Tag: plant growth
Questions Related to plant growth
In signoid growth curve, upper asymptote represents period of
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Establishment
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Negative acceleration
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Positive acceleration
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Equilibrium
In a sigmoid growth curve, there are three phases, lag phase, exponential phase and steady state phase. The upper limit of the curve is called as upper asymptote. It represents the period of equilibrium. At this stage, birth rate and death rate are at balance. It is said to be at equilibrium because at this stage, there is equilibrium between biotic potential and environmental resistance.
State whether the following statements are true or false.
Ethylene stimulates leaf release, while auxin keeps leaves from falling.
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True
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False
Ethylene is a gaseous hormone which stimulates the transverse growth but inhibits the longitudinal growth. Auxin delays the abscission of young leaves and provides nutrition to it so that they do not die down while ethylene increases the senescence of leaves and flowers and produces more gas which leads to loss of leaves.
Which of the following is not a feature of a J-shaped growth form of population?
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It is found in stable type of population.
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Exponential phase is very rapid.
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A crash phase occurs at the end of the growth.
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Environmental resistance does not operate.
J-shaped growth curve is a curve on a graph that records the situation in which, in a new environment, the population density of an organism increases rapidly in and exponential or logarithmic form, but then stops abruptly as environmental resistance or some other factor suddenly becomes effective. The actual rate of population change depends on the biotic potential and population size. It may be summarized mathematically as
Because of the which of the following reason/s, growth stops completely during the stationary phase?
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Lack of nutrients
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Saturation of nutrients
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Over availability of nutrients
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None of the above
The stationary phase is the phase in which the growth of lant generally stops and the plant proceeds towards maturity it may occur due to the lack of nutrients majorly seen in the unfavourable season.
Incorrect about geometrical growth
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After mitosis both daughter cells retain the capacity of division
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Growth pattern follows sigmoid curve
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Less common than arithmetic growth in the plants
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Growth rapidly increases
In geometrical growth both the progeny cells following mitotic cell division retain the ability to divide and continue to do so. However, with a limited supply of nutrients, the growth becomes slow which lead to the stationary stage. A sigmoid curve is the characteristic of organism living is the natural environment.
Exponential growth is shown during
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Lag phase
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Log phase
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Maturation phase
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Senescence phase
Choose the correct answer from the alternatives given.
The auxanometer is used for measuring the:
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growth of a fruit
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growth of a cell
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width of the stem
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length of the stem
Dormant seeds are
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Succulent
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Dry
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Wet
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Soft
The non-germinating seeds are called as dormant seeds and contain hard coat which is impermeable to water, gases so restrict water uptake and oxygen exchange.
The cause of dormancy for sometime in fertilized ovule is
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Presence of Auxin hormone
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Zygote divides only after certain amount of endosperm is formed
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Presence of growth inhibitor ABA
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Presence of least amount of water
The fertilized ovule is got dormant so that the adequate amount of endosperm is formed as for division and for further survival, it is very necessary that ample amount of food is present in the seed.
Which of the following breaks the dormancy of potato tubes?
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IAA
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ABA
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Zeatin
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Gibberellin
Dormancy of seeds could be broken by the activation of digestive enzymes like alpha amylases. It is being done by phytohormones like gibberellic acid. It also helps in cell elongation, division of lateral meristem and many more.