Determination of stomatal number

Stomatal number: It is the average number of stomata per square mm of the epidermis of the leaf.

Procedure:

  1. Clear the piece of the leaf (middle part) by boiling with chloral hydrate solution or alternatively with chlorinated soda. Peel out the lower and upper epidermis separately by means of forceps. Keep it on slide and mount in glycerin water.
  2. Arrange a camera lucida and drawing board for making the drawings to scale.
  3. Draw a square of 1mm by means of stage micrometer.
  4. Place the slide with cleared leaf (epidermis) on a stage. Trace the epidermal cell and stomata.
  5. Count the number of stomata present in the area of 1 sq mm. Include the cell if at least half of its area lies within the square.
  6. Record the result for each of the ten fields and calculate the average number of stomata per sq mm.

 

Number of stomata per sq mm

Upper surface

Lower surface

Cassia auriculata

100-200

130-260

Atropa belladona

7.5- 17.5

77.5- 176

Cassia angustifolia

180-223

195-257

 

The stomatal number is affected by various factors like the age of the plant, the size of the leaf, environmental conditions, etc.

An increase in CO2 decreases stomatal density. Thus, the stomatal number gives an idea of environmental change.

      The number of stomata per unit area increases under more xerophytic conditions.



                


https://www.youtube.com/watch?v=rUZJF178i_U


Comments

Post a Comment

Popular posts from this blog

Lassar' s paste

Image
PASTES  Pastes are semisolid dosage forms that contain one or more drug substances intended for topical application. Synonym : Zinc and Salicylic acid paste BP 1988      Theory : Lassar's paste is named after scientist Oskar Lassar, he developed it for treatment of eczema. Zinc oxide works by forming a barrier on top of the skin that protects the area from moisture and irritants. Starch enhances viscosity. This medication is also used treat and prevent diaper rash and other minor skin irritation, burns, cuts, scrapes. THE LASSAR'S PASTE      SR     NO. INGREDIENTS     QTY ROLE 1 Zinc oxide 240g     Astringent 2 Salicylic acid 20g    Keratolytic agent 3 White soft  paraffin 500g      Emollient 4 Starch 240g     Absorbs moisture   Procedure:  1. The white soft paraffin was melted by warming
Read more

White Liniment

Image
LINIMENT   Liniment (from the Latin linere, to anoint), or embrocation, is a medicated topical preparation for application to the skin.  Sometimes called a heat rub, liniments may be water-like in viscosity or formulated as a lotion or balm and are usually rubbed in to allow for penetration of the active ingredients.  Liniments are solution or mixture of various substances in oil,alcoholic solution of soap or emulsion and may contain suitable antimicrobial preservatives.  They are for EXTERNAL USE ONLY .  General uses of liniment   Antipruritic,astringents,emollients,analgesics,rubefecient,counterirritant There are two types of Liniments:  Alcoholic liniments  Oleaginous liniments.  Liniments with an alcoholic or hydroalcoholic   vehicle are useful when rubefacient,   counterirritant, or penetrating action is   desired. Oleaginous liniments are employed   primarily when massage is desired. By their   nature, oleaginous liniments are less irrita
Read more