Chapter 5: Plant nutrition Flashcards
Formula for photosynthesis
6CO2 + 2H2O —–> C6H1206 + 6O2
What is Photosynthesis
The fundamental process by which plants manufacture carbohydrates (sugars) from raw materials using energy from sunlight.
Key requirements for photosynthesis
Carbon dioxide (CO2) is absorbed from the atmosphere through stomata (tiny pores) in leaves.
Water (H2O) is absorbed from the soil through the roots.
Light energy is captured by chlorophyll, a pigment present in chloroplasts within plant cells.
Products after Photosynthesis
Glucose (a simple sugar) and oxygen (O2) are released as a gas.
Importance of Photosynthesis
Provides the primary source of energy for plants (glucose used for cellular respiration).
Supports the production of other organic molecules needed for growth and development.
Oxygen released during photosynthesis is essential for respiration in plants and animals.
Factors Affecting Photosynthesis
Light intensity, Carbon dioxide concentration, Temperature and Water availability
Light intensity
Increased light intensity generally increases the rate of photosynthesis up to a point, beyond which it may damage the photosynthetic apparatus.
Carbon dioxide concentration
Higher CO2 concentration can enhance photosynthesis up to an optimal level.
Temperature
The optimal temperature range for photosynthesis varies depending on the plant species. Extreme temperatures can disrupt the process.
Water availability
Water is essential for various aspects of plant function, including photosynthesis. Drought stress can significantly reduce photosynthetic activity.
Mineral Nutrients for photosynthesis
Plants also require mineral nutrients from the soil for proper growth and development. These are absorbed by the roots in the form of dissolved ions.
Essential elements and Deficiency symptoms
Essential elements for photosynthesis
Some key elements needed by plants include nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), and calcium (Ca).
Deficiency symptoms
Lack of specific mineral nutrients can lead to visible deficiencies in plants, affecting growth, leaf colour, and overall health.
Importance of Plant Nutrition
Understanding plant nutrition is crucial for various fields, including agriculture, horticulture, and environmental science.
Proper management of soil nutrients and environmental factors can optimize plant growth and crop yield.
Describe the significance of the features of a leaf in terms of functions, including:
– palisade mesophyll and distribution of chloroplasts
– photosynthesis
– stomata, spongy mesophyll cells and guard cells
Palisade Mesophyll & Chloroplasts: These densely packed cells in the upper layer contain abundant chloroplasts, maximizing sunlight capture for photosynthesis.
Stomata, Spongy Mesophyll & Guard Cells: Tiny pores (stomata) controlled by guard cells allow CO2 intake for photosynthesis. Spongy mesophyll cells with air spaces facilitate gas diffusion (CO2 in, O2 out).