Plant growth and Development In One Shot – JEE/NEET/Class 11 th Boards
The name of the chapter itself suggests plant growth so we are going to talk about plant growth. The
thickness in some of the plants like dicots and some gymnosperms it is indeterminate type or open type.
The growth is due to the increase in the protoplasmic content of the cell which can not be measured as
a result. We measure the growth indirectly by studying the change occurring due to. The increase. In
the. Change in the amount of. The cell size. And the volume of the cells is increasing because of which
the cell will divide resulting in the increased in the number of cells and thus the body grows.There are
three typical phases of growth including zone of meristem, phase of elongation and phase of
maturation. Phase of growth is characterized by increased evacuation and increase in cell wall thickness.
The cell is only having primary cell wall which is very thin and flexible but as the cell is young it expands
gives space for more deposition of secondary cell wall.
There are two ways to measure the growth rate one type of growth rate is arithmetic and the second is
geometric growth rate. If the number of trophies are increasing then this increase is known as
arithmetic in plants also growth can be arithmetic type now what happens in arithmetic growth see if
there is one cell right this is the cell which is actively dividing which wants to divide. The graph of
arithmetic growth is a linear straight line but not passing through the center as it is having a Intercept a
y-intercept whose value is equivalent to l naught clear so this much you have to remember for
arithmetic growth I hope you will remember the second type of growth is geometric also known as
exponential growth. Conditions of growth are very important that how and when you can increase the
rate of growth for that if I talk about conditions of growth you should provide proper light and ample
amount of water should be given to the plant. A time will come when the nutrients will drain out and
because of which then the growth will become stagnant creating a s-shape sigmoid growth curve.
Usually development is straight straight in animals development do not show any deviation it is straight.
In some plants they may show deviation from the path of development. Plasticity deviation can be in
any organ of the plant maybe in leaves maybe in flowers or flowers. Plasticity is known as heterophylli
hetero means different philly means leaf. Plastic plasticity is deviation in terms of development simple as
that only observed in plants not in animals. Plant growth is regulated by hormones secreted by the plant
body. There are five hormones discovered in plant body all have been discovered accidentally and out of
the five hormones we can divide them on the basis of their functions they performed as positive
hormones and negative hormones. Augsin is one of the plant growth promoting hormone which was
discovered by charles darwin and his son while working on the colluptile of canary grass. Negative
hormones are those which inhibit the growth and metabolism of plant body so under positive growth
hormones we have three auxin auxins are better tryptophan derivatives. A fellow darwin thought that
maybe in the presence of the light the tip of the collectile is capable of synthesizing some growth
stimulating hormone which is causing unequal growth on tip of column tile. He concluded that even
after giving light the decapitated seedling is not showing bending because the tip is absent this means
the hormone is synthesized on the tip the light as a stimulus is perceived by the tip. The term auxin is
derived from the greek word called auxin which means to grow. It was first isolated from human urine
and synthesized in human body as well however it is of no use in our body so it is passed out through
urine as a waste. The hormone has been extensively used in horticultural and agricultural practices.
The name of the chapter itself suggests plant growth so we are going to talk about plant growth. The
thickness in some of the plants like dicots and some gymnosperms it is indeterminate type or open type.
The growth is due to the increase in the protoplasmic content of the cell which can not be measured as
a result. We measure the growth indirectly by studying the change occurring due to. The increase. In
the. Change in the amount of. The cell size. And the volume of the cells is increasing because of which
the cell will divide resulting in the increased in the number of cells and thus the body grows.There are
three typical phases of growth including zone of meristem, phase of elongation and phase of
maturation. Phase of growth is characterized by increased evacuation and increase in cell wall thickness.
The cell is only having primary cell wall which is very thin and flexible but as the cell is young it expands
gives space for more deposition of secondary cell wall.
There are two ways to measure the growth rate one type of growth rate is arithmetic and the second is
geometric growth rate. If the number of trophies are increasing then this increase is known as
arithmetic in plants also growth can be arithmetic type now what happens in arithmetic growth see if
there is one cell right this is the cell which is actively dividing which wants to divide. The graph of
arithmetic growth is a linear straight line but not passing through the center as it is having a Intercept a
y-intercept whose value is equivalent to l naught clear so this much you have to remember for
arithmetic growth I hope you will remember the second type of growth is geometric also known as
exponential growth. Conditions of growth are very important that how and when you can increase the
rate of growth for that if I talk about conditions of growth you should provide proper light and ample
amount of water should be given to the plant. A time will come when the nutrients will drain out and
because of which then the growth will become stagnant creating a s-shape sigmoid growth curve.
Usually development is straight straight in animals development do not show any deviation it is straight.
In some plants they may show deviation from the path of development. Plasticity deviation can be in
any organ of the plant maybe in leaves maybe in flowers or flowers. Plasticity is known as heterophylli
hetero means different philly means leaf. Plastic plasticity is deviation in terms of development simple as
that only observed in plants not in animals. Plant growth is regulated by hormones secreted by the plant
body. There are five hormones discovered in plant body all have been discovered accidentally and out of
the five hormones we can divide them on the basis of their functions they performed as positive
hormones and negative hormones. Augsin is one of the plant growth promoting hormone which was
discovered by charles darwin and his son while working on the colluptile of canary grass. Negative
hormones are those which inhibit the growth and metabolism of plant body so under positive growth
hormones we have three auxin auxins are better tryptophan derivatives. A fellow darwin thought that
maybe in the presence of the light the tip of the collectile is capable of synthesizing some growth
stimulating hormone which is causing unequal growth on tip of column tile. He concluded that even
after giving light the decapitated seedling is not showing bending because the tip is absent this means
the hormone is synthesized on the tip the light as a stimulus is perceived by the tip. The term auxin is
derived from the greek word called auxin which means to grow. It was first isolated from human urine
and synthesized in human body as well however it is of no use in our body so it is passed out through
urine as a waste. The hormone has been extensively used in horticultural and agricultural practices.
