Plant traits and adaptation are controlled by or influenced by factors related to plant growth. Genetics and environment are the two main determinants of plant growth and development.
Because the gene—the fundamental unit of plant expression—is housed inside the cell, the genetic factor is also referred to as an internal factor. All biotic and abiotic factors other than the genetic factor are referred to as the environmental factor, which is an external factors.
Different interactions exist between the two plant growth factors. A plant’s character is determined by its genetic makeup, but how much of it manifests depends on the environment.
9 Environmental Factors Affecting Plant Growth
Environmental elements that have an impact on plant growth and these elements are:
- Moisture Supply
- Radiant Energy
- Composition of the Atmosphere
- Soil Structure and Composition of Soil Air
- Soil Reaction
- Biotic Factors
- Supply of Nutrient Elements
- Absence of Growth Inhibiting Substances
The limit of survival for living things has typically been reported to be between -35°C and 75°C. Temperature is a measure of heat intensity. Most crops can grow between 15 and 40 degrees Celsius. Growth declines quickly at temperatures that are much below or above these limitations.
Because they vary depending on the species and variations, length of exposure, age of the plant, stage of development, etc., ideal temperatures for plant growth are dynamic. The temperature has an impact on key plant metabolic processes such as photosynthesis, respiration, evapotranspiration, etc.
In addition to these, temperature impacts how well nutrients and water are absorbed, as well as how microbial activity affects plant growth.
2. Moisture Supply
Because growth is constrained at both extremely low and extremely high soil moisture regimes, the growth of different plants is related to the amount of water present. Water is necessary for plants to produce carbohydrates, keep their protoplasm hydrated, and transport nutrients and mineral elements.
Internal moisture stress reduces cell division and cell elongation, which in turn reduces growth. In addition to these, water stress has an impact on a variety of physiological processes in plants.
The way the soil is moist has a significant impact on how well nutrients are taken up by plants. Because each of the three main nutrient uptake processes—diffusion, mass flow, root interception, and contact exchange—is impaired by low moisture regimes in the root zone, fewer nutrients are available to plants.
Generally speaking, nitrogen absorption increases when the soil moisture regime is high. The soil moisture regimes have an indirect impact on the soil microorganisms and different soil pathogens that cause different diseases, which in turn has an indirect impact on plant growth.
3. Radiant Energy
Plant growth and development are significantly influenced by radiant energy. It consists of three elements: light quality, intensity, and duration. All of these radiant energy constituents have a major impact on different physiological processes in plants and, consequently, plant growth.
However, comparable to broad daylight, light intensity is crucial for healthy plant growth. Crop growth can be significantly impacted by variations in light intensity brought on by shade. The absorption of phosphate and potassium is significantly influenced by light intensity. Additionally, it was shown that as light intensity increased, the roots’ intake of oxygen increased.
From the perspective of the majority of field crops, light quality and intensity may be of minor importance, but the length of the light cycle is crucial. Photoperiodism describes a plant’s behavior over the length of the day.
Plants are categorized as the short day (those that flower only when the photoperiod is as short or shorter than some critical period, such as in the case of tobacco), long day (those that bloom only when the amount of time they are exposed to light is as long or longer than some critical period, such as in the case of grains), and indeterminate (those that flower and complete their reproductive cycle over a wide range of time).
4. Atmospheric Composition
Carbon is the most prevalent element in plants and other living things, therefore it is necessary for plant growth. The atmosphere’s CO2 gas is the primary source of carbon for plants. It enters its leaves and becomes chemically bonded with organic molecules as a result of photosynthetic action.
Typically, the atmospheric CO2 concentration is only 300 ppm or 0.03 percent by volume. As a byproduct of the respiration of both plants and animals, carbon dioxide is continuously released back into the atmosphere.
A significant source of CO2 gas is the microbial breakdown of organic wastes. According to reports, as atmospheric CO2 concentrations rise, photosynthesis becomes more temperature-sensitive.
5. Soil Structure and Soil Air Composition
Soil structure has a significant impact on plant growth, particularly root and top growth. The bulk density of soil is also influenced by its structure. In general, the soil becomes more compact, the soil structure is less clearly defined, and there is less pore space, which limits plant development, the greater the bulk density.
High bulk densities provide enhanced mechanical resistance to root penetration and suppress the development of seedlings. Additionally, bulk density has a significant impact on root respiration and the rate of oxygen diffusion into soil pore spaces, both of which have a significant impact on plant growth. At the root absorbing surface, the oxygen supply is crucial.
Therefore, to maintain sufficient partial pressure at the root surface, it is vital to consider both the overall oxygen content of soil air and the pace at which oxygen diffuses through the soil.
Therefore, it can be stated that an appropriate root oxygen supply, which might affect plant growth, is the limiting factor for the maximum yields of the majority of crops (apart from rice).
6. Soil Reaction
soil response affects plant nutrition and growth by influencing a variety of physicochemical, chemical, and biological aspects of soil. Phosphorus is not readily available in acidic soils rich in Fe and Al. On the other hand, soils with high pH values and large levels of organic matter have lower availability of Mn.
A reduction in soil pH causes a decline in Mo availability. It is widely noted that plants become toxic in acidic soils where Mn and Al’s concentrations are so high. The conversion of water-soluble phosphorus into less soluble forms will be encouraged by high soil pH (pH > 8.0), which will result in lesser availability to plants.
Some soil-borne diseases are impacted by soil reactivity in addition to nutritional factors. Neutral to alkaline soil conditions favor illnesses like potato scab and tobacco root rot, and lowering the pH of the soil (acidic soil reaction) can prevent these diseases.
7. Biotic Factors
Several biotic factors influence plant nutrition and growth as well as the possibility of lower crop yields. Greater vegetative growth and improved environmental conditions may be promoted by heavier fertilizer for some disease-causing pathogens. Increased disease incidence may also be caused by nitrogen imbalances in soils.
Sometimes specific bugs may demand additional fertilizer. When viruses and nematodes damage the roots of some crops, less water and nutrients are absorbed, which slows plant growth.
Weeds are another significant element that significantly slows down plant growth because they compete with plants for moisture, nutrients, sunlight, and other biochemical components known as allelopathy. It’s well known that weeds create and release toxic compounds into the environment around their roots.
8. Provision of Nutrient Components
The nutritional elements—nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, boron, copper, zinc, iron, manganese, molybdenum, etc.—makeup about 5–10% of the dry weight of plants. These necessary nutrients and other substances that are good for plant growth are primarily found in soil.
9. Absence of Growth-Inhibiting Compounds
Toxic substances, such as greater concentrations of nutritional elements (Fe, Al, and Mn), and specific organic acids (lactic acid, butyric acid, propionic acid, etc.), can limit or hinder the growth and development of plants.
In addition to these, hazardous compounds are also produced in soils by waste products from mines and metallurgical operations, sewage systems, pesticides, animal and poultry farms, rubbish collection, paper mills, etc., which ultimately influence plant development and nutrition.
3 Abiotic Factors Affecting Plant Growth
Topography, soil, and climatic conditions are examples of abiotic elements that have an impact on plant growth and development. The degree to which the genetic factor is expressed in the plant is determined by these environmental non-living elements as well as biotic variables.
A nonliving or abiotic component, topography describes the “lay of the land.” It contains the earth’s physical characteristics, such as the height, slope, and topography (flat, rolling, hilly, etc.), as well as mountain ranges and water bodies.
By affecting the differential incidence of solar energy, wind speed, and soil type, a slope’s steepness has an impact on plant development. The temperature impact is the main mechanism by which the height or elevation of the land at the level of the sea surface affects plant growth and development.
This abiotic factor’s link to temperature is similar to the separation between the equator and the polar regions. In dry air, every 100 meters of elevation results in a 10C drop in temperature.
The soil is the topmost part of the earth’s surface where plants can grow. Rock that has been eroded, mineral nutrients, decomposing plant and animal matter, water, and air make up the soil. The topic of soil and climatic adaptation or requirement of crops covers this abiotic component, which is also crucial in crop production.
The majority of plants are terrestrial in the sense that their roots, through which they take up water and nutrients, attach them to the earth. However, epiphytes and floating hydrophytes can survive without soil.
Depending on natural adaptation, changes in the physical, chemical, and biological characteristics of the soil have different effects on plant growth and development.
The physical and chemical features of the soil have distinct direct effects on plant growth and agricultural output.
Earthworms, insects, nematodes, and microorganisms like bacteria, fungi, actinomycetes, algae, and protozoa are among the biological components of living beings in soil.
These organisms aid in enhancing soil aeration, tilth (the breaking and powdering of soil lumps), nutrient availability, water permeability, and soil structure.
The term “edaphic factors of the plant environment” refers to the physical and chemical characteristics of the soil.
The bulk density, soil structure, and soil texture are examples of the physical features of soil that impact how much water the soil can hold and supply, while the pH and Cation Exchange Capacity (CEC) of the soil are examples of the chemical properties that affect how many nutrients the soil can supply.
It is now understood that this abiotic component—soil—is not fundamental to plant growth. Instead, the nutrients in the soil are what cause plants to grow and provide them the ability to finish their life cycle.
The climatic factors which affect plant growth include:
In nature, these elements interact with one another and have an impact on one another. The most important variable in this interaction in a controlled environment, such as a nursery or open field seed bed, is temperature.
A plant has the innate capacity to adjust its level of activity in response to environmental factors, such as at particular temperatures and humidity levels. When conditions are too hot, too cold, too dry, or too humid, the growth of the plant will stop, and if the situation continues, the plant may perish.
Therefore, the ability of a plant to develop and the health of a plant, in general, are strongly influenced by environmental factors. A healthy plant can reproduce and grow if these conditions are well-controlled.
The percentage of water vapor in the air at a specific temperature is known as humidity, also known as relative humidity. This indicates that at a relative humidity of 20%, suspended water molecules will make up 20% of any given volume of air.
The amount of humidity is particularly crucial for the plant to continue its metabolic processes at the proper rates. For seeds and cuttings, the ideal relative humidity for propagation is between 80% and 95%; for budding, grafting, and seedbed techniques, it is around 60% outdoors.
Higher relative humidity speeds up the germination of seeds and cuttings. On steamy summer days, the humidity level frequently drops below 55% in warm, dry places, making budding and grafting more sensitive and needs careful observation.
Only in a balanced environment with adequate levels of both oxygen (O2) and carbon dioxide (CO2) can plants grow and thrive. Both O2 and CO2 are used by the processes of respiration and photosynthesis to support the growth and development of the plant.
The ambient air movement is adequate to aerate plants when they are in the open, such as in seedbeds or beneath shade cloth. Ventilation becomes crucial in certain types of constructions, including tunnels. Tunnel ventilation removes warm air containing CO2 produced by plants, keeping the environment balanced.
For growth to occur, light is a necessity for all green plants. The majority of plant species enjoy growing in direct sunshine, however, certain species prefer growing in the shade where they receive indirect sunlight.
Light is necessary for photosynthesis, and the wavelength of the light determines its quality, which also affects germination and flowering.
Plants grown in protected environments, such as greenhouses and shade houses, need enough light for the photosynthetic process. The plant exhibits signs of growth retardation if it does not receive enough light, which may be caused by shade or overcrowding.
Red light with a wavelength of 660 nanometers (nm) is used in chambers to promote the germination of some types of seeds in seedlings.
Fluorescent tubes supply the blue light needed for photosynthesis after germination, while incandescent globes are frequently utilized as an artificial source of red light for the same reason. The use of these lights is extensive, and they are left on as long as feasible. It is not unusual to have lights on seven days a week, 24 hours a day.
Since light cannot reach deeply into the soil, the depth at which light-sensitive seeds are sown also affects how long it takes for seeds to germinate. Therefore, seeds that are sensitive to light should be planted shallower than seeds that are not.
Lack of or insufficient light results in the production of weak, low-quality seedlings. These seedlings exhibit extreme lengthening or etiolation.
Plants may get heat injury if heat and light, which raise the temperature, are not appropriately regulated. 29°C is the optimum temperature for propagation, and it needs to be regularly watched.
The temperature in propagation chambers is frequently kept at this optimal level by heating and cooling systems. By wetting the trays and dampening the floor, heat is also employed to raise the humidity in the chambers.
With climate change having a major impact on temperature, this factor is the most important in plant growth.
For seeds to germinate and plants to grow healthily, moisture is necessary.
A plant’s roots can become suffocated by too much water, which can lead to illnesses including root rot, damping off, and collar rot. All plants suffer damage from drought, which is the other extreme, although cuttings and young seedlings are more vulnerable.
For seed germination to result in strong, healthy seedlings, and for seedlings to develop into strong, healthy plants, a uniform, and consistent water supply is necessary.
The qualities of the growing medium govern the type and quantity of water that the plant will be able to absorb in all propagation techniques. A good medium has a low saline level, enough water holding capacity (50–60%), the ability to make water freely accessible to the plant, and the capacity to let lateral water circulation.
The seed and later seedling stage must be kept in a medium that has been wetted to field capacity, which is the greatest quantity of water that a specific soil can retain, for the seed to germinate.
2 Internal Factors Affecting Plant Growth
- Growth Regulators
Plants need nutrition as the raw material for growth and development. Plants get their energy from nutrients, which is crucial for differentiation after embryonic growth. The ratio of nitrogen to carbohydrates determines the type of plant growth.
When they are present in high concentrations, the ratio of carbohydrates to nitrogen drives wall thickening. In this case, less protoplasm is generated. When the carbohydrate-to-nitrogen ratio is low, a thin, squishy wall is generated. This results in the formation of additional protoplasm.
2. Growth Regulators
Plant hormones known as growth regulators are in charge of the growth and development of the plant. Growth regulators are produced by live protoplasm and are crucial for each plant’s growth and development. Several phytohormones and a few synthetic compounds are growth regulators.
- Abscisic Acid (ABA)
During a plant’s growth and development, auxins encourage stem elongation. Auxins encourage the development of apical buds while inhibiting the growth of lateral buds. Apical dominance is the term for the circumstance. Indole acetic acid (IA) is an example.
An endogenous plant growth regulator is gibberellin. Gibberellin stimulates stem elongation, which leads to plant growth. Gibberellin acid is frequently referred to as an “inhibitor of an inhibitor” due to its characteristic.
Gibberellins assist break seed dormancy and encourage seed germination. They also help long-day plants blossom. Gibberellins assist plants overcome their inherited dwarfism by causing parthenocarpy. Gibberellins help boost sugarcane stem development, which increases sugar yield.
By promoting cell division during mitosis, cytokinins can promote cell division. Cytokinins are produced by humans as well as being found naturally in plants. Cytokinins encourage plant development by increasing mitosis. The development of shoots, buds, fruits, and seeds is aided by cytokinins.
Only a plant hormone called ethylene exists in gaseous form. It only required a tiny amount. Ethylene aids in the opening of flowers and stimulates or controls the ripening of fruit in plants.
E. Abscisic Acid (ABA)
The abscission of plant leaves and fruits is encouraged by abscisic acid. Abscisic acid is produced in terminal buds throughout the winter to limit plant development. It instructs the scale development of leaf primordia. This process serves to keep the dormant buds safe throughout the winter.
4 Soil Factors Affecting Plant Growth
- Mineral Composition
- Soil pH
- Soil Texture
- Organic Matter
1. Mineral Composition
The soil’s mineral makeup aids in predicting how well it will hold onto plant nutrients. The quality of the soil can be improved by using the right fertilizers and manures.
2. Soil pH
The pH of the soil contributes to keeping the soil’s nutrients available. The ideal pH range for soil fertility is in the range of 5.5-7.
3. Soil Texture
Minerals of various sizes are in charge of preserving the soil’s structure. Because it can hold onto more nutrients, clayey soil functions as a nutrient reservoir.
4. Organic Matter
A source of nitrogen and phosphorus is organic materials. These can be turned into minerals and given to plants.
2 Genetic Factors Affecting Plant Growth
The chromosomes, those cellular structures inside the nucleus that, under a microscope, look as coiled constricted threads or rod-like substances at a particular stage of cell division known as mitosis, are where the genes are located.
A chromosome’s number, size, and shape—known as its karyotype—vary from one species to another.
The physical foundation of heredity is thought to be the chromosomes.
They exist alone in haploid (1N) sexual gametes, in pairs (2N), in triplicates (3N), in the triploid endosperm cells, and numerous sets in the polyploid cells. They also exist singly in haploid (1N) gametes.
Human body cells have 46 diploid (2N) chromosomes, compared to 24 in tomatoes, 20 in corn, and 14 in garden peas.
37,544 genes have been found in the rice genome, according to a 2005 paper published in the journal Nature (436:793-800, August 11, 2005).
An organism’s entire set of haploid chromosomes, or genome, contains all of its genes.
For instance, whereas corn (maize) has 20 diploid chromosomes while rice has 24, they are both distinctly different creatures.
However, diversity or identicality is not solely a function of chromosomal count.
The different sizes and shapes of individual chromosomes mean that two animals with the same number of chromosomes might nevertheless be different from one another.
Additionally, they may differ in the number of genes, the spacing between genes in each chromosome, and the chemical and structural makeup of these genes.
And finally, each organism has a unique genome.
Although genetic variables mostly come from the cell’s nucleus and regulate how phenotypes are expressed, there are some cases of cytoplasmic inheritance where traits are passed on to the progeny through the mother’s cytoplasm.
DNA is found in some cytoplasmic organelles, including the plastids and mitochondria.
The use of male sterile lines in the hybridization of corn and rice has taken advantage of this.
Detasseling, the physical removal of maize tassels, and emasculation, the manual removal of the immature anther from a bud or flower, have both been made less expensive thanks to this approach.
However, there are instances where the gene or genotype is naturally altered, creating a new character.
Although mutations are random and the consequence of a change within a plant’s cells, they can occasionally be brought on by extreme cold, temperature changes, or insect attacks.
If the mutation happens at the growth point, entire shoots may be altered when that cell multiplies and gives rise to entire cell lines. Sometimes the mutation is undetectable since the features are not passed on from the cell where they arose.
When two or more plants or plant sections co-exist with genetically different tissues, the situation is referred to as a chimera. For example, some plants, including chrysanthemums, roses, and dahlias, are prone to generating chimeral flowers, where the flowers have sections of different colors. Chimeras are typically the starting point for variegated plants.
As explained above there are a number of factors that affect the growth of plants. These factors are to be carefully looked into as we plant trees in our quest to remediate Earth.
What is the most important factor for plant growth?
The most significant element influencing plant growth is temperature as the temperature rises, growth quickens but, too much temperature would lead to the drying of the plant and consequently the loss of the plant.
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A passion-driven environmentalist by heart. Lead content writer at EnvironmentGo.
I strive to educate the public about the environment and its problems.
It has always been about nature, we ought to protect not destroy.