Class Rules 1.Punctuality a.The last person to come into the class later than me will teach the class for 2 minutes on a selected topic by yours truly. b.Homework to be returned during the first Theory lesson of the week. 2.Cleanliness 3.Courtesy a.If you need to speak, raise your hands. b.If someone is speaking, open your ears, and not your mouth. 4.Consistency a.You must always have your notes with you. 5.Commitment a.If you are tasked to do something, I expect it to be done with all your effort.

Plant Nutrition Photosynthesis

5.1 Plant Structure & Function 5.2Photosynthesis 5.3Leaf Adaptation & Photosynthesis 5.4Plant Mineral Nutrition 5.1.1General Plant Anatomy 5.1.2Leaf Structure and Function 5.1.3Structural Diversity in Flowering Plants 5.2.1The Importance of Photosynthesis 5.2.2Essential Conditions for Photosynthesis 5.2.3Plant pigments 5.2.4Absorption and Action Spectra 5.2.5Photosynthesis – The Process 5.2.6Fate of the Products of Photosynthesis 5.2.7Factors Influencing the Rate of Photosynthesis 5.2.8Compensation Point 5.2.9Role of Guard Cells Water and Carbon Dioxide Uptake 5.4.1Nitrates 5.4.2Magnesium 5.3.1Structural Adaptations 5.3.2Sun & Shade Leaves Plant Nutrition Topic Overview

Learning Objectives By the end of the lesson, you should be able to: i)* Describe mechanism of stomatal opening and factors that influence stomatal opening.

Guard Cells Structure

Key Features of guard cell that are adapted to its function of controlling the stomatal pore size: (1)Asymmetrical thickness of the cellulose cell wall. Thicker on the side that is nearer to the stomatal pore, and thinner on the side that is further away from the pore. (2)Abundance of chloroplasts. Atypical feature of a cell of the dermal tissue system. Abundant chloroplasts Cellulose cell wall thicker on side nearer to the stomatal pore.

Mechanism for Opening 1.In the dark, the stoma remains closed. 2.Once exposed to sunlight, photosynthesis is initiated and energy is harnessed. 3.The guard cells can now actively pump potassium ions from the neighbouring epidermal cells into their cytoplasm. 1.In the dark, the stoma remains closed. 2.Once exposed to sunlight, photosynthesis is initiated and energy is harnessed. 3.The guard cells can now actively pump potassium ions from the neighbouring epidermal cells into their cytoplasm. 4.This lowers the water potential in the guard cell. 5.Resulting in water diffusing into the guard cell through osmosis. 6.The guard cells begin to swell. 4.This lowers the water potential in the guard cell. 5.Resulting in water diffusing into the guard cell through osmosis. 6.The guard cells begin to swell. 9.Consequently, both guard cells bending away from each other, thus opening the stoma. 7.Due to the thicker cell wall on the inner margins of the guard cell (ie. nearer to the stomatal pore), swelling results in a smaller degree of curving along the inner margins. 8.The thinner cell wall on the outer margins of the guard cell (ie. further away from the stomatal pore) allows for a greater degree of curving as the cell swells. 7.Due to the thicker cell wall on the inner margins of the guard cell (ie. nearer to the stomatal pore), swelling results in a smaller degree of curving along the inner margins. 8.The thinner cell wall on the outer margins of the guard cell (ie. further away from the stomatal pore) allows for a greater degree of curving as the cell swells.

Mechanism for Closure 4.This lowers the water potential in the guard cell. 5.Resulting in water diffusing out of the guard cells through osmosis. 6.The guard cells begin to turn flaccid. 4.This lowers the water potential in the guard cell. 5.Resulting in water diffusing out of the guard cells through osmosis. 6.The guard cells begin to turn flaccid. 1.When there cease to be light, photosynthesis also ceases. 2.Potassium ions begin diffusing out of the guard cells. 1.When there cease to be light, photosynthesis also ceases. 2.Potassium ions begin diffusing out of the guard cells. 7.This leads to stoma closure.