BSC 314 Lecture 5: Growth and Development
26 Jun 2018
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Growth and Development
“Development” and “growth” are sometimes used interchangeably in conversation, but
in a botanical sense they describe separate events in the organization of the mature
plant body.
Development is the progression from earlier to later stages in maturation,
e.g. a fertilized egg develops into a mature tree. It is the process whereby
tissues, organs, and whole plants are produced. It
involves: growth, morphogenesis (the acquisition of form and structure),
and differentiation. The interactions of the environment and the genetic
instructions inherited by the cells determine how the plant develops.
Growth is the irreversible change in size of cells and plant organs due to
both cell division and enlargement. Enlargement necessitates a change in the
elasticity of the cell walls together with an increase in the size and water
content of the vacuole. Growth can be determinate—when an organ or part or
whole organism reaches a certain size and then stops growing—
or indeterminate—when cells continue to divide indefinitely. Plants in general
have indeterminate growth.
Differentiation is the process in which generalized cells specialize into the
morphologically and physiologically different cells described in Table 1 .
Since all of the cells produced by division in the meristems have the same
genetic make up, differentiation is a function of which particular genes are
either expressed orrepressed. The kind of cell that ultimately develops also
is a result of its location: Root cells don't form in developing flowers, for
example, nor do petals form on roots.
Mature plant cells can be stimulated under certain conditions to divide and
differentiate again, i.e. to dedifferentiate. This happens when tissues are
wounded, as when branches break or leaves are damaged by insects. The
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Document Summary
Development and growth are sometimes used interchangeably in conversation, but in a botanical sense they describe separate events in the organization of the mature plant body. Development is the progression from earlier to later stages in maturation, e. g. a fertilized egg develops into a mature tree. It is the process whereby tissues, organs, and whole plants are produced. It involves: growth, morphogenesis (the acquisition of form and structure), and differentiation. The interactions of the environment and the genetic instructions inherited by the cells determine how the plant develops. Growth is the irreversible change in size of cells and plant organs due to both cell division and enlargement. Enlargement necessitates a change in the elasticity of the cell walls together with an increase in the size and water content of the vacuole. Growth can be determinate when an organ or part or whole organism reaches a certain size and then stops growing or indeterminate when cells continue to divide indefinitely.
