Plant Physiology Meaning
The branch of Science that deals with the study of structure and function of plants and its parts is known as Plant Physiology. Plants' importance is equal to any other living organism that is present on our planet earth. Plants basically are the reasons by which most of the organisms are surviving on earth. Plants provide us with oxygen in which we breathe. Besides this there are a number of sources we are going to get from plants. We even get our food from the plants. Plants fulfill all the basic necessities of an organism. This Plant Physiology topic will help you to understand about the functions and other important structures of plants.
We know that plants are the organisms that prepare their own food, that is, they are autocross. Plants prepare their food through chlorophyll with the help of sunlight. There are certain structures in plants that help them to prepare their own food. In this topic you are going to learn about these structures. Plant Physiology will give you a brief detail about all the plant parts along with their functions that they perform. In this way you can easily learn the way in which food is being prepared on its own by plants.
Plants have various parts including stems, leaves, roots and other parts that have different functions which enable them to survive . They release oxygen as a by-product of their respiration. For survival with water and carbon dioxide plants need to develop mechanisms which result in the release of oxygen in the atmosphere. There are various plant processes like mineral and nutrition, transportation, respiration and plant growth and development. In this topic of Plant Physiology you will get the information about the Ecole process along with the parts in the plants.
Plant Parts and Functions
Plants have different body parts like Roots, Stem, Leaves, Flowers, and Fruits. Following are the different parts of plants and their functions: -
Roots
Roots are known as the foundation system for the plants and keep the plants firmly grounded in the soil. The main function of the root is water and minerals absorption from the soil. It helps to synthesize plant growth and regulates reserve food material. Roots help to keep plants fixed on a particular place. The plants cannot move from one place to another, that is, they cannot show locomotion. The main reason is these roots which not only make them still but also provide them with nutrition .
Stem The stem is a part of the plant found above the ground. The color of the tree stem is brown, while the younger stems are green. The important functions performed by the stem are: -
It facilitates the important process of photosynthesis in plants.
It offers a proper structure to a plant, which later helps it develop into a tree.
Another important function of the stem is to carry up leaves, flowers, buds, and fruits to the plant.
It transports water, minerals, and ready food from the leaves to other parts of the plant.
The stem also helps to protect phloem and xylem and also allows them to perform their normal functions.
Minerals and nutrition is the water that the root carries from the soil is transferred to other parts of the body with the help of the stem. Stem has xylem and phloem that helps in conduction of food and water both. The water is conducted from roots to other body parts while the nutrition or food from leaves is conducted to other body parts with the help of stem.
Leaves
Leaves are another essential part of a plant. They contain chlorophyll that helps the plant with the process of photosynthesis using sunlight, carbon dioxide, and water. The food that the whole plant needs is made up in this part , that is in the leaves. The food from this part is carried to other body parts of the plant through the stem. Here you will get a brief information about the process through which food is prepared in our leaves. A leaf has three main parts- leaf base, lamina, and petiole. The main functions of a leaf are: -
1) Transpiration: Apart from photosynthesis, leaves play an essential role within the removal of far more than water from plants through tiny pores called stomata. There is excess water in the plant's body and this excess water is removed out from the plant through leaves by the proceeds of transpiration.
2) Photosynthesis: Green leaves prepare the food with the help of water and carbon dioxide in the presence of sunlight with the process of photosynthesis. Water from the roots come into these leaves through the stem then the leaves gather carbon dioxide from the atmosphere along with this in the presence of sunlight the food is prepared in the leaves. This is the reason that plants are autographs because they prepare their own food.
3) Reproduction: Leaves of some plants also help with the reproduction. For e.g., leaves of Bryophyllum produce a brand new Bryophyllum plant. Anther and filament are the respective male and female kart that will help in the reproduction in plants. These reproductive parts are present mainly on the flowers. In the presence if these parts a plant is characterized as asexual, bisexuality and unisexual plant.
Flowers
Flowers are the foremost beautiful and vibrant part of a plant. They are, in fact, the part of a plant that reproduces. A flower has four major components: petals, sepals, stamens, and carpels. Petals are the colorful part of the flower that makes it look more attractive. Sepals are the greenish color part of the flower. Carpels and stamens are the male and female reproductive part of the plants. These parts together make a flower.
Fruits
Fruits are the most important of a seed plant. The mature ovary in the plant when fertilized with the other segments commonly known as pollen grains produces a seed. This seed further develops into a fruit. Some of the fruits that develop without fertilization are commonly referred to as Parthenocarpy fruits, that means the fruit without fertilization.
Mineral Nutrition in Plants
It is essential for the growth of the plant. It gives insight to methods to identify the essential elements of the plants. These minerals in plants spot their essentiality, deficiency symptoms, and mechanism of absorption elements. It also conveys the importance of the biological process. Macro and micronutrients present in plants do essential processes like cell-membrane permeability, osmotic concentration of cell sap and its maintenance, enzyme activity, and then on.
Nutrition Transportation in Plants
Plants have a definite system (xylem and phloem), which helps in transporting nutrients and water from roots to any or all the parts of the plant through translocation. Transport of water and nutrients in rooted plants is unidirectional or multidirectional. Modes of transportation can either be passive, which occurs through diffusion, facilitated diffusion to be precise, or maybe through effective methods meted out by specific membrane proteins, which are called pumps.
Photosynthesis in Higher Plants
Photosynthesis is essential because it is the primary source of food for all living entities on earth. It releases oxygen within the atmosphere, which all living organisms inhale to breathe. It takes place in chloroplasts through light and dark reactions using four pigments i.e. xanthophyll, chlorophyll, chlorophyll, carotenoids. Extracting energy from oxidizable substances and storing within the kind of bond energy is phosphorylation. In plants, cyclic and non-cyclic photophosphorylation occur.
Respiration in Plants
Food that’s required for keeping processes comes from photosynthesis. Metastasis ends up in the discharge of energy, which is employed for the synthesis of ATP, which involves glycolysis. Aerobic respiration ends up in complete oxidation of organic substances within the presence of oxygen, which is common in higher organisms. Another vital aspect of respiration is the ratio of the degree of CO2 released to the quantity of oxygen consumed.
FAQs on Plant Physiology
1. What is Plant Physiology and what major processes does it cover?
Plant Physiology is a branch of biology that studies the vital life processes and functions of plants. It explores how plants grow, develop, and respond to their environment at a molecular, cellular, and organismal level. Key processes covered include photosynthesis (food production), respiration (energy release), transpiration (water movement), transport of water and nutrients, mineral nutrition, and the role of plant hormones in growth and development.
2. What are the primary physiological functions of a plant's main parts like roots, stems, and leaves?
Each part of a plant has specific physiological roles essential for its survival:
- Roots: Primarily responsible for anchoring the plant and absorbing water and mineral nutrients from the soil. They also store food reserves and synthesise certain plant growth regulators.
- Stems: Provide structural support, positioning leaves to receive sunlight. They contain vascular tissues (xylem and phloem) that transport water, minerals, and food throughout the plant.
- Leaves: The main sites for photosynthesis, where sunlight is converted into chemical energy. They also play a crucial role in gaseous exchange and transpiration through tiny pores called stomata.
3. How do photosynthesis and respiration differ in plants, and why are both essential for survival?
Photosynthesis and respiration are two contrasting yet interdependent processes. Photosynthesis is an anabolic process that uses light energy, water, and carbon dioxide to create glucose (food) and release oxygen. It occurs only in chlorophyll-containing cells and during the day. In contrast, respiration is a catabolic process that breaks down glucose to release energy (ATP) for the plant's metabolic activities, consuming oxygen and releasing carbon dioxide. Respiration occurs in all living cells, day and night. A plant needs photosynthesis to produce food and respiration to get energy from that food to live and grow.
4. What is transpiration and why is it often called a 'necessary evil' for plants?
Transpiration is the physiological process of water movement through a plant and its evaporation from aerial parts, primarily from leaves through stomata. It is called a 'necessary evil' because while it is essential for creating the 'transpirational pull' that draws water and minerals up from the roots, it also leads to a significant loss of water. If a plant loses more water than it can absorb, it can lead to wilting and stress. However, without this process, nutrient transport to the top of the plant would be impossible.
5. How do plant hormones, or growth regulators, control plant development?
Plant hormones are chemical compounds that act as signals to regulate growth, development, and responses to environmental stimuli. They work in very small concentrations and can have different effects depending on the target tissue and their concentration. For example:
- Auxins promote stem elongation and are responsible for phototropism (the bending of a plant towards light).
- Gibberellins stimulate seed germination, stem growth, and flowering.
- Cytokinins promote cell division and delay the ageing of leaves.
- Abscisic acid (ABA) is a stress hormone that promotes dormancy and stomatal closure during water scarcity.
6. Why is the transport of water in the xylem considered a passive process, while sugar transport in the phloem is active?
The transport of water in the xylem is largely passive because it is driven by physical forces, primarily the transpirational pull from the leaves, and does not require the plant to expend metabolic energy (ATP). In contrast, the transport of sugars (translocation) in the phloem is an active process. It requires the plant to use ATP to load sugars from the leaves (the source) into the phloem tubes and unload them at a destination like roots or fruits (the sink). This energy-dependent mechanism allows the plant to move sugars against a concentration gradient.
7. What is the key difference between macronutrients and micronutrients for a plant?
The key difference lies in the quantity required by the plant, not their importance, as both are essential for survival. Macronutrients are elements required in relatively large amounts, such as Nitrogen (N), Phosphorus (P), and Potassium (K). They are major components of organic molecules like proteins and nucleic acids. Micronutrients, or trace elements, are required in very small quantities. Examples include Iron (Fe), Manganese (Mn), and Zinc (Zn), which typically function as co-factors for enzymes in metabolic pathways.
8. Who is known as the father of Plant Physiology?
Stephen Hales, an English clergyman and scientist, is widely regarded as the 'father of Plant Physiology'. His pioneering experiments in the 18th century on plant transpiration, water movement, and gas exchange laid the foundational groundwork for understanding how plants function.
