Plant Growth - Botany, Class 11 Video Lecture

plant growth and development growth
growth is one of the most fundamental
and conspicuous characteristics of
living organisms it is defined as an
irreversible permanent increase in size
of an organ or its parts or even of an
individual cell growth is accompanied by
metabolic processes that occur at the
expense of energy germination and growth
of a bean seedling is illustrated here
growth in plants is unique as they
retain the capacity for unlimited growth
throughout their life
growth rate arithmetic growth rate
geometric growth rate and embryonic
development involving arithmetic and
geometric growth rate our illustrator
than the diagram in arithmetic growth
following mitotic cell division only one
daughter cell continues to divide while
the other differentiates and matures in
geometrical growth both the progeny
cells following mitotic cell division
retain the ability to divide and
continue to do so during the development
of an embryo both types of growth rate
are involved this transforms a single
cell disease I chord into a
multicellular organism
development besides growth and
differentiation a plant also undergoes
development development is a sequence of
events that occur in the life history of
a cell organ or organism which includes
growth differentiation maturation and
senescence the sequence of which is
shown in the diagram attic
representation thus during its life
cycle from germination of the seed
through growth maturation flowering seed
formation and senescence
plant growth regulators plant growth
regulators or plant hormones are small
simple molecules of diverse chemical
composition in low concentrations plant
hormones regulate growth differentiation
and development by promoting or
inhibiting the same auxins are plant
hormones which maintain apical dominance
apical dominance is a phenomenon by
which presents of apical bud does not
allow the nearby lateral buds to grow
decapitation of the apical shoot tip
results in the growth of lateral buds as
shown in the diagram
a comparative account of plant growth
regulators a comparative account of
plant growth regulators namely oxen
gibberellin cytokinin abscisic acid and
ethylene on plant development as tablet
adhere a positive sign indicates the
involvement of the plant hormone in the
given category of plant development and
vice versa
photoperiodism the response of plans to
periods of day or night is termed as
photoperiodism three different types of
plants are shown here depending on
photoperiodism long day plants require
the exposure to light for a period
exceeding a well-defined critical
duration before the flowering is
initiated short day plants require the
exposure to light for a period less than
a well-defined critical duration before
the flowering is initiated day-neutral
plants show no correlation between the
exposure to light duration and induction
of flowering response