B5. Plant Nutrition

 (0654) Coordinated Sciences 2023/2024

Subheadings and Key concepts

• photosynthesis
• investigating the need for
• chlorophyll
• light
• CO2
• investigating the rate of photosynthesis
• light intensity
• temperature
• leaf structure and function
• photosynthesis
• gas exchange
• transport
• importance of magnesium and nitrate ions

6.3. Mineral requirements of plants

 

Nitrate ion and magnesium are essential minerals for plant growth.

Plants need:

• nitrate ions (NO3−) for making amino acids
• magnesium ions (Mg2+) for making chlorophyll

6.2. Leaf structure

 

The leaf is a complex structure that is highly specialized and adapted for photosynthesis!

6.1.3. Glasshouse systems

 

Glasshouses are used in some countries to control conditions for plant growth, especially when the local outside environment isn't ideal for plants. 

Glass traps heat, and inside glasshouses, atmospheric conditions can be controlled.

6.1.2. Investigations for photosynthesis - chlorophyll, light, carbon dioxide

 

Variables tested: chlorophyll, light, carbon dioxide

We use each variable as a limiting factor, which limits the amount of glucose made (product). Some of the glucose is converted into starch. 

We determine the necessity of the variable by conducting a starch test to see how much starch was made.

6.1.1. Photosynthesis: principles and limiting factors

Photosynthesis is:

• the process by which plants manufacture carbohydrates from raw materials 
• using energy from light

04. Plant Nutrition pdf

#48 Summary of plant nutrition

Here is a brief summary of previous topics. 

#47 Plant's mineral requirements and fertilisers

Plants need minerals for healthy growth.

Plant is in need for mineral ions to control chemical activities, grow, and produce materials. The most important minerals are Magnesium ions and Nitrates.

#46 Leaf structure

The leaf consist of a broad, flat part called the lamina, which is joined to the rest of the plant by a leaf stalk or petiole. Running through the petiole are vascular bundles, which then form the veins in the leaf. 

#45 Optimum conditions for photosynthesis in Green house

When plants are growing outside, we can not do much about changing the conditions that they need for photosynthesis. But if crops are grown in glasshouses, then it is possible to control conditions so that they are photosynthesising as fast as possible. 

#44 Limiting factors in photosynthesis

Limiting factor is something present in the environment in such short supply that it restricts life processes.  Three factors can limit the speed of photosynthesis - light intensity, carbon dioxide concentration and temperature.

# 43 Effect of Carbon Dioxide on the Rate of Photosynthesis

When the concentration of CO₂ is low the rate of photosynthesis is also low. (the plant has to spend time waiting for more CO₂ to arrive). Increasing the concentration of CO₂ increases the rate of photosynthesis. 

#42 Effect of Temperature on the Rate of Photosynthesis

When the temperature rises the rate of photosynthesis rises also. There is an optimum temperature  at which the rate of photosynthesis is maximum. Beyond this temperature, the reaction quickly comes to a halt.

#41 Effect of Light intensity on the rate of Photosynthesis

Plants need light energy to make the chemical energy needed to create carbohydrates. Increasing the light intensity will boost the speed of photosynthesis. However, at high light intensities the rate becomes constant.

#40 Photosynthesis investigations – chlorophyll, CO2, light tests

 Investigations to see if chlorophyll, light and CO2 are needed for photosynthesis. 

#39 Photosynthesis investigations - Principles and Starch test

Experiments can be used to find out what factors (CO₂, light, cholorophyll) are needed for photosynthesis. But first of all you need to destarch the plants. To be certain that they are thoroughly destarched, test a leaf for starch before you begin your investigation. 

#38 The equation for photosynthesis

Photosynthesis is the fundamental process by which plants manufacture food molecules (carbohydrates) from raw materials CO₂ and H₂O) using energy from light.