Determination of vein islet number, vein islet termination and palisade ratio
DETERMINATION OF VEIN-ISLET AND VEIN TERMINATION NUMBER
The vein islet is the minute area of photosynthetic tissue encircled by the ultimate division of the conducting strands. The vein termination number is the number of veinlet terminations per mm of the leaf surface. A piece of the leaf was cleared by boiling in chloral hydrate solution and camera lucida and drawings board were arranged and a 1 mm line was drawn with help of stage mm. A square was constructed on this line in the centre of the field. The slide was placed on the stage.
The veins included within the square were traced off, completing the outline of those islets which overlap two adjustment sides of the square. The average number of vein islets from the four adjoining squares, to get the value for one square mm was calculated. The number of veinlet termination present within the square was counted and the average number of veinlet termination numbers from the four adjoining squares to get the value for 1 square mm was found known as vein termination number.
DETERMINATION OF PALISADE RATIO
A piece of the leaf was boiled in chloral hydrate and was placed under the microscope. Camera lucida and drawing board were arranged and the outline of four cells of the epidermis was traced using a 4 mm objective. Then, the palisade layer was focused down and sufficient cells for covering the tracing of the epidermal cells were traced off. The outline of those palisade cells which were intersected by the epidermal walls was completed. The palisade cells under the four epidermal cells (including cells which are more than half and excluding cells which are less than half within the area of epidermal cells) were counted. The determination for five groups of four epidermal cells from different parts of the leaf was repeated. The average number of cells beneath epidermal cells was calculated known as the palisade ratio.
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