EXPERIMENTAL: AN INVESTIGATION INTO SOME OF THE VARIABLES INVOLVED IN 
THE GERMINATION OF SEEDS

Introduction
The development, dispersal, and germination of seeds represents part of
the complex structures and mechanisms by which flowering plants ensure
successful reproduction; this is important, because the only purpose of
these living organisms is to ensure that some or all of their genes are
passed onto future generations.  Furthermore, as producers, flowering 
plants provide - via photosynthesis - the chemical energy required by 
consumers and decomposers:
              Light / Chlorophylls / Enzymes
6CO2(g) + 6H2O(l) ———————————————————————® C6H12O6(aq) + 6O2(g)     +DE

Seeds vary enormously in size and internal structure. Nevertheless, the 
structure of a typical seed is as follows: an embryo, consisting of a 
young shoot (the plumule), a young root (the radicle), and one or more
seed leaves (the cotyledons), surrounded by a seed coat (the testa).

Careful experiments have established that, for successful germination,
seeds have three requirements: water (to allow diffusion); dioxygen (to 
ensure that enough energy, in the form of ATP, is released via aerobic 
respiration); and a suitable temperature (to promote enzyme activity).
                            Enzymes
C6H12O6(aq) + 6O2(g) —————————————————————® 6CO2(g) + 6H2O(l)       -DE

However, the effects of other independent variables on either the rate 
or success of seed germination remain to be established; a detailed 
knowledge of these variables is necessary in view of increasing levels
of pollution.

In this investigation, you are required to examine at least four 
variables involved in the germination of seeds; at least two of these 
must be quantitative, and at least one must be qualitative.

Notes
1.  Apart from your notes and standard textbooks, sources of scientific
knowledge include encyclopaedias in libraries, on CD-ROMs, and on the 
Web; it is good practice to include a bibliography in your write-up.

2.  You are provided with several varieties of seeds [including cabbage
(Brassica oleracea), cress (Lepidum spp.), lettuce (Latuca spp.), mung
beans (Phaseolus aureus), mustard (Brassica nigra), rape (Brassica
rapa), pea (Pisum savitum), and sunflower (Helianthus annus)], plant
growth regulators, enzymes, aqueous solutions of salts and acids (each
with an initial concentration of 0.20 mol dm-³), growth substrates, and
light sources.  In addition, you will need to use - within reason -
suitable apparatus. 

3.  The proposed plans of your investigation should be presented in
detail; these plans may be modified as the investigation proceeds.

Dr. R. Peters                                            Contents' List