This is interesting because it shows you that if you want to manipulate hormones in an experiment you can use plant growth regulators to mimic the action of hormones.
Plant hormones and growth regulators are chemicals that affect flowering; aging; root growth; killing of leaves; prevention or promotion of stem elongation; color enhancement of fruit; prevention of leafing and/or leaf fall; etc.
There are many people who believe that the use of caffeine can
help plants to grow at a higher rate of speed.
On one side of the argument, there are those who feel that adding caffeine to a plant will help it to grow faster. This has been studied time after time, but at this point it is difficult to determine whether the caffeine is at work, or if the beneficial matter is something alongside such as potassium. In other words, caffeine may help in this area but it is hard to say if this is the case if this is not the only substance being used.
Once again, experiments consist of using pop or coffee in order to test the results. The issue with this is that other ingredients may also effect how the plant grows.
Sixteen chemical elements are required for the growth of all plants: carbon, oxygen, and hydrogen (these three are obtained from carbon dioxide and water), plus nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, manganese, zinc, copper, boron, molybdenum, and chlorine. Some plant species also require one or more of the elements cobalt, sodium, vanadium, and silicon.
13 essential mineral nutrien
J. R. Brown (ed.), Recommended Chemical Soil Test Procedures for the North Central Region, Missouri Agricultural Experiment Station, Columbia, 1998
Note the Bibliography. I've highlighted an article, available as a pdf file, with information on interesting experimental procedures for how to handle and test soil. Might be helpful for your experimental design.
Since soil is made up of such diverse materials like broken down rock particles and organic material, it can be classified into various types, though based on the size of the particles it contains.
Sandy Soil- This type has the biggest particles and the size of the particles does determine the degree of aeration and drainage that the soil allows.
formed by the disintegration and weathering of rocks such as limestone, granite, quartz and shale
In a way sandy soil is good for plants since it lets the water go off so that it does not remain near the roots and lead them to decay.
the perfect soil
composed of minerals like Quartz and fine organic particles.
This type of soil can hold more moisture and at times becomes compact.
Clay Soil-Clay is a kind of material that occurs naturally and consists of very fine grained material with very less air spaces
it is difficult to work with since the drainage in this soil is low, most of the time there is a chance of water logging and harm to the roots of the plant
Loamy Soil- This soil consists of sand, silt and clay to some extent
Silty Soil-Silty soil is considered to be one of the most fertile of soils.
out of all the different kinds of soil loamy soil is the ideal for cultivation.
Peaty Soil- This kind of soil is basically formed by the accumulation of dead and decayed organic matter
Though the soil is rich in organic matter, nutrients present are fewer in this soil type than any other type
if the soil is fertilized well and the drainage of the soil is looked after, it can be the ideal for growing plants.
Chalky Soil-Unlike Peaty soil, Chalky soil is very alkaline in nature and consists of a large number of stones.
Typically, stems show positive phototropism (movement toward the light), whereas roots exhibit negative phototropic movement (away from the source of light).
Arabidopsis contains two phototropins referred to as phot1 and phot2. Mutants of Arabidopsis lacking both phototropins lose their phototropic responsiveness
these responses serve to enhance the photosynthetic
Phototropins, like photoreceptor pigments associated with mammalian vision, comprise many amino acids (900–1000) that form the main structure of the protein (the apoprotein) to which an accessory chemical cofactor is bound that can absorb light and impart color (the chromophore)
a small fraction of the receptor pool is rapidly internalized (within minutes) upon blue light irradiation
Phototropins are typically associated with the plasma membrane
However, the biological significance
As light passes through the stem, it becomes progressively diffracted, thereby generating a gradient of phototropin activation across the organ, with the highest level of activity occurring on the irradiated side
In some plant species, including the fern Adiantum capillus-veneris, phototropism and chloroplast movement are induced by red light as well as blue.
novel
The presence of such a hybrid photoreceptor is proposed to enhance light sensitivity and aid the prevalence of species such as ferns in low light conditions