The human body has a complex network of blood cells to circulate food, minerals, waste products and gasses from one part to another. But how does this process takes place in a plant’s body? Do they also have blood vessels? The answer to these questions can be found in biology class 11 syllabus. The chapter Transport in Plants discusses how food and minerals are transferred to all the cells and parts of the plant. Read the following notes to understand the concept better!
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What is Transport in Plants?
Transport in plants refers to the process of carrying water, minerals, and nutrients across various parts of the plant body. This transport includes carrying of food from leaves to other parts and the minerals and water absorbed by the other parts to the leaves, that are referred to as the kitchen of the plants.
Xylem and Phloem are the carriers that transport the necessary minerals, nutrients, etc. in the plants. Xylem is responsible for the transport of water as well as the necessary mineral salts, from the roots to various other parts of the plant, and Phloem transports the sucrose and amino acids that have been developed in the leaves to the other parts of the plant.
In other words, this unit of NCERT biology class 11 aims to help us understand how the three main parts of the plant namely: roots, stem, and leaves, connect for the supply of different things that each part is responsible for.
Also Read: Class 11 Digestion and Absorption
Transport of Water in Plants
Plants need active transport of two main components namely, water from the roots and the food prepared from the leaves to the other parts. Water is transported through Xylem in plants. Xylem is a vascular tissue. It contains more than one type of cells to facilitate the process of transport within the plant system. Xylem carries the dissolved minerals and water to the leaves where, with the help of the chlorophyll, sunlight, and carbon dioxide absorbed from the atmosphere, the leaves can render their function of preparing sucrose which gives energy to the plant for survival.
Transport in plants of water starts from the roots to the stem by way of a potential gradient. The roots of the plant absorb water through apoplast or symplast, and the same is then carried to the stem for absorption by the leaves. The plants need to transport water to the leaves as water is an integral component of the process of photosynthesis. If the plants do not receive water, the process of photosynthesis cannot be completed.
Transportation of Food in Plants
In the previous part of our transport in plant notes, we observed how water is important and how it is transported. Now we will focus on another important part that needs to be equally balanced and that is transport of food from leaves to other parts of the plant.
Food is transported in plants by Phloem, which is again a vascular tissue like the Xylem. The process of transporting food or photosynthates is called translocation in Biology. Phloem contains living cells. Phloem cells are active because they need ATP for the movement of food actively. The living tendency of the Phloem cell is what is responsible for the upward movement of water by Xylem, as it creates the potential gradient that is needed for the upward movement of water.
Also Read: Class 11 Photosynthesis in Higher Plants
Physiology of the Xylem and Phloem
For a better understanding of the chapter transport in plants, we must examine the physiology of Xylem and Phloem. The Phloem comprises two important parts called the sieve tube cells and the companion cells which help the phloem to transport food and minerals to other parts of the plant. Sieve tube members create a running chain of cells that cover the length of the plant. The companion cells run just adjacent to these sieve tube cells and they comprise the organelles and the nucleus and ribosome of these cells supplant the energy needed by the sieve tube cells to diffuse the food from one cell to another.
In Xylem the cells have to fight the very serious force of gravity to supply water upwards and the tracheids and vessel elements. Tracheids are long and thin cells and are connected from end to end. The vessel elements are wider as well as shorter as well as wonder and the end of the Tracheids contain the perforated plates and these plates allow the free flow of water. Therefore, as soon as the potential gradient is generated the water can flow freely from one cell to another and reach its final destination, which is the leaves.
Different Means of Transport in Plants
There are four major means of transport in plants and they are:
|Transport in Plant||Meaning|
|Simple Diffusion||In the process of simple diffusion, substances move from one part to another with the help of a membrane, and in this process, no help from other substances is needed.|
|Facilitated Diffusion||Facilitated diffusion is the process that is the exact opposite of simple diffusion. In facilitated diffusion, the substances move from one membrane to another with the help of other substances such as the transmembrane integral proteins. These proteins are also called the carrier proteins, as they help the transport.|
|Osmosis||Osmosis refers to the tendency of the fluids, in the case of plants majorly water, to be able to pass across a semipermeable membrane to a new solution where the concentration of the solution is higher than the solution of water. This equalizes the concentration of the composition of both the membranes. Osmosis is how roots absorb water in plants.|
|Active Diffusion||Active diffusion is the opposite of osmosis. In the process of active diffusion, the solution with the higher concentration moves towards the solution with the lower concentration. This process happens with the help of cell energy and is often referred to as active transport.|
Importance of Transport in Plants
This chapter on transport in plants is extremely important because it helps in understanding the flow of necessary elements such as minerals, proteins, sucrose, water, nutrients, etc., between various parts of the plant. Without the transport, the plant will not survive, as the different units will not be able to perform their functions that are needed for the proper functioning of the plants.
The survival of the plant depends on the active transport in the plants. You must have observed that many times when there is wear and tear in the body of the plant, the plant dies. This is because the process of transport is interrupted because of wear and tear. Any change in the physiology of the plant affects its transport mechanism.
Also Read: Class 11 Anatomy of Flowering Plants
Why is Transport in Plants Very Slow?
Most of the plant cells are dead and do not have any kind of energy in them. Therefore, their energy needs are also relatively slow. This is the reason why transport in plants is slow, as they do not need high pace transportation as is needed in the body systems of animals because they have more active and living cells than the plants.
We hope that through these pointers on transport in plants, you are now familiar with this important topic. Our experts at Leverage Edu are here to help you get started on the right career path without any hassle. To know more you can book a free career guidance sessions with our experts.