Development may be defined as the "progressive appearance of the mature multicellular form of the organism following the fusion of gametes".
The availability of water and oxygen are the essential conditions for seed germination.
Some plants growing in marshy land, show a special type of germination known as vivipary as in Rhizophora, Sonneratia and Heritiera.
Growth, whether it is of a cell, an organism, or a population shows a characteristic S-shaped (sigmoid) growth curve.
The growth of a plant in length wise can be measured by an instrument called Lever auxanometer.
In perennial plants, growth continues throughout their life.
Phytohormones belong to five classes of compounds, namely auxins, gibberellins, cytokinins, abscisic acid and ethylene.
Went coined the term 'auxin.' It was called as Indoleacetic acid (IAA).
It was in 1938 that the crystalline form of gibberellin A was isolated from the culture of the fungus, Gibberella fujikuroi.
Apples, figs and grapes will develop, even without pollination, following a spray treatment of gibberellins.
Cytokinins when acting together with auxins, strongly stimulate mitosis in meristematic tissues.
Abscisic acid influences senescence, abscission and flower initiation.
Ethylene is functional in the ripening of fruits.
At least three or four important morphological or environmental conditions control or influence the initiation of flowers. One of these is called ripeness to flower, that is, the appropriate age or stage of morphological development before flower initiation can occur. Another factor is relative lengths of days and nights, a response called photoperiodism.
Studies on Xanthium and many other plants have shown that leaves are the organs of photoreception.
Vernalization is a term coined by the Russian agronomist Lysenko, to refer to the method of acceleration of the flowering ability of biennials or winter annuals, by exposing their soaked seeds to low temperatures.
Abscission is shedding of leaves, fruits or flowers by a plant, generally due to a change in the hormonal balance.
Plants also show certain movements of their body or body parts in response to changes in the environment.
The stimuli involved in tropic movements are gravity (geotropism), light (phototropism), contact (thigmotropism), water (hydrotropism) and chemicals (chemotropism).
Curvature of fixed plant organs in response to chemicals is called chemotropism.
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