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Which plant hormone is responsible for cell division and is often used in tissue culture to stimulate shoot formation?
Auxin
Gibberellin
Cytokinin
Abscisic Acid
Cytokinin
Cytokinins are a class of plant growth substances (phytohormones) that promote cell division, or cytokinesis, in plant roots and shoots. In tissue culture, they are specifically utilized in a controlled ratio with auxins to induce the differentiation of shoot buds from undifferentiated callus tissue.
Cytokinins are a class of plant growth substances (phytohormones) that promote cell division, or cytokinesis, in plant roots and shoots. In tissue culture, they are specifically utilized in a controlled ratio with auxins to induce the differentiation of shoot buds from undifferentiated callus tissue.
Think of Cytokinins as the 'factory managers' that tell cells to split and multiply, while Auxins act like the 'designers' that decide the shape and direction of growth.
CYTO-kinin causes CYTO-kinesis (Cell division).
Shoot┬аInitiationтИЭAuxinCytokininтАЛ
Cytokinins act by regulating the cell cycle, specifically promoting the transition from G2тАЛ phase to mitosis. They function by binding to specific receptor proteins (histidine kinases), which initiate a signal transduction cascade resulting in the transcription of genes necessary for cell division. In tissue culture, the ratio of cytokinin to auxin determines organogenesis: high cytokinin-to-auxin ratio promotes shoot development, while a low ratio promotes root development.
Cytokinins are derivatives of the nitrogenous base adenine.
They delay senescence (aging) in leaves by maintaining protein synthesis.
Zeatin is a naturally occurring cytokinin first isolated from maize.
They help overcome apical dominance promoted by auxins.
Used for rapid clonal propagation of plants.
Essential for generating transgenic plants in biotechnology.
Excessive application can lead to abnormal stunted growth or excessive lateral branching.
Plant tissue culture and micropropagation.
Extension of shelf life for cut flowers and vegetables.
Auxin is primarily responsible for cell elongation and apical dominance.
Gibberellin is known for stem elongation and seed germination.
Abscisic acid is the primary growth inhibitor and induces stomatal closure during stress.
C is correct тАФ Cytokinins are the primary plant hormones that promote cell division and are vital for shoot organogenesis in tissue culture.
Always remember the 'Auxin-Cytokinin Ratio' in tissue culture: High Auxin/Low Cytokinin = Roots; High Cytokinin/Low Auxin = Shoots.