Quantitative Microscopy

In addition to measuring the size of cells and tissues with the eyepiece or stage micrometers, a number of other quantitative values are utilized for the microscopic evaluation of botanicals (predominantly leaves). These include palisade ratios, vein islet and stomatal numbers, and sto-matal index:

Palisade ratios. The palisade ratio is the average number of palisade cells that occur beneath an epidermal cell. The palisade ratio of many plants remains constant regardless of geographical location of the plant. This can give general subjective information about the characteristics of a plant and can be used to distinguish some closely related species from each other (e.g., Agathosma spp.). The palisade ratio, however, is not applicable to monocot leaves due to a lack of consistent differentiation within the mesophyll (Mukherjee 2002).

Vein islet (veinlet) and vein termination. The term "vein islet" is used to indicate the smallest unit of photo-synthetic tissue encircled by the ultimate divisions of the conducting strands of leaves. The vein islet number is the number of vein islets per square millimeter and is calculated from four contiguous square millimeters in the central part of the lamina, midpoint between the midrib and margin. Various botanicals exhibit consistent values that can allow for the differentiation of closely related species (e.g., Erythroxylum spp.) and can be used when other measures, such as palisade ratio, cannot distinguish between closely allied species. The vein or veinlet termination is the ultimate free termination of a vein or branch of a vein (Trease and Evans 1966).

Stomatal number and stomatal index. The quantification of stomata is a specific assessment tool for leaves. The stomatal number is the average number of stomata per square millimeter of leaf epidermis and the total number of stomata on the leaf. The stomatal index is the percentage proportion of stomata on one surface of the leaf plus the epidermal cells and stomata on the opposite side. Although the stomatal number varies greatly with the age of the leaf, the stomatal index remains highly consistent.

More detailed information on how these measurements are developed is readily available in the primary pharma-cognosy literature.

Table 4.2 Microscopic Characters Used in Computer-Aided Identification of Botanical Ingredients


Was this article helpful?

+1 -1
Chinese Herbs

Chinese Herbs

Worried For Your Health More Than Ever? Want To PREVENT Rather Than CURE Your Illness? Then WE are the only ones who can answer YOUR concern of time by presenting the exclusive work piece, the explicit and special eBook on CHINESE HERBS- the call of time.

Get My Free Ebook


  • kristin
    What is pallaside ratio?
    3 years ago
  • fesahaye
    What is pallisade ratio?
    3 years ago
  • Hamilcar
    What is palisade ratio?
    3 years ago
  • nathan brosnan
    How to calculate vein islet number?
    3 years ago
  • tuulia
    How to obtain palisade ratio?
    3 years ago
  • rebecca
    How to measure Palisade ratio?
    3 years ago
  • Jens
    How to obtain vein islet number?
    3 years ago
  • RITA
    What is stomatal number, palisade ratio, stomatal index?
    3 years ago
  • natascia gallo
    How to calculate stomatal no. stomatal index palisade ratio vein islet no. vein termination no?
    3 years ago
  • Afwerki
    How to count palisade ratio?
    3 years ago
  • josefiina
    How to determined veinlet termination number?
    3 years ago
  • stanley milne
    How to determine vein islet number?
    3 years ago
  • eberardo
    Is palisade ratio constant for a leaf?
    3 years ago
  • sabrina
    How to calculate the palisade ratio on a leaf surface?
    2 years ago
  • Franco
    What is pallishade recio?
    2 years ago
  • iiro
    What is pallishade racio?
    2 years ago
  • christin beyer
    Why we do quantitative microscopy for plant?
    2 years ago
  • banazir
    How to determine palisade ratio?
    2 years ago

Post a comment