All questions of Nutrition in Plants for Class 6 Exam

Plants that depend on other plants for food are called parasites. They extract nutrients from their host plant, often harming it in the process.

Fungi are saprotrophs, meaning they obtain nutrients by decomposing dead and decaying organic matter, playing a crucial role in nutrient cycling.

The leaves are modified into some other shape or colour of such plants so that insects get attracted and come near it and they are trapped.

The answer is starch as it is the primary food material produced by Photosynthesis.

Fertilisers and manures replenish nutrients in the soil that are depleted by plant growth, ensuring continued soil fertility and plant health.

Iodine solution is used to test for the presence of starch. When applied to a leaf, it turns blue-black if starch is present, indicating that photosynthesis has occurred.

The primary mode of nutrition for plants is autotrophic nutrition, where they synthesize their own food using sunlight, carbon dioxide, and water. This process, known as photosynthesis, occurs mainly in the leaves of plants due to the presence of chlorophyll. An interesting fact is that photosynthesis not only produces food but also releases oxygen, which is essential for the survival of most living organisms on Earth.

Chlorophyll's main role in photosynthesis is to capture the solar energy, which is then used to convert carbon dioxide and water into carbohydrates. This process is crucial for the synthesis of food in plants.

Structure in Leaves for Gas Exchange
Gas exchange in leaves primarily occurs through specialized structures called stomata. Stomata are tiny pores found on the surface of leaves, mainly in the lower epidermis. These pores are surrounded by two specialized cells known as guard cells.

Function of Stomata
1. Regulation of Gas Exchange: Stomata regulate the exchange of gases such as oxygen and carbon dioxide between the plant and the environment. During photosynthesis, carbon dioxide enters the leaf through stomata, while oxygen produced as a byproduct exits through the same pores.
2. Water Regulation: Stomata also play a crucial role in regulating water loss from the plant through a process called transpiration. The opening and closing of stomata by the guard cells help in controlling the loss of water vapor.
3. Temperature Regulation: Stomata can also regulate the temperature of the leaf by adjusting the rate of transpiration. This helps in preventing overheating of the leaf tissue.

Importance of Stomata
1. Photosynthesis: Stomata facilitate the entry of carbon dioxide, which is essential for the process of photosynthesis. This allows plants to produce glucose and oxygen for their metabolic processes.
2. Respiration: Stomata enable the exit of oxygen, a byproduct of photosynthesis, from the leaf. Oxygen is required for respiration in plant cells.
3. Environmental Adaptation: The number and distribution of stomata on leaves can vary depending on environmental conditions such as light intensity, humidity, and temperature. This adaptation helps plants survive in different habitats.
In conclusion, stomata are crucial structures in leaves that enable the exchange of gases necessary for plant growth and survival. Their specialized function allows plants to maintain proper gas balance, regulate water loss, and respond to environmental changes effectively.

Symbiotic Relationship between Fungi and Algae in Lichens
Fungi and algae have a symbiotic relationship in lichens, where they live together in a mutually beneficial partnership. This relationship is essential for the survival and growth of lichens.

Mutualism
The relationship between fungi and algae in lichens is a form of mutualism, where both organisms benefit from each other. The fungi provide a protective structure for the algae to grow within, while the algae provide essential nutrients through photosynthesis. This mutual exchange of resources allows both organisms to thrive in various habitats.

Structure of Lichens
Lichens are made up of a fungal partner (mycobiont) and an algal partner (photobiont) living together in a symbiotic association. The fungal partner provides a protective environment and absorbs water and nutrients from the surrounding environment. The algal partner, on the other hand, produces food through photosynthesis using sunlight.

Benefits of Symbiosis
The symbiotic relationship between fungi and algae in lichens allows them to colonize harsh environments where neither organism could survive alone. Lichens can grow on rocks, trees, and even in extreme climates like deserts and tundras. This partnership enhances the adaptability and resilience of lichens in diverse ecosystems.

Conclusion
In conclusion, the relationship between fungi and algae in lichens is a prime example of symbiosis in nature. This partnership allows both organisms to thrive in challenging environments by working together and benefiting from each other's strengths.

The rate of photosynthesis decreases if the light intensity decreases, as light is a crucial factor for the process.

Chlorophyll is the green pigment in the leaves responsible for capturing sunlight, which is crucial for photosynthesis. Chlorophyll absorbs light most efficiently in the blue and red wavelengths, while reflecting green light, which is why plants appear green. An additional interesting fact is that chlorophyll is structurally similar to hemoglobin in blood, but instead of iron, it has magnesium at its core.

Plants that derive nutrients from dead and decaying matter are called saprotrophs. They secrete digestive enzymes onto the decaying material to break it down and absorb the nutrients. Fungi, such as mushrooms and molds, are common examples of saprotrophs. An interesting fact is that saprotrophs play a crucial role in ecosystems by recycling nutrients back into the soil, supporting plant growth.

Photosynthesis requires carbon dioxide, water, and sunlight to produce carbohydrates and oxygen. Oxygen is a byproduct, not a raw material.

Nitrogen-fixing bacteria are crucial for plants because they convert atmospheric nitrogen into a form that plants can absorb and use. These bacteria, often found in the roots of legumes, provide plants with essential nitrogen that is needed for protein synthesis and overall growth, thus reducing the need for synthetic nitrogen fertilizers.

Leaves are known as the food factory of plants because they contain chlorophyll and are the primary site of photosynthesis where food is synthesized.

Saprotrophs, such as fungi, absorb nutrients from dead and decaying matter, while parasites depend on living hosts for their nutrition.

Main Function of Guard Cells:
Guard cells play a crucial role in the functioning of leaves by regulating the opening and closing of stomata. Stomata are tiny pores present on the surface of leaves that allow for the exchange of gases such as oxygen, carbon dioxide, and water vapor.

Regulating Stomatal Opening and Closing:
1. Opening: When guard cells are turgid (swollen with water), they bow outwards, creating an opening between them known as the stomatal pore. This allows for the influx of carbon dioxide needed for photosynthesis.
2. Closing: Conversely, when guard cells lose water and become flaccid, they close up, restricting the entry of carbon dioxide and reducing water loss through transpiration. This mechanism helps plants conserve water during dry conditions.

Importance of Stomatal Regulation:
1. Photosynthesis: By controlling stomatal opening, guard cells ensure an adequate supply of carbon dioxide for photosynthesis, the process by which plants produce food using sunlight.
2. Water Conservation: Guard cells help prevent excessive water loss by adjusting stomatal opening based on environmental conditions. This is especially important for plants growing in arid regions or during drought periods.
3. Temperature Regulation: Stomatal regulation also plays a role in temperature control. When stomata are open, water vapor is released through transpiration, cooling the leaf surface. Closing stomata reduces water loss and helps maintain optimal leaf temperature.

In conclusion, guard cells are essential for maintaining the balance between gas exchange and water conservation in plants. Their ability to regulate stomatal opening and closing ensures efficient photosynthesis, optimal water usage, and temperature regulation, contributing to the overall health and survival of plants.

Desert plants’ leaves are often modified into spines to reduce water loss through transpiration, helping them survive in arid conditions.

Nitrogen in the soil is converted into a usable, soluble form by bacteria, such as Rhizobium, which helps plants utilize nitrogen for growth.

Adding Fertilizers to Soil
Adding fertilizers to soil serves the primary purpose of providing essential nutrients to plants for their optimal growth and development. This practice is vital for maintaining soil fertility and ensuring healthy plant growth.

Key Points:
- Nutrient Supply: Fertilizers contain essential nutrients like nitrogen, phosphorus, and potassium which are crucial for plant growth. These nutrients may be deficient in the soil naturally or depleted over time due to continuous cultivation. Adding fertilizers helps replenish these nutrients, promoting healthy plant growth.
- Improving Soil Fertility: Fertilizers not only provide nutrients to plants but also contribute to improving overall soil fertility. Nutrient-rich soil supports a diverse range of plant life and enhances the overall health of the ecosystem.
- Enhancing Crop Yield: By supplying plants with the necessary nutrients, fertilizers help increase crop yield and improve the quality of the produce. This is especially important in agricultural practices where high productivity is essential.
- Promoting Plant Health: Adequate nutrient supply from fertilizers ensures that plants are healthy and resistant to diseases and pests. Strong, healthy plants are better equipped to withstand environmental stressors and produce higher yields.
In conclusion, the primary purpose of adding fertilizers to soil is to supply essential nutrients to plants, improve soil fertility, enhance crop yield, and promote overall plant health. This practice is essential for sustainable agriculture and ensuring food security for the growing global population.