1.1 Defining the problem
1.1.1 Focus/Research Question
Does salinity affect the time it takes for wheat to germinate and then the rate at which it grows from that point onwards?
Germinating wheat seed in a solution of 0% salt content, 2% salt content, and 5% salt content will have the shortest, longer and then the longest germination times, respectively and then growing the shoots in a solution of 0% salt content, 2% salt content, and 5% salt content will have the most growth, less growth and the least growth respectively on a day-by-day basis from the seed’s germination as measured by height for the five days after germination within a reasonable range defined as within the first 7 days.
1.1.3 Background Information/Theory
Salinity in water used to irrigate plants and soil salinity can have a considerable effect on the intensive agriculture of wheat plant germination and growth (Effect of salts on germination of
seeds and growth of young plants of Hordeum vulgare, Triticum aestivum, Cicer arietinum and Brassica juncea. Mer, R.K., P.K. Prajith, D.H. Pandya and A.N. Pandey, 2000). These marked adverse affects take place on a cellular level by affecting cellular diffusion thus affecting the mechanisms of osmosis and interfering with the ionic status of the permeable membranes that surround each of our cells (CiNii.co.jp, Latest Edition, effect of salt concentrations of various plants, website: http://ci.nii.ac.jp/naid/110000978592/). Ion concentration is central to the process of osmosis and excess of certain ions such as NaCl can affect nutrient transfer through the cell (Biology for the IB Diploma, C.J. Clegg, 2007). Indeed, the most possible cause of varietal difference most likely evolves ion transport properties and cellular compartementation (Causes of Varietal differences in
Salt tolerance. In: International congress of plant physiology, Munns, R., 1988). This, of course, affects plant life at all stages, however different plants have varying salt tolerances due to individual differences in biological mechanisms (Handbook of Plant and Crop Stress. Marcel Dekker). Thus, plant salinity is of crucial importance to germination and growth.
Germination and growth is central to farming of many plants. Wheat is a crop of immeasurable importance; in fact 607 metric tons were consumed in 2007. Wheat is the most widely grown food crop in the world, and is increasing in production. It ranks first in world crop production and is the national food staple of 43 countries. At least one-third of the world's population depends on wheat as its main staple. The principal food use of wheat is as bread, either leavened or unleavened (Access Online Encyclopaedia, accessed Monday 23rd of February). Salinity is of particular reference when dealing with harsh arid and semi-desertal climate of Australia (Australian Bureau of Meteorology website, accessed Monday 23rd of February) where salt crystallisation can lead to high salt concentrations in soil as air-born water born salt does not have time to be flushed through to aquifers or removed into the body of plants. Another relevant effect is that reduced rainfall in these said areas means that surface alluvial topsoil experiences salt build-up without being eroded away as would otherwise happen due to rainfall. It is therefore clear that salinity is an issue of some great importance and in this particular experiment, an experiment of singular pertinence with one of the most important global crops at stake, the effect of salt on wheat germination and growth will be tested (World Journal of Agricultural Sciences 4 Effects of NaCl Salinity on Wheat (Triticum aestivum L.) Cultivars).
1.1.4 Investigation Variables
1.2 Controlling Variables
1.2.1. Treatment of Controlled variables