Environmental Factors – Growth and Development

Environmental Factors

 Key Concepts

1. Growth and development
2. Factors affecting growth and development
3. External factors in plants
   1. Light
   2. Temperature
   3. Water
   4. Mineral nutrients
4. Internal factors in plants- Auxin, Gibberellin
5. Growth and development in humans

Introduction

Have you noticed that all living organisms grow in size. But have you ever thought how a do they grow? 

Explanation

Growth refers to the increase in size of a body or organs, development refers to physiological functional maturation of the organism 

Morphogenesis is a process of the development of shape and structure of an organism; differentiation is a process of change in cells, tissues, organs to carry out different function 

Environmental factors affecting plant growth and developments 

Plant growth ,development are influenced by the environment .The environmental factors are of two types internal and external factors  

external factors include light,temperature water,humidity and nutrition . 

internal factors include plant hormones such as auxin,gibberillins  

Role of light in growth of a plant   

Light is most important extanal factor which helps in the process of photosynthesis ,light intensity directly influence on the manufacture of plant food,stem elongation  

Role of temperature in plant growth  

Some of the plants grow in cold climate and some in hot climate .all metabolic activities of plants are directly affected by temperature variation,low temperature causes injury to plant due to chilling or freezing r very high temperature will affect growth of the plant  

Role of water  in plant growth  

Plant obsorbs water through roots , and uses it for the process of photosynthesis.All the metabolic activities takes place, excess water is lost through during transpiration  

Role of mineral nutrients  in plant growth  

All the metabolic activities required inorganic nutrients ,plant growth is adversely affected by deficiency of nutrients ,other than light, water, and a perfect temperature, organisms need special nutrients to support their food-making process and metabolism, which ultimately boosts growth 

Internal Growth Factors 

Substance produced by plant body, affects growth of the plant, called plant hormones or phytohormes or growth hormones  

Growth regulators are chemical substance which promote, inhibit growth and development in plants  

AUXIN  

Auxin promote growth,generally produced by the growing apex of stem and root of the plants ,helps in the elongation of shoot and root tips behind apical meristems  

Gibberellin 

Gibberellins  helps in elongation of stems genetically dwarf plants , it breaks seed dormancy In plants, it is produced in embryos, roots, and young leaves and it enhances growth