The earliest forms of life known to us date back toabout 3.5 billion years ago. These organisms are called bacteria and blue-greenalgae. Photosynthesis probably first developed in bacteria. The earliest landplants developed a little more than 400,000,000 years ago. The first seed plantsappeared about 350,000,000 years ago and were referred to as seed ferns becauseof their large fernlike leaves.
Plants have different types of growth responses tothe things around them. These responses are called tropisms. There are fourmain types of tropisms. Phototropism is the response to light direction,geotropism is the response to gravity, thigmotropism is the response to water,and chemotropism is the response to a particular chemical.
One of the generalcharacteristics of plants is that they tend to grow continuously throughouttheir lives. There are two aspects of plant growth: primary and secondary.Primary growth takes place in young organs, which results in the increase inlength of shoots and roots. Secondary growth results in the increase in width.Radiation refers to the transmission of energy inwave form and to the transmission of streams of atomic particles through space.Any energy that is emitted through the form of waves is called electromagneticradiation. All kinds of electromagnetic radiation follow the same physicallaws, all travel as fast as light, and when they fall on a surface they emit apressure.
(Global Industries, 1991)There are three types of radiation: alpha, beta, andgamma. Alpha particles are helium-4 nuclei (two protons andtwo neutrons). They interact with matter strongly because of their charges andcombined mass. Their usual velocities can only go through a few millimeters oflow density material. Therefore, this means that alpha particles do not penetratethe outer layers of dead skin cells and do not damage live tissues.
There aresome very high energy alpha particles that are made up about 10% of cosmic raysand they can penetrate the body and even thin metal plates.Beta radiation can penetrate more than alpharadiation can. Beta radiation fromradioactive decay can be stopped by a few centimeters of plastic or a fewmillimeters of metal.
Sometimes beta radiation is used in radiotherapy to givetreatment to superficial tumors. Gamma radiation occurs to get rid of an unstablenucleus of excess energy. Both alpha and beta particles have an electric chargeand mass, and can probably interact with other atoms along their path. However,gamma radiation is composed of photons, which have neither mass nor electriccharge, which makes it be able to penetrate much further through matter thaneither alpha or beta radiation. Gamma rays can be stopped by a thick or denselayer of material, and it doesn’t matter whether the material has high or lowdensity. (Nowicki)Radiation can have a positive effect on plant growthat low levels and harmful effects at high levels.
Radiation can affect aplant’s growth and sprouting. The amount of damage is proportional to theradiation that is received by the plant. Becauseof radiation, soil can become compact and can also lose the nutrients that areneeded for a plant’s growth. Intense radiation kills plants but in a differentway. Trees and shrubs change in their reactivity and sensitivity towardsradioactive substances.
(Taylor, 2017)B. Related StudiesIn the experiment, the proponent will use onespecies of plant to find out how the Wi-Fi radiation will affect it. She willplant two plants of the same species in separate pots. She will place one ofthe pots beside the Wi-Fi router and the other one far away from it. Then shewill compare how fast each plant grows.