Botanical Preparations PDF 2020/2021

# Genetics (B252) 2020/2021 ## Types of Botanical Preparations - **Non-section preparation** - **Macroscopic preparation** - **Dry preparation** - Bulk specimens - Herbarium sheets - **Wet preparation** - Museum jar - **Microscopic prepa...

# Genetics (B252) 2020/2021 ## Types of Botanical Preparations - **Non-section preparation** - **Macroscopic preparation** - **Dry preparation** - Bulk specimens - Herbarium sheets - **Wet preparation** - Museum jar - **Microscopic preparation** - **Whole mount preparation** - Filamentous form (e.g., Spirogyra) - Thalloid forms - **Smear preparation** - Fluid or semifluid e.g. yeast, diatoms, pollen grains, bacteria - **Squash preparation** - Soft tissues e.g. Feulgen squash technique. - **Macerated preparation** - Tight tissues chemical treatment e.g. hydrolysis of root tips by HCI - **Teased preparation** - Fibrous tissues, e.g. 2ry thickening in xylem vessels - **Peeling of epidermal cells** - Manually, e.g. bean - Sharp blade, e.g. zea - **Section preparation** - **Sectioning** - **Sectioning of unembedded tissues** - **Free hand sectioning** - Rigid tissues - e.g. T.S. in a young stem - **Sectioning with sliding microtomes** - Stiff tissues (difficult to cut by free hand) - **Sectioning with freezing microtomes** - Too soft or fragile tissues - Enveloped in fluid or semifluid medium (external supporting material) - **Advantages:** - Quick - Preserve chemistry of tissues to demonstrate enzyme activity - **Disadvantages:** - Non-serial sections - Thick sections - Sections difficult to cut and stain - **Sectioning of embedded tissues** - **Paraffin technique** - Rotary type - **Celloidin technique** - Sliding type - **Electron microscopy technique** - Ultra type - **Cell and tissue culture** ## Herbarium Sheet - Dry preparation - Macroscopic preparation - Non-section preparation ## Plant Press A plant press is shown in the image. It has straps, which are used to tighten the outer boards. ## Bulk Specimens - Dry preparation - Macroscopic preparation - Non-section preparation ## Museum Jar - Wet preparation - Macroscopic preparation - Non-section preparation ## Types of Microtomes - **Sliding types** - Specimen is fixed. - Razor is moving horizontally. - **Rotary types** - Specimen is moving vertically - Razor is fixed - **Special types (for specific studies)** - **Ultra microtome** - Rotary type (for E.M. sections) - **Freezing microtome** - Freezing agent (solid CO2 or dry ice) - Sliding type - Electrically - Rotary type (cryostat) ## Rotary microtome - Image of a white rotary microtome. It has a large dial with a number 18. ## Sectioning of Unembedded Tissues - **According to nature of tissue** ## Sectioning with Freezing Microtomes - **Advantage:** - Quick - Preserve chemistry of tissues to demonstrate enzyme activity - **Disadvantage:** - Non-serial sections - Thick sections - Sections difficult to cut and stain ## Sectioning of Embedded Tissues - **Paraffin technique** - Rotary type - **Celloidin technique** - Sliding type - **Electron microscopy technique** - Ultra type ## Images - A high-powered microscope is used to view a very small square object. - A microscopic examination of a filamentous form (e.g. Spirogyra) - A microscopic examination of a thalloid form. - A microscopic examination of yeast. - A microscopic examination of stone cells in guava. - A microscopic examination of 2ry thickening in xylem vessels. - A microscopic examination of epidermal cells of a bean - A microscopic examination of epidermal cells of Zea.