Experiences

Senescence of flowers

Mª Reyes Llácer Pérez

Spain

High Secondary School

Biology

Laboratory

Direct

Speaking of the internal environment of living things students are not able to understand the need to maintain the constancy of that medium. To better understand its importance they can practice studying senescence of flowers in different media.

The final stage of development of a plant or an organ is a senescent process than can be accelerated when the leaves or flowers are removed from the plant. Some substances can accelerate or reduce the entry into senescence process.
This experience uses daisies that have been recently cut with a stem of a minimum of 5 cm. Flowers are placed in water in individual tubes to which various compounds are added:
- 1 tube of running water.
- 1 tube of deionized water.
- 4 tubes at a dilution of vinegar that has different and increasing concentrations.
- 4 tubes with an aspirin solution having increasing concentrations in each tube.
- 4 tubes with a solution of salt having increasing concentrations in each tube.
- 4 tubes with a solution of bicarbonate which has increasing concentrations in each tube
- 4 tubes with a solution of sugar having increasing concentrations in each tube Therefore we will have 22 flowers in different solutions for the study. The observation was carried out over 2 weeks and the effect of different substances and concentrations in evolution of flowers (changing color, fading ...) is recorded. From the results we know that the senescence is accelerated in those tubes that have an acid, salt or basic medium. The daisies will keep better appearance when the medium provides them nutrients, although not at very high concentrations.

The practice may be interesting because students can draw conclusions that enable them to delay senescence in a bouquet of flowers and justify scientifically. It's a different way to study a natural phenomenon.