Factors Affecting Plant Growth:
- Plant Hormones
- Environmental Condition
- Soil Fertility
- Control Measures
1.Plant Growth Regulators:
Tree growth regulators (also called plant hormones) are numerous chemical substances that profoundly influence the growth and differentiation of plant cells, tissues and organs. Plant growth regulators function as chemical messengers for inter-cellular communication .There are currently five recognized groups of plant hormones: auxins, gibberellic acid cytokinins, abscisic acid (ABA) and ethylene. They work together coordinating the growth and development of cells. Ethylene is mainly involved in abscission and flower senescence in plants and is rarely used in plant tissue culture. In addition to the five principal growth regulators, two other groups sometimes appear to be active in regulating plant growth.Types of Plant Growth Regulator:
- Auxins
- Cytokinins
- Gibberellins
- Abscisic Acid
- Ethylene
Functions of plant hormones :
Auxins: Auxin function is to stimulate the cell elongation and influence a host of other developmental responses, such as root initiation, vascular differentiation, tropic responses, apical dominance and the development of auxiliary buds, flowers and fruits. Auxins are synthesized in the stem and root apices and transported through the plant axis. The principal auxin in plants is indole-3-acetic acid (IAA). Several other indole derivatives, all as precursors to IAA, are known to express auxin activity, probably by converting to IAA in the tissue. Auxins in plant tissue culture are used to induce callusA from explants , and cause root and shoot morphogenesis . Auxins are often most effective in eliciting their effects when combined with cytokinins.
Cytokinins: Cytokinins are able to stimulate cell division and induce shoot bud formation in tissue culture. They usually act as antagonists to auxins. (Cytokinins are N6 substituted derivatives of the nitrogenous purine base adenine.) Cytokinins most used in tissue culture include zeatin, adenine, 6-(g,g-dimethylallylamino)purine (2 iP) and kinetin. Cytoknins often inhibit embryogenesis and root induction.
Gibberellins: The main effect of gibberellins in plants is to cause stem elongation and flowering. They are also prominently involved in mobilization of endosperm reserves during early embryo growth and seed germination. Gibberellins are an extensive chemical family based on the ent-gibberellane structure. There exit over 80 different gibberellin compounds in plants but only giberrellic acid (GA3) and GA4+7 are often used in plant tissue culture. In tissue culture, gibberellins are used to induce organogenesis, particularly adventitious root formation.
Abscisic Acid: Function of Abscisic (ABA) in plants is to regulate the seed germination, inducing storage protein synthesis and modulating water stress. In plant tissue culture, it is used to help somatic embryo-genesis, particularly during maturation and germination.
Ethylene: Ethylene is a simple gaseous hydrocarbon with the chemical structure H2C=CH2. Ethylene is apparently not required for normal vegetative growth. However, it can have a significant impact on development of root and shoots. Usually, ethylene is not used in plant tissue culture.
Cytokinins: Cytokinins are able to stimulate cell division and induce shoot bud formation in tissue culture. They usually act as antagonists to auxins. (Cytokinins are N6 substituted derivatives of the nitrogenous purine base adenine.) Cytokinins most used in tissue culture include zeatin, adenine, 6-(g,g-dimethylallylamino)purine (2 iP) and kinetin. Cytoknins often inhibit embryogenesis and root induction.
Gibberellins: The main effect of gibberellins in plants is to cause stem elongation and flowering. They are also prominently involved in mobilization of endosperm reserves during early embryo growth and seed germination. Gibberellins are an extensive chemical family based on the ent-gibberellane structure. There exit over 80 different gibberellin compounds in plants but only giberrellic acid (GA3) and GA4+7 are often used in plant tissue culture. In tissue culture, gibberellins are used to induce organogenesis, particularly adventitious root formation.
Abscisic Acid: Function of Abscisic (ABA) in plants is to regulate the seed germination, inducing storage protein synthesis and modulating water stress. In plant tissue culture, it is used to help somatic embryo-genesis, particularly during maturation and germination.
Ethylene: Ethylene is a simple gaseous hydrocarbon with the chemical structure H2C=CH2. Ethylene is apparently not required for normal vegetative growth. However, it can have a significant impact on development of root and shoots. Usually, ethylene is not used in plant tissue culture.
Importance of Plant Growth Regulators:
Plant hormones are very important in the growth and development of plant. They are formed in different parts of plants at different events. Their shortage in plant may effect the plant development such as plant may look dwarf or no development in shoots of plant. That is why they are very important to the plant proper growth.
2. Environmental Conditions:
Environmental condition such as temperature, humidity, sun light as well as wind effect the plant growth. If conditions are not favorable to the plant growth may have retarded then we have to apply control measures to help out the plant from these unfavorable conditions.
3. Soil Fertility :
Soil is the main source of nutrients as well as water. Soil also give support for roots to anchor the plant within the ground.
If the soil is unable to provide nutrients to plants which it needed then we have to apply Fertilizers to help the plant growth.There are many types of fertilizers which are used on the bases of plant requirements.
4. Control Measures:
Why we need to apply control measures? There are so many factors that effect the plant proper growth such are weed, insets, microorganisms, rodents etc. Firstly we need to identify the factors that affect the plant growth and then we will be able to apply control measures.On the bases of problems that we are dealing with we you different control measures i,e Weedicides for weed, Pesticides for insect pest etc.Many advance farm equipment are used to eradicate the weeds from field as we as for tillage, harvesting, irrigation purpose. Modern agriculture techniques helps the farmer to grow on large area by saving time and energy.
IPM is the term used for Integrated pest management (IPM), also known as integrated pest control (IPC) is a broad-based approach that integrates practices for economic control of pests. IPM aims to suppress pest populations below the economic injury level (EIL).
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