Plant Nutrition
Learning Objective… To describe how plants obtain their nutrition Explain the process of photosynthesis and the role of stomata Analyse the role of green plants in the food and energy chain
Recap….. Define - Heterotrophs Autotrophs Which category do plants fall under? Photosynthesis Transpiration
Mineral Nutrition The roots absorb Minerals from the soil, which contain elements which are essential for plant growth. These are of two types - Macro nutrients – Elements required in large quantities eg C, H, O, N,P, S,K, Ca, Mg.
Micro nutrients – Elements are required in very small amounts (trace elements) They include Fe, Cu, Mn, Mb (Molybdenum), Zn and B(Boron). Of these Fe is the most important.
Among these nutrients, Carbon is absorbed from the air as carbon dioxide Hydrogen and oxygen are absorbed from water and soil.
Mineral transport Minerals must be dissolved in water and are absorbed by the root hairs of the plant. Once absorbed, the mineral solution is transported through the stems to leaves and other parts of the plant through the vascular bundles.
Disease caused by mineral deficiency Lack of any essential nutrient causes deficiency diseases in plants. Please study table on pg 51
Photosynthesis Leaves are the main organs of photosynthesis because their flat shape is ideal for trapping sunlight. They are arranged in a leaf mosaic to expose them equally to the sun. Their cells have chloroplasts to trap the energy from the sun. The network of veins bring in water.
Stomata Guard cells are two bean shaped structures which control the openings called stomata. These stomata are responsible for the exchange of gases and transpiration
Photosynthesis Photosynthesis requires sunlight, water, carbon dioxide and chlorophyll. Chlorophyll captures energy from sunlight and uses it to combine CO2 with H2o to form glucose, a carbohydrate. These carbohydrate molecules join to form starch, proteins and fats. IMPORTANCE: This is the only process which gives: Renewable source of food restores oxygen to the atmosphere