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Plant Growth and Development - Coggle Diagram
Plant Growth and Development
Two classes of meristems:
Vegetative meristems
:
Give rise to plant parts such as
stems, leaves
and
roots.
Reproductive meristems
:
Give rise to flowers that ultimately will develop into
fruits
and
seeds.
Condition for Growth
Water:
◦ Provides the medium for enzymatic activities needed for growth
Oxygen:
◦ Helps in releasing energy which is utilised in growth
activities
Nutrients:
◦ Required by plants for synthesis of protoplasm
Temperature:
◦ A range of optimum temperature is also necessary for growth in a plant
The Angiosperm Flower
Male and female structures usually occur
together in
same individual flower
◦ Composed of Whorls
:check: Outermost - Sepals (Calyx)
:check: Second - Petals (Corolla)
:check: Third - Stamens (Androecium)
:check: Anther
:check: Fourth - Carpel (Gynoecium)
:check: Stigma, Style, Ovary
Angiosperm Reproduction
Pollination
-Transferring pollen to stigma
◦ Self-Pollination
◦ Pollinators often drawn to nectar
◦ Wind (plants grow close together to ensure pollination)
Fertilization:
Double fertilization - two sperm cells used forming embryo and endosperm
Seeds:
Germination - Resumption of metabolic activities that leads to growth of mature plant
Seed Form and Function:
:check: Seeds are the
reproductive structure
that contains a plant embryo.
:check: Seeds
store food
that the
embryo
uses for germination
:check: Seeds have a protective coat (Cotyledon) :check: Seed may contain
one (monocot)
or two (dicot) seed coats.
Fruit:
During seed formation, flower ovary begins to develop into fruit
Germination:
Resumption of metabolic activities and
growth often trigged by water
Plant Hormones:
Differentiation in plants is largely reversible.
Photoperiodism and Dormancy
Photoperiodism
:check:
Short day plants
: require a relatively short day length than the critical period for flowering
:check:
Long day plants
: require a relatively longer day length than the critical period for flowering
:check:
Day neutral plants
: The flowering response in these plants remain unaffected by the length of the day
Chemical Basis of Photoperiodism
:
Phytochromes – helps maintain the circadian rhythm
Circadian rhythm
: Internal clock that measures the length of night and day
Controlled by: :check: Endogenous (internal) factors and/or
:check: Exogenous (external) factors
Tropisms
Phototropism
- Growth towards directional
sources of light
Tropisms
- Growth responses of plants to
external stimuli
Gravitropism
- Stems grow upward and roots
downward
Thigmotropism
- Response of plants to touch
Ageing, senescence, and death in plants
Ageing
:
:check: It is sum total or metabolic changes that
occur in plant or its parts.
:check: Ageing is a permanent feature of all living
organisms
Senescence
:
:check: Refers to all collective, progressive and deteriorative process which leads to complete loss of organization and function.
:check: Occurs as a result of ageing and leads to
death.
Death
:
:check: Death is a permanent feature of all living
organisms.