what is the nature of the walls of the phloem vessels after they are stained in the microscopic section
To determine the nature of the walls of the phloem vessels after they are stained in a microscopic section, you can follow these steps:
1. Prepare a microscopic section of the phloem tissue: Start by obtaining a small sample of the phloem tissue. This can be done by carefully dissecting or cutting a plant stem or other phloem-containing plant parts. Once you have the sample, fix it in a suitable fixative (e.g., formalin), dehydrate it through a series of alcohol solutions, embed it in paraffin or resin, and finally, cut thin sections using a microtome.
2. Stain the microscopic sections: Choose an appropriate stain that can highlight the cell walls of the phloem vessels. Examples of commonly used stains for this purpose are safranin, toluidine blue, or basic hsin. Follow the manufacturer's instructions for preparing the staining solution and apply it to the sections. Let the stain act for the recommended time.
3. Rinse and dehydrate the sections: After staining, rinse the sections with water or a suitable buffer solution to remove excess stain. Next, dehydrate the sections using a series of alcohol solutions with increasing concentrations, such as 70%, 90%, and 100% ethanol. This step helps remove water from the samples, preparing them for mounting.
4. Mount the sections on microscope slides: Apply a mounting medium, such as a transparent resin or a glycerol-based mounting solution, on microscope slides. Gently place the stained sections onto the mounting medium, ensuring they are positioned evenly and without air bubbles. Cover the sections with a coverslip.
5. Observe the stained phloem vessel walls under a microscope: Use a light microscope at a suitable magnification to observe the stained phloem sections. Focus on the phloem vessels of interest and examine the nature of their walls.
When observing the stained phloem vessel walls, you will be able to see the nature of the cell walls, which are typically stained and appear differently depending on the stain used. The nature of the phloem vessel walls can vary, but commonly, they consist of living cells with primary cell walls made of cellulose and hemicellulose. They might also contain secondary cell wall components like lignin.
Remember, the specific appearance of the phloem vessel walls can be influenced by the stain used, the plant species being examined, and the developmental stage of the tissue. It is crucial to consider these factors while interpreting the results.