of life

Teacher/Technician Notes

These solutions may be available from a local secondary school or is available to order from SAPS -

0.417g calcium nitrate, (Ca(NO₃)₂) (oxidising agent)

0.2 g boric acid, (H₃BO₃)

0.101 g potassium nitrate, (KNO₃) (oxidising agent)

0.217 g magnesium sulphate, (MgSO₄.7H₂O)

3.5 cm³ 1.0M ammonium hydroxide, (NH₄OH)

Add these to some distilled water, dissolve, and make up to a volume of 1 litre with distilled water.

Safety

Wear eye protection and pvc gloves. Avoid raising dust when handling any of these chemicals

Nitrates - strong oxidising agents. Fire hazard is moderate by spontaneous chemical action. Can irritate the eyes and skin, causing burns. Decompose readily when exposed to heat, flame or shock.

Boric acid - Harmful to the skin & if swallowed. Irritant to skin, eyes and respiratory system

Ammonium hydroxide - Keep away from eyes.

Sugar Solution for Germination of Pollen Grains when using Mineral Salt Solution

1.2M sucrose (41g of sugar in 100 cm³ of distilled water)

Equal volumes of these two solutions should have a pH of 8.8.

Vary the ammonium hydroxide (NH₄OH) in the mineral salt solution to adjust the pH.

Sugar solution to be used on its own for the germination of pollen grains

Materials:

5 to 10 g sucrose, (10 g most commonly used successfully)
0.01 g yeast extract, such as Marmite
one small crystal of boric acid (Harmful to the skin & if swallowed. Irritant to skin, eyes and respiratory system)
100 cm³ water
1 g agar
pyrex beaker (250 cm³)
stirring rod
hot plate/microwave
microscope slides
flowers (sweet pea, hyacinth, laburnum, fuchsia)

Method:

• Add sucrose, yeast extract, boric acid crystal to 100 cm³ water in a pyrex beaker.

• Stir in the agar and warm over a hot plate or microwave gently to dissolve the agar.

• Spread a small amount of cooled agar onto a clean microscope slide and apply anther of chosen flower to release pollen grains.

• Place the slides on moist blotting paper in closed Petri dishes and incubate at 20^oC, (room temperature). Examine the slides after 30 minutes.

• Slides may be kept and examined for several days.

• If the stigma tips are placed on the slides near the pollen grains, chemical attraction will be seen.

The concentration of the sugar varies for different flowers, but 10% is suitable for most plants. Most pollen will germinate. Sweet pea, hyacinth, laburnum, and fuchsia are common plants which are available at different times of the year, and which have pollen that is capable of germinating on a slide. Welsh poppies germinate very quickly and easily using this method. The solution, without the addition of agar, can be placed on a slide using the hang drop method.

Calberla’s Solution can be made to the following formula:
5 cm³ glycerol
10 cm³ 95% ethanol (Highly flammable, vapour/ air mixtures can explode)
15 cm³ distilled water
2 drops saturated, aqueous solution of basic fuschin

To see the pollen properly they should be stained a light pink and not a dark red.
It may be necessary to alter the fuchsin concentration.