Dr. Sarita Srivastava Chaudhary Mahadeo Prasad Degree College Allahabad

 Development: is a series of change which an organism goes through in his life cycle.  Development is associated with morphogenesis and differentiation  During growth  New cells are added by cell division  Organism grows in size  Increase in weigh  Protoplasm multiplicates  Irreversible permanent increase in volume takes place

Growth and Development Definition Definition- Growth: permanent and irreversible change in size of the cell, organ or whole organism usually accompanied with increase in dry weight.

Types of Plant Growth 1. Determinate growth : As you grow and develop from childhood you get taller and bigger overall. But at some point you reach a maximum height. This type of limited growth is called determinate growth. What it means is that once you have reached your maximum height (which is determined by your genetics), you can't grow any taller. This is something that you have no control over. 2. Indeterminate growth: Plants, unlike animals, have indeterminate growth. This means that they can continue to grow taller as long as they are alive. Most plants tend to slow their growth at some point, but as long as they wish to keep growing they may do so. All plants experience what is called primary growth. Primary growth is the upward growth of the stem and the downward growth of the roots. It is the type of growth that makes a plant longer. Some plants experience an additional type of growth called secondary growth. This occurs in plants known as dicots, such as trees, shrubs, and vines. Secondary growth is the outward or lateral growth of a plant, which makes it thicker and wider. Dicots need secondary growth because they tend to grow taller than other plants and need the extra support. Without secondary growth, a tall pine tree would be just like a very long blade of grass.

Growth involves meristematic changes 1.Cell division : occurs due to meristems, apical intercalary and lateral 2.Cell enlargement: 3.Cell maturation

 Cell is metabolically highly active  Cellular mass of cell increases  Replication of genetic material takes place  Growth basically due to the mitotic cell division  Mitochondria and chloroplast duplicate on their own  Two daughter cells are formed which are half the size of the mother cell  These cells proceed for cell enlargement

 Cells increase in size due to vacuolation i.e. absorption of water  The central vacuole pushes the cytoplasm to the periphery of cell  The cell wall becomes thin  New wall material is being synthesized to cope up with the cell enlargement  It is said that cell enlargement is governed by osmosis  DPD=OP-TP  Wall pressure is reduced in the vacuolating cells due to increased plasticity of cell walls this results in absorption of water from the neighboring cells  Cell enlargement is associated with absorption of water, synthesis of new cytoplasm and cell wall material

 Development of specialized mature tissues  E.g. meristematic cells of leaf epidermis differentiates to form:  Guard cells  Trichomes  Glands  Epidermal cells  Cell differentiation depends upon the growth factors

Growth Curve is Sigmoid Growth Curve : Lag Phase Log Phase Steady Phase

An auxanometer (Gr. auxain, "to grow" + metron, "measure") is an apparatus for measuring increase or rate of growth in plants.plants A crescograph is a device for measuring growth in plants. It was invented in the early 20th century by Sir Jagadish Chandra Bose - a Bengali polymath, physicist, biologist, botanist, archaeologist.plantsJagadish Chandra Bose

Factors affecting growth

 Light :  Etiolation  Photomorphogenesis  Seedling growth, seed germination, flowering  Temperature:  thermoperiodicity-fluctuation in temp affectin growth  25 ˚C day temp-12˚C night  Water: water stress stops growth

 C/N ratio  More nitrogen :  more protoplasm,  less mechanical tissues,  vigorous vegetative growth,  shoot is large in compared to roots  leaves are large and soft  Succulent and dark green in colour  Less nitrogen and more carbohydrate favors more wall synthesis, less protoplasm and more roots as compared to shoot

 The genes of an individual determines its type Hormonal factors: Growth is regulated by growth hormones

 What is difference between Growth hormones and growth regulators  Definition of Growth hormones:

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