Growth of the Plants – Matter and Flow of Energy

Introduction

Plant Growth  

Growth is defined as an organism’s permanent, irreversible rise in size. This characteristic is seen in all species and is accompanied by a number of metabolic processes. Seeds germinate and develop into new seedlings in plants, which eventually mature into adult plants. Plants continue to grow indefinitely. 

Plants take a wide variety of inorganic nutrients from their surroundings, most of which are simple chemicals. Most plants, for example, get their carbon from the environment as gaseous carbon dioxide (CO₂), their nitrogen as the ions (charged molecules) nitrate (NO3–) or ammonium (NH4+), their phosphorus as phosphate (PO43–), and their calcium and magnesium as simple ions (Ca2+ and Mg2+). The ions are dissolved in soil water, which is absorbed by plant roots. These numerous nutrients are used by plants in photosynthesis and other metabolic activities to produce all of the biochemicals required for growth and reproduction. 

Nitrogen – Supports The Growth Of Plant  

The delicate balance of elements necessary for life is a significant topic of study, and nitrogen balance in the environment is no exception. Plants that lack nitrogen become yellow, grow stunted, and produce smaller fruits and flowers. Farmers may apply nitrogen fertilizers to their crops to boost crop growth. Scientists estimate that without nitrogen fertilizers, we would lose up to one-third of the crops we rely on for food and other sorts of agriculture.  

Nitrogen is an essential component of nucleic acid DNA. Deoxyribonucleic acid (DNA) is a self-replicating substance found in practically all living species as the major component of chromosomes and the bearer of genetic information. RNA-Ribonucleic acid is a nucleic acid found in all living cells that functions as a messenger transmitting DNA instructions, which are the most vital biological molecules and essential for all living organisms. DNA contains genetic information, which implies the instructions for building a biological form. Plants cannot create amino acids if they do not receive adequate nitrogen (substances that contain nitrogen and hydrogen make up many living cells, muscles, and tissue). Plants cannot produce the specific proteins required by plant cells if amino acids are not present. Plant growth suffers when there is insufficient nitrogen. Excess nitrogen causes plants to develop too much biomass or organic matter, such as stalks and leaves, but not enough root structure. Plants with extremely high amounts of nitrogen absorbed from soil can harm farm animals who consume them in severe situations.  

Nitrogen Fixation  

Nitrogen enters the soil from the atmosphere. The Earth’s atmosphere includes a massive reservoir of nitrogen gas (N2). However, because the gaseous form cannot be utilized directly by plants without transformation, this nitrogen is “unavailable” to them. N2 must be converted before it can be utilized by plants through a process known as nitrogen fixation. Fixation is the process by which nitrogen in the atmosphere is converted into forms that plants may absorb through their root systems.  

When lightning strikes, it supplies the energy required for N2 to react with oxygen, generating nitrogen oxide, NO, and nitrogen dioxide, NO2. These nitrogen forms then infiltrate soil via rain or snow. Nitrogen can also be fixed in the fertilizer manufacturing process. Under high heat and pressure, air nitrogen and hydrogen combine to make ammonia (NH3), which may then be processed further to produce ammonium nitrate (NH4NO3), a type of nitrogen that can be applied to soils and utilized by plants.  

Mineralization 

Nitrogen is transferred from organic elements like manure or plant materials to an inorganic form of nitrogen that plants may utilize. The plant’s nutrients are eventually depleted, and it dies and decomposes. This is significant during the second stage of the nitrogen cycle. Mineralization happens when bacteria attack organic material, such as animal dung or decomposing plant or animal material; they begin to convert it to a form of nitrogen that plants can utilize. 

Nitrification 

Nitrification occurs in soils as well. During nitrification, ammonia in soils created during mineralization is transformed into nitrites, NO2, and nitrates, NO3. Plants and animals that eat plants may utilize nitrates. Some soil bacteria may convert ammonia to nitrites. Nitrification is crucial to plants because it provides an excess of accessible nitrogen that may be taken by the plants via their root systems. 

Immobilization 

Immobilization is frequently referred to as the opposite of mineralization. Together, these two mechanisms regulate the quantity of nitrogen in soils. When the remains of decaying plants do not have enough nitrogen, soil microbes extract nitrogen from the soil. When bacteria consume ammonium (NH4+) and nitrate (NO3), these nitrogen forms are no longer accessible to plants, resulting in a nitrogen deficit or a shortage of nitrogen. As a result, immobilization binds nitrogen in bacteria. Immobilization, on the other hand, is crucial because it helps manage and balance the quantity of nitrogen in soils by tying it up in microbes.  

Phosphorus – Supports The Growth Of Plant  

Plants readily absorb phosphorus in the form of orthophosphate ions. Phosphorus is important in plants for cell division and the development of new tissue. Phosphorus is also a part of an energy-rich molecule – Adenosine Tri-phosphate. It is an important component of nucleic acid. It helps in root growth and hastens the maturity period of plants. 

Potassium– Supports The Growth Of Plant  

Plants readily absorb potassium in the form of potassium ions (K+). Potassium is very helpful in the translocation of food from leaves to other storage organs of the plant. It also helps in regulating the opening and closing of stomata. Potassium is also important for plants as it is an activator for many enzymes responsible for various metabolism of plants. 

Factors Affecting Plant Growth  

The following are major elements influencing plant growth: 

1. Temperature: As the temperature rises, so does growth. 
2. Light: The intensity, duration, and quality of light all have an impact on various physiological processes in plants. 
3. Water: Water is necessary for plant development. They thrive in adequate amounts of water. They even respond to water scarcity. 
4. Soil Nutrients: Plants require a sufficient amount of nutrients to flourish properly. Plant development is influenced by the quality and amount of nutrients. 
5. Plant Growth Regulators: Auxin, cytokine, gibberellins, and other plant growth regulators are provided to plants to control their growth.