Tag: plant growth and development
Questions Related to plant growth and development
Name the plant hormone associated with apical dominance.
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Auxin
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Ethylene
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Cytokinin
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None of the above
- Apical dominance is a phenomenon wherby, the inhibition of the growth of lateral buds occurs due to the terminal bud of a shoot.
- It is caused by the production of IAA (auxin) in abundance by the apical bud.
- This auxin is transported basipetally from the apical bud.
- The auxin causes the lateral buds to remain dormant.
Avena coleoptile test to find out the amount of growth promoting hormones was discovered by
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F W. Went
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LJ.Odum
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K.V Thimann
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F. Skoog
F. W. Went in 1928 used tip of Avena coleoptile. He removed the tip of Avena coleoptile and and placed in on the agar agar block for the definite measured amount of time. Then this agar agar block was placed asymmetrically on the stump, this showed a positive curvature.
The discovery, that during light induced bending of stem the apex produces a diffusible chemical, was made by
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Charles Darwin and Francis Darwin
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Boysen-Jensen and Paal
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Went
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Van Overbeek
A tropism is a growth movement by plant part in the direction of the stimulus. According to Boysen-Jensen, the stimulus for phototropism, growth in response to light, is a diffusible chemical that passes from the tip of the coleoptile. He cut the tip of the coleoptile and the severed tip was reattached through a gelatin disc. The recapitated coleoptile showed bending of stem towards light. Paal continued with Boyse-Jensen work. He said that the tip of coleoptile produces some chemical which travels down and stimulates growth. The light causes the accumulation of that chemical on the shaded side of the coleoptile.
Decapitation i.e. removal of shoot tips in a plant usually results in
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inactivation of lateral buds
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growth of lateral buds
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cessation of plant growth
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yellowing of leaves.
Growth hormone responsible for apical dominance is
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Auxin
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Cytokinin
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Gibberellin
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Ethylene
Apical dominance is a phenomenon in which central stem is dominant and lateral stems are suppressed. It is due to plant hormones produced in the tip of the shoot. Auxin hormone is responsible for apical dominance and cytokinin hormone is responsible for breaking the apical dominance.
Substances which originate at the tip of stem and control growth elsewhere are
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Enzymes
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Hormones
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Vitamins
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None of the above
A chemical substance produced in one part of body and regulates the activity of other parts is called as hormones. Plant hormones are produced in the stem, bud and root tips and control the plant growth, formation of flowers, stems, leaves, development, and ripening of fruit, etc. Auxins are specialized hormones which acts on the tip.
Apical dominance means
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Suppression of growth of apical bud by axillary buds
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Suppression of growth of axillary buds by the presence of apical buds
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Stimulation of growth of axillary buds by removal of apical buds
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Inhibition of growth of axillary buds by removal of apical buds
Auxins are generally produced by the growing apices of the stems and roots, from where they migrate to the regions of their action. In most higher plants, the growing apical bud inhibits the growth of the lateral (axillary) buds, a phenomenon called as apical dominance.
Vernalization can remove Kernel wrinkles in:
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Wheat
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Petkus rye
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Maize
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Rice
- Vernalisation is defined as the qualitative or quantitative dependence of plants on exposure to a low temperature to flower. Temperature affects flowering, metabolic activities, and germination of seeds in plants. Plants that grow in mild weather germinate at low temperatures whereas those that grow in hot regions germinate at high temperatures.
- Some plants need exposure to a low temperature to germinate. Furthermore, a plant can be induced to flower in a growing season by exposing it to low temperature. Therefore, it shortens the vegetative phase and hastens flowering in plants.
Vernalization is subjected to plants growing in
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Tropical areas
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Sub tropical
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Temperate areas
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Hot areas/Arctic region
Which of the following is not true regarding vernalisation
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Its a temperature dependent phenomenon
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Its a light dependent phenomenon
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It prevents precocious reproductive development
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Its an aerobic process
The process of induction of flowering in plants, by exposing seeds at low temperature for prolonged periods is called Vernalisation. It is an aerobic, temperature dependent phenomena, prevents precocious reproductive development. It does not depend on light.
So, the correct answer to the question is ‘vernalisation is not a light dependent phenomena’.