Water and organic ions

Water

To transport materials

To maintain structural rigidity- water exerts pressure on cell vacuoles

Photosynthesis

To regulate temperature- water evaporating from leaves helps cool plants down

Magnesium ions

Needed for the production of chlorophyll- needed for photosynthesis

Plant lacking in magnesium ions is yellow due to lack of chlorophyll and stunted in growth due to lack of photosynthesis

Nitrate ions

Needed for the production of DNA and proteins, production of chlorophyll, for plant growth and for seed production

Plants lacking in nitrates will have yellow leaves and stunted growth. Due to lack of chlorophyll and lack of proteins (plants use nitrate ions to build amino acids and polypeptide chains to make proteins)

Calcium ions

Important components in plant cell walls and required for plant cell growth

Plant lacking in calcium ions will be floppy due to calcium's role in plant cell walls (therfore lacks structural support and is floppy). Growth will be stunted due to reduced metabolic activity due to decreased permeability of membranes

REQUIRED PRACTICAL: investigating plant mineral deficiencies

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  1. Make up five nutrient broths: one all minerals, one all except calcium ions, one all except magnesium ions, one all except nitrate ions and one with no minerals (distilled water)
  1. Half fill a test tube with the solution containing all nutrients.
  1. Cover the top of the tube with aluminium foil and push down on covering so that there is a well in the centre.
  1. Gently push the roots of Mexican Hat plantlet through the hole so it is in the solution below.
  1. Repeat steps 1 to 3 with the other 4 solutions.
  1. Wrap all tubes in aluminium foil and place them in the test tube rack on a sunny window sill.
  1. Leave plantlets for approximately one week.
  1. Observe characteristics and growth of the plantlets, comparing each solutions' effects.