And you think photosynthesis is enough for plants to make food right? Nope.... there is more to it actually. After carbohydrate (glucose) is synthesized, some of them need to be converted into amino acids and later from amino acids, proteins are synthesized. For this to occur, plants need minerals. The minerals needed by plants are divided into two groups: Macronutrients and Micronutrients.
MACRONUTRIENTS: Needed in large amount. Examples are Nitrogen, Phosphorus, Sulphur, Magnesium, Potassium and Calcium.
MICRONUTRIENTS: Needed in small amount. Examples are Iron, Manganese, Boron, Cobalt, Zinc, Copper and Molybdenum.
THE ROLE OF MACRONUTRIENTS IN PLANT GROWTH
Do you need to know all these? Hold your horses. In the Biology syllabus, you are required to know the functions and deficiency symptoms of Nitrogen and Magnesium only.
NITROGEN
- Plants generally dependent on nitrogen in the form of nitrate ions or ammonium ions.
- Symptom of deficiency: Chlorosis and stunted growth (Why? Nitrogen is a component of chlorophyll and amino acids and hence proteins are needed for growth. Therefore if plants lack Nitrogen, chlorophyll formation will be affected and there will be insufficient proteins for growth, hence stunted growth)
MAGNESIUM
- Magnesium is also a component of chlorophyll.
- Deficiency symptoms: Chlorosis develops upward from the base of the plant. Unlike in Nitrogen deficiency, yellowing is only in-between the veins (the veins remain green). Chlorosis is accompanied by death of the entire leaf or portions of it.
