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Anaemia is a condition in which the number of red blood cells or their oxygen-carrying capacity is insufficient to meet physiologic needs, which vary by age, sex, altitude, smoking, and pregnancy status.

Iron deficiency is thought to be the most common cause of anaemia globally, although other conditions, such as folate, vitamin B12 and vitamin A deficiencies, chronic inflammation, parasitic infections, and inherited disorders can all cause anaemia.

In its severe form, it is associated with fatigue, weakness, dizziness and drowsiness. Pregnant women and children are particularly vulnerable.

 WHO programmes and activitiesDepartment of Nutrition for Health and DevelopmentAnaemia in WHO regionsEastern Mediterranean RegionRelated linksNutritionWater-related diseasesAnaemia prevention and controlTechnical anaemias: tools for effective prevention and controlThe global prevalence of anaemia in 2011Global Nutrition Targets 2025: Anaemia policy briefWorldwide prevalence of anaemia 1993-2005Focusing on anaemia: towards an integrated approach [pdf 90.2Kb]More publications on anaemiaStatisticsVitamin and Mineral Nutrition Information System (VMNIS)

Experiment to observe temporary mount of a leaf peel to show stomata!

experiment:

objective:

to prepare a temporary mount of a leaf peel to show stomata.

apparatus and materials required:

a potted tradescantia or bryophyllum plant, forceps, needles, watch glasses, glass slides, a dropper, coverslips, a brush, blotting paper, safranin, glycerine and a compound microscope.

stomata are small openings found widely scattered on the epidermis of leaves and young stems. are mostly found on the lower surface of a dicot leaf and on both the surfaces of a monocot leaf. stomata regulate the exchange of gases and water vapour between the atmosphere and leaves.

procedure:

1. remove a healthy leaf from the potted plant.

2. remove a part of the peel from the lower surface of the leaf. you can do by folding the leaf over and gently pulling the peel apart using forceps. keeps the peel in a watch glass containing water.

3. put a few drops of safranin stain in a watch glass.

4. after 2-3 minutes take out the peel and place it on a clean glass slide.

5. put a drop of glycerin over the peel and place a clean coverslip gently over it with the of a needle.

6. remove the excess stain and glycerin with the of blotting paper.

7. observe the slide under the low-power and -power magnifications of the compound microscope.

observations:

1. the epidermal cells are visible. these are irregular in outline and have no intercellular spaces.

2. many small pores (stomata) are seen scattered among the epidermal cells.

3. each pore is guarded by two bean-shaped guard cells, each containing chloroplasts and a nucleus.

4. the inner concave boundary of each guard cell is , whereas its outer boundary is .

5. the stomata may be open or closed. the guard cells regulate the opening and closing of the stomata.

result:

stomata are present in the epidermal cells of the lower surface of the leaf.

precautions:

1. cut the peel to a proper size and avoid folding it.

2. always place the peel at the centre of the slide and hold the slide at the edges.

3. do not overstrain or under strain the peel.

4. always handle the peel with a brush as a needle may damage the cells.

5. take care to prevent the peel from drying by using glycerin.

6. place the coverslip gently, avoiding any air bubbles.

7. remove excess stain and glycerin with a blotting paper.

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