Viabilidade e longevidade dos grãos de pólen de Camellia sasanqua, Thunb.

Resumo

As a preliminary study on pollen of Camellia sasanqua, Thunb., several experiments were carried out to determine :

1. The best artificial culture medium

2. The viability and longevity of pollen grains

3. The storage capacity of the “Standard Medium”

As an artificial medium for pollen germination were used the following series :

Sucrose solution varying from 5.0 to 20.0%

Agar at 0.3 and 0.5%+ sucrose from 5.0 to 20.0%

Agar at 0.3% + sucrose at 5.0 and 10.0% + yeast

The viability and longevity of pollen grains were tested under the following conditions:

Flower detached from the plant at different stages of development.

Flower opened, detached from the plant, and kept at room and outside temperatures.

The addition of yeast to the standard medium was made according to the Brink's procedure. After protected against contamination and loss of moisture it was autoclaved for 40 minutes at 121º C. and kept in diffused light. The conclusions to be drawn from the above data are:

1. Agar at 0.3% + sucrose at 5.0 or 10.0% may be considered as good artificial culture medium for germination of Camellia sasanqua pollen grains (Tables I and II).

2. The addition of yeast to agar-sucrose substrate showed a stimulative effect on the germination of pollen grains.

3. Standard medium (agar 0.3% + sucrose 5.0% + yeast) showed to be the best one for germination and development of pollen tubes (Table III).

4. The growth-promoting power of the yeast was not affected by autoclaving the standard medium for 40 minutes at 121°C.

5. The best time to secure great amount of viable pollen is from the anthesis up to 24 hours later (Table IV).

6. When protected against the loss of moisture, detached flowers can be kept either in room or outside temperatures and will furnish viable pollen during 48 hours (Plate V)

7. Standard medium maintains entirely its pro- perties when stored during 4 days. The question of what will be its storage capacity beyond this period requires further investigation (Table VI).