Discover how to determine the Vein Islet Number definition, an average count of vein-islets per square millimeter on leaves.
Vein Islet Number
The vein islet is the small area of green tissue of leaf surrounded by the veinlets (lateral veins). Like an Island, the piece of land surrounded by water.
Vein Islet Number Definition:
The vein islet number define as the average number of vein-islets per square millimeter of a leaf surface midway between the midrib and margin.
How to determine?
It is determined by counting the number of vein-islets in the area of 1 sq. mm. of the central part of the fully matured leaf between the midrib and the margin. At least four determinations should carry out.
Materials and Reagents
- Fully grown leaves from the plant under study.
- Chloral hydrate solution (15 gm of Chloral hydrate in 20 ml of water).
- Microscope with a stage micrometer.
- Camera lucida and drawing board.
- Black paper.
- Pen, pencil, or fine-point marker for drawing.
- Ruler or measuring tools.
Procedure:
- Take the fully grown leaf of the plant under study
- Make suitable size pieces from the central parts between midrib and the margin.
- Dechlorophyllized the pieces of the leaf by boiling in choral hydrate solution for about thirty minutes.
- Arrange camera lucida and drawing board for making drawings to scale.
- Place a stage micrometer on the microscope.
- By using 10x objective and 5x eyepiece, draw a line equivalent to 1 mm as seen through the microscope and draw a square on this line.
- Adjust the black paper on board so that you can see the square in the eyepiece, in the center of the field.
- Place the slide with the cleared leaf (epidermis on the stage).
- Trace all the veins which seen as superimposed on the 1 sq. mm square.
- Draw the vein islets which are more than 60% present within the square.
- Count the number of vein islets in the square millimeter.
- Find the average number of vein islets from the four determinations, to get the average values for one sq. mm.
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Short Answer Question
1. What is a vein islet?
- A vein islet is a small area of green tissue on a leaf surrounded by veinlets. It is similar to an island in that it resembles a piece of land surrounded by water.
2. Define the Vein Islet Number.
- The Vein Islet Number is defined as the average number of vein-islets per square millimeter of a leaf surface, specifically in the central part of a fully matured leaf between the midrib and margin.
3. How to determine Vein Islet Number?
- By counting the number of vein-islets in a 1 square millimeter area of the leaf central region between the midrib and margin.
4. What type of reagent is using for the Vein Islet Number determination?
- Reagents is chloral hydrate solution (15 gm of Chloral hydrate in 20 ml of water), a microscope with a stage micrometer, a camera lucida, a drawing board, black paper and measuring tools.
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