1. Chromatography:
Chromatography is a widely used technique in plant physiology experiments to separate and identify different pigments present in plants. It involves the separation of pigments based on their solubility and molecular size using a solvent and a stationary phase.

2. Photosynthesis Measurement:
Photosynthesis is a vital process in plants, and its measurement can be done using techniques like the PAM fluorometry, oxygen evolution, or carbon dioxide assimilation methods. These techniques help in determining the rate of photosynthesis under different conditions.

3. Transpiration Studies:
Transpiration is the process of water loss from plants, and various experiments can be conducted to study its rate and factors affecting it. Techniques like the potometer, gravimetric method, and stomatal density analysis can be used to measure transpiration.

4. Enzyme Assays:
Enzymes play a crucial role in plant physiology, and their activity can be measured using enzyme assays. Techniques like spectrophotometry and colorimetry are commonly used to determine enzyme activity by measuring changes in absorbance or color intensity.

5. Plant Hormone Analysis:
Plant hormones regulate various physiological processes, and their quantification can be done using techniques like high-performance liquid chromatography (HPLC), enzyme-linked immunosorbent assay (ELISA), or gas chromatography-mass spectrometry (GC-MS).

6. Ion Uptake Studies:
To understand the uptake and transport of ions in plants, experiments like ion-selective electrode measurements can be conducted. This technique allows the direct measurement of specific ions in plant tissues or solutions.

7. Water Potential Determination:
Water potential is a measure of the ability of water to move within a plant. Techniques like the pressure chamber method or psychrometry can be used to determine the water potential in plant tissues.

8. Plant Growth Analysis:
Plant growth can be studied by conducting experiments like the measurement of biomass, leaf area, or root length. These experiments help in understanding the effects of various factors on plant growth and development.

9. Respiration Rate Measurement:
Respiration is an essential metabolic process in plants, and its rate can be measured using techniques like oxygen consumption or carbon dioxide evolution methods. These experiments provide insights into the energy metabolism of plants.

10. Leaf Anatomy Studies:
Leaf anatomy plays a crucial role in plant physiology, and experiments like leaf sectioning, staining, or microscopy can be conducted to study the internal structure and arrangement of cells in leaves.

These are some of the common plant physiology experiments and techniques that you should be familiar with for the UPSC Botany optional subject exam. Understanding these techniques will help you analyze and interpret experimental data related to plant physiology effectively.