18 Questions
What is the role of ABA in seeds?
Confering desiccation tolerance and inducing dormancy
What is the outcome of loss of function of ABA signaling in seeds?
Precocious germination
What is the term for the germination of seeds while still attached to the parent plant?
Vivipary
Which of the following proteins are involved in ABA signaling and essential for seed development and dormancy?
SRK2D/SnRK2.2, SRK2E/SnRK2.6/OST1 and SRK2I/SnRK2.3
What is the function of ABA in stomatal aperture regulation?
Regulating stomatal aperture
Which of the following is an example of a plant that lacks seed dormancy?
Rhizophora (red mangrove)
Which hormone is involved in the regulation of elongation in the shoot and root of a germinating soybean?
Gibberellin
What is the function of the TIR1 protein in plant hormone signaling pathways?
Receptor for Auxin
What is the effect of disrupting hormone synthesis or response on plant growth?
Reduced elongation and branching
Which of the following hormones is known to act as 'molecular glue' in plant growth and development?
Hormones in general
What is the role of Brassinosteroids in plant growth and development?
Stimulation of cell growth and elongation
What is the effect of Gibberellin biosynthesis mutants on plant growth?
Reduced stem length
What is required for seed germination to occur?
Elimination of ABA and production of GA
Which hormones regulate fruit growth, maturation, and ripening?
GA, ethylene, and auxin
What is the role of ABA in plant responses to stress?
It helps plants respond to stress
What is the outcome of GA and ethylene promoting flowering in some plants?
Increased seed production
What is true about ABA biosynthesis?
It is strongly regulated
Why is understanding hormonal regulation of reproductive development important for food production?
Because most of our caloric intake is derived from seeds
Study Notes
Abscisic Acid (ABA) Functions
- ABA accumulates in maturing seeds and is essential for seed dormancy and desiccation tolerance.
- ABA synthesis and signaling are required for seed maturation, and its loss of function leads to precocious germination.
- ABA regulates stomatal aperture and is involved in embryonic patterning and reserve accumulation.
ABA Signaling Pathway
- ABA protein kinase and transcription factors are essential for ABA-induced dormancy.
- Three Arabidopsis SnRK2 protein kinases (SRK2D/SnRK2.2, SRK2E/SnRK2.6/OST1, and SRK2I/SnRK2.3) are involved in ABA signaling and are essential for seed development and dormancy.
Hormone Regulation of Plant Growth and Development
- Hormones can act like "molecular glue" to facilitate interactions between proteins.
- Ion channel regulation involves hormone binding, which initiates an information relay.
- Hormones affect vegetative growth, including elongation, branching, and organogenesis.
- GA, Auxin, and Brassinosteroids are involved in regulating plant growth and development.
Hormone Regulation of Reproductive Development
- GA and ethylene promote flowering in some plants.
- Fruit growth, maturation, and ripening are regulated by auxin, GA, and ethylene.
- Seed maturation and germination are regulated by ABA and GA.
Hormonal Responses to Abiotic Stress
- ABA and ethylene help plants respond to stress, including photooxidative stress, high temperature stress, water deficit, drought, soil salinity, air pollution, wounding, and mechanical damage, and cold and freezing stress.
- ABA biosynthesis is strongly regulated, and its levels are tightly controlled to ensure rapid and precise control.
Learn about the role of hormones such as GA, ABA, auxin, and ethylene in plant reproductive development, including seed germination, fruit growth, and flowering. Understand how these hormones regulate plant growth and development.
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