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Plant Growth and Development

            IMPORTANT TERMS

Ø  Abscission: Shedding of leaves and fruits from the plant.

Ø  Apical Dominance: Inhibition of the growth of lateral buds in presence of apical bud.

Ø  Antagonistic: Effect of one substance opposite to the other’s activity.

Ø  Bolting: Sudden elongation of a rosette or condensed stem before flowering.

Ø  Determinate Meristem: The meristem which is active only for a short period.

Ø  Dedifferentiation: Refers to the regaining of the capacity to divide by the differentiated cells.

Ø  Development: Refers to the sequence of events that occur in the life history of a cell, organ of organism involving, growth, differentiation, maturation and senescence.

Ø  Differentiation: The qualitative change in terms of structure and functions of newly formed cells.

Ø  Indeterminate Meristem: The meristem involved in open form of growth.

Ø  Phototropism: Tropic movement induced by the direction of light.

Ø  Photoperiodism: Effect of duration of light and dark on flowering.

Ø  Plasticity: Development of different kinds of structures by a plant in response to environment or phases of life.

Ø  Redifferentiation: Refers to the loss of ability to divide by the products of dedifferentiated cells.

Ø  Senscence: The period between reproductive maturity and death of a plant or a plant part.

Ø  Synergistic: Cooperative effect of two or more substances.

Ø  Vernalization: Acquisition or acceleration of the ability to flower by a chilling treatment.

 

ADDITIONAL INFORMATION

Ø  Negative Growth: The term is sometimes used for senescence.

Ø  Etiolation: A phenomenon exhibited by green plants when grown in darkness. Etiolated seedlings are pale elongated and sticky with primary leaves unexpanded and yellow.

Ø  Photomorphogenesis: The control exerted by light over growth, development and differentiation of a plant, independent of photosynthesis. The various photomorphogenic effects are regulated by a photoreversible pigment—phytochrome.

Ø  Phytochrome: A pigment protein complex which exists in two interconvertible forms—Pr form and Pfr form. The Pr form, which is stable in dark, absorbs red light and is instantly changed to Pfr form. The Pfr form absorbs near 730µ and is converted back to Pr form.

Ø  Morphactins: Synthetic growth inhibitors which inhibit the germination of seeds and the growth of seedlings, reduce longitudinal growth of seedlings, reduce longitudinal growth of shoot and the development of leaf blade, reverse apical dominance and promote the growth of lateral buds causing a broom like form of the plant.

Ø  Coconut milk: (Liquid endosperm of coconut) shows cytokinin like activity.

Ø  Ascorbic Acid: Prevents over ripening and browning of cut fruits due to its being anti-oxidant.

Mr. A. KINGSLIN M.Sc, BEd, Phd,(doing)
Post Graduate Teacher in Botany
St. Mary Goretty Hr. Sec School, Manalikarai 
Kanyakumari district





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