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Floral Initiation F

Floral initiation is the initial step in flower development where a plant transitions from vegetative to reproductive growth. It involves activating genes and forming floral meristems. Environmental cues like vernalization and photoperiodism influence initiation through signal transduction and gene expression. Vernalization exposes plants to cold to induce flowering, while photoperiodism is a plant's response to day and night lengths, categorizing plants as short day, long day, or day neutral.

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380 views20 pages

Floral Initiation F

Floral initiation is the initial step in flower development where a plant transitions from vegetative to reproductive growth. It involves activating genes and forming floral meristems. Environmental cues like vernalization and photoperiodism influence initiation through signal transduction and gene expression. Vernalization exposes plants to cold to induce flowering, while photoperiodism is a plant's response to day and night lengths, categorizing plants as short day, long day, or day neutral.

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Floral Initiation

Group 1
Growth stages of plants
What is floral initiation?

• the initial step in the development of


flowers, where the plant transitions from
vegetative growth to reproductive growth.

• involves the activation of specific genes


and the formation of floral meristems.
How does the initiation of florals occur?

Environmental Perception of Signal


Environmental Gene Expression
Cues Transduction
Signals

Pollination and Floral Organ Formation of Floral


Fertilization Development Meristems
How vernalization and photoperiodism
influence floral initiation?
Vernalization Photoperiodism

- the process of - the response of plants to


accelerating the ability of the relative lengths of dark
flowering in plants by and light period.
exposing them to cold
temperatures
Vernalization

• Originated from latin word, Vernus – “of the spring”.

• It is the induction of the flowering process of the plant by


exposure to the long periods of cold winter or such
conditions.
The artificial method of
vernalization was discovered by a
Russian worker, Trofim Denisovich
Lysenko, in 1928.

In this technique, a cold treatment is


given especially to flower buds, seeds or
seedlings.
T.D. Lysenko
Process of Vernalization

1. First, soak the desired seeds in water


2. Allow it to germinate in processing chamber
3. Then subject it to the chilling treatment
4. Then the moistened seeds are dried
5. Finally the seeds are sown in the fields
Types of Vernalization
Obligate Vernalization

- a cold period is absolutely


required, plants will not flower without cold
Example: Biennial Plants (cabbage)

Facultative Vernalization

- a cold period is merely


beneficial, plants can benefit but cold
treatment is not absolutely required.
Example: Winter Annual Triticale
Effect of Vernalization
Photoperiodism
• The physiological reaction of plants to the length of
day and night.

Plants have been classified based on photoperiodic response


into the following categories:

- Short day plants


- Long day plants
- Day neutral plants
- Long-short day plants
- Short-long day plants
Short day plants
- plants that flower when the
photoperiod or day length is
short.

Examples: tobacco, soya beans,


sugarcane, etc.
Long day plants

• plants that flower when the days


are longer than their critical day period.

Examples: lettuce, spinach, potatoes, etc.


Day neutral plants
• plants that produce flowers throughout
the year irrespective of length of light hours
to which they are exposed.

Examples: Sunflowers, peas, tomatoes, etc.


Long-short day plants
• These are short day plants but must be
exposed to long days during early periods
of growth for subsequent flowering
Example: Night Blooming Jasmine

Short-long day plants


• These are long day plants but must be
exposed to short days during early periods
of growth for subsequent flowering
Example: Winter Rye
Structure
of a
Flower
The ABC model of flower development
The End
Members:
Henobla, Avigaile
Gallego, Steven
Loking, Allysa Joyce
Villaver, Christopher

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