Introduction
The term magnesium was derived from the word magnesia which is the district in Greece from which magnesium was first mined. The importance of magnesium in plants was discovered by scientists such as Mayer, Knop, Sachs, and Salm-Horstmar; and then in 1904-1902, Willstarter identified magnesium to be part of chlorophyll. Research has also shown that magnesium is a cofactor in the enzymatic processes associated with phosphorylation and dephosphorylation and in the hydrolysis of various compounds and it has also been shown to act as a structural stabilizer in various nucleotides.
Magnesium deficiency may suppress the increase in plant mass or a decrease in shoot growth, the extent of the shoot or root growth inhibition is dependent on the stage of the plant development, the plant type, environmental conditions, and the general nutrition of the plant. High levels or low levels of magnesium concentration may decrease fruit yield and quality. For example, in observation of cultivations of apples, magnesium fruit concentration had a negative correlation to the fruit color while potassium concentration on the fruit had a positive correlation to the fruit color. The effect of magnesium was shown to have resulted from the antagonistic effects of potassium concentration (Allen, Barker, and Pilbeam2007).
Why Do Plants Require Magnesium for Growth?
Magnesium deficiency affects plant growth by interfering with chlorophyll formation thereby leading to a reduction in the number of nutrients produced by the plant for its use and as a result, an overall rate of growth is affected.
Hypothesis
Plants require magnesium for the synthesis of chlorophyll that is normally needed in the process of photosynthesis to provide nutrients for the plant.
Prediction
If the amount of magnesium supply to a plant is increased to an optimum level, then the rate of plant growth will increase, while a decrease in the magnesium concentration will lead to lowered growth rates (Norman and Ulrich, 1973).
Controlled Experiments and Methods
In the experiment, two cultures were prepared; one without magnesium added to it whiles the other had magnesium added to it. At the same time, the other factors such as light, oxygen, and substrate concentration were kept constant. In the beginning, the amount of oxygen gas being produced will be equal in both cultures but after some time the amount in the culture lacking magnesium will start reducing.
The reduction in the amount of oxygen being produced from the experiment lacking magnesium meant that there was a reduction in the rate of photosynthesis while in the other experiment, the volume of oxygen rose steadily as there was enough chlorophyll to trap the light energy from the sun required for photosynthesis. In the experiment, the volume of oxygen will be collected at an interval of thirty minutes for each of the experiments. The data will be recorded for the two sets of the experiment against each of the time intervals.
The Results
Conclusion /Discussion
The hypothesis that magnesium is essential for photosynthesis is supported. Magnesium is essential for the manufacture of chlorophyll. Chlorophyll traps light energy from the sun and uses it to split the water molecule. The oxygen atom split from the water molecule combines with the carbon dioxide molecule to form glucose. A molecule of oxygen is released in the process according to the following equation:
Carbon dioxide + Water molecule=Glucose + Oxygen
A decrease in the amount of magnesium or a complete lack of it will mean very little chlorophyll is available to trap the light energy needed for splitting the water molecule. The rate of photosynthesis will therefore be reduced as a result of this. Magnesium availability is therefore essential for photosynthesis and lack of its results in reduced rates of photosynthesis which may consequently result in necrosis.
Practical Application
It’s therefore important to ensure an optimum supply of magnesium to the plants as they grow in if good returns are to be realized. This can be through the provision of magnesium-containing fertilizers and manures. In an experiment done to compare the effectiveness of the organic and inorganic fertilizers, it was noted that “there appeared to be no long-term benefit of using organic amendments, as organic fertilizers did not improve residue conditions (organic matter content, pH, electrical conductivity, activity of Na+ ions) compared with the inorganic fertilizer. It was concluded that inorganic fertilizer could provide a suitable, cost-effective alternative to poultry manure” (Eastham, Morald, and Aylmore, 2006).
References
Allen V. et al. (2007). Hand book on plant Nutrition. Illustrated. CRC Press. Web.
Eastham, J. et al. (2006). Water, Air, & Soil Pollution: Effective Nutrient Sources for Plant Growth on Bauxite, Residue, Comparing Organic and Inorganic Fertilizers. Web.
Norman T. and Ulrich A. (1973). Effects of Potassium Deficiency on the Photosynthesis and Respiration of Leaves of Sugar Beet. Web.