Plant Growth Auxin
Growth
Growth and development are the most fundamental characteristics of all living organisms. The physiological definition of growth is “An irreversible change in the organism, organ or cell is called growth”, which includes increase in mass weight or volume of living organism, it leads to development in plants.
REGION OF GROWTH:
Growth region is located at extreme apices of root, stem, leaf where we make out meristematic tissue. In addition to above, the region where intercalary and lateral meristem is present is also considered as growth region.
PHASES OF GROWTH:
Growth is a complex process where the dividing cell pass through three phases:
1. Cell division
2. Cell elongation
3. Cell differentiation
Cell Division:
The meristematic cells are thin walled and densely cytoplasmic which shows continuous mitotic divisions
Cell Elongation:
The daughter cell formed by the division of meristem undergo enlargement both length wise and diameter wise and leads to overall growth of organ.
Cell Differentiation;
As the cells enlarge, they gradually attain permanent shape and size called maturation process. The cells become differentiated into different organs and the mature cell maybe dead or living.
GROWTH CURVE:
Growth of a plant or any of its organs is not uniform. Instead, it passes through the following stages: * Lag phase:
It is the initial stage in growth where growth rte is very slow, because it is formative stage. * Log phase:
It is the stage where growth occurs in rapid rate due to maximum physiological activity in the cells and it is also known as exponential stage * Stationary phase;
This phase is characterized y decreasing growth because the physiological activity of cells also slows down. In other words, the size of the body would have reached an optimum volume to surface ratio and this ratio is maintained constant from then onwards. “if we plot growth in terms of dry weight against time, we obtain on S-shaped curve and the total
Growth and development are the most fundamental characteristics of all living organisms. The physiological definition of growth is “An irreversible change in the organism, organ or cell is called growth”, which includes increase in mass weight or volume of living organism, it leads to development in plants.
REGION OF GROWTH:
Growth region is located at extreme apices of root, stem, leaf where we make out meristematic tissue. In addition to above, the region where intercalary and lateral meristem is present is also considered as growth region.
PHASES OF GROWTH:
Growth is a complex process where the dividing cell pass through three phases:
1. Cell division
2. Cell elongation
3. Cell differentiation
Cell Division:
The meristematic cells are thin walled and densely cytoplasmic which shows continuous mitotic divisions
Cell Elongation:
The daughter cell formed by the division of meristem undergo enlargement both length wise and diameter wise and leads to overall growth of organ.
Cell Differentiation;
As the cells enlarge, they gradually attain permanent shape and size called maturation process. The cells become differentiated into different organs and the mature cell maybe dead or living.
GROWTH CURVE:
Growth of a plant or any of its organs is not uniform. Instead, it passes through the following stages: * Lag phase:
It is the initial stage in growth where growth rte is very slow, because it is formative stage. * Log phase:
It is the stage where growth occurs in rapid rate due to maximum physiological activity in the cells and it is also known as exponential stage * Stationary phase;
This phase is characterized y decreasing growth because the physiological activity of cells also slows down. In other words, the size of the body would have reached an optimum volume to surface ratio and this ratio is maintained constant from then onwards. “if we plot growth in terms of dry weight against time, we obtain on S-shaped curve and the total