Life Science Short Notes on STOMATAL MOVEMENT - Download PDF!

By Renuka Miglani|Updated : March 16th, 2023

Are you looking for some short and reliable notes during your CSIR-NET preparations? Then, you have come to a perfect place!

Candidates preparing for their CSIR NET exam might need to get some short study notes and strategies to apply while preparing for the key exam of their life. At this point, We at Byjus Exam Prep come up with short notes on STOMATAL MOVEMENT, which comes under the System Physiology Plants section of the Life Science syllabus.

Our experienced subject-matter experts have meticulously designed this set of short notes on the Stomatal Movement to give you the most standard set of study materials to be focused upon. In this cut-throat competitive world, students need to prepare themselves with the best study materials to help them learn and for their future. So, here we are offering the best study notes that are reliable and can be used by the students during their preparations for the upcoming CSIR-NET 2023 exam.

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Study Notes on Stomatal Movement

STOMATAL OPENING

Day time: Light Present +Co2+Chloroplast +water= result in Photosynthesis (Glucose Production). Glucose converted into sucrose and Starch as per the requirement, Transfer in form of Sucrose and Stores in form of Starch.
In the Guard Cells, Starch is converted into malic acid in presence of light (day Time). So, Decrease in Starch contents of guard cells due to conversion. As malic acid is a weak acid, so it dissociates into malate ions(proton).
Protons thus formed are used by the guard cells for the uptake of K+ ions (in exchange for protons). This is an active ionic exchange and requires ATP energy and Cytokinin.
In this way, the concentration of K+ ions increase in guard cells. At the same time, the concentration of H= ions decrease in Guard Cells.
The PH in guard cells also increases simultaneously and becomes alkaline, there is also an increased uptake of Cl(anion) by the guard cells to maintain the electrical and ionic balance inside and outside the guard cells.
The malate anions formed in Guard cells are neutralized by the K+ ions. This results in formation of potassium malate.
It is also observed that the co2 concentration of K+ ions malate and fucose increases, so this increases the osmolytes by decreasing water potential in guard cell.
This causes endosmosis of water inside the guard cell, as water moves its higher concentration to its lower concentration.
This results in high tumour pressure inside the guard cell, and stomata opens due to high pressure.

STOMATAL CLOSING

Absence of light. No Photosynthesis decreased concentration of malic acid in guard cells.
Efflux of K+ ions from guard cells. Influx of H+ ions in guard cells.
Presence of ABA (abscisic acid) favours closing of stomata by blocking uptake of K+ by guard cells in dark. It also prevents efflux of H+ ions from guard cells. ABA and CO2, together help in lowering the PH in guard cells and making the medium acidic. ABA Change the diffusion and permeability of guard cell. This helps in closing of Stomata.
Increase CO2 concentration in and around guard cell due to release of CO2 in respiration Combined with the absence of photosynthetic activity in dark.
Loss of turgidity of guard cell as water exit the guard cell due to high potential of water and low potential of solute inside guard cell.
Finally, Stomata Closing.