Auxins (Indole-3-Acetic Acid, IAA, etc)
Auxin plays a crucial role in regulating growth and development. Indole-3-Acetic Acid (IAA), Indole-3-Butyric Acid (IBA), and 4-chloro-indole-3-acetic acid are all members of this hormone family that are found in nature. Auxin levels vary dramatically within the plant body and throughout the life cycle of the plant, forming complex gradients that appear to be a central component of its regulatory activity for plant development.
Key Functions:
- Promotes cell elongation and division
- Controls apical dominance
- Regulates phototropism and gravitropism
- Influences fruit development
Product ID | Description |
|---|
orb624048 | Plant ABP1 Protein [Zea mays] |
orb1774 | ABP1-Rabbit-Pab [Prunus persica] |
orb604531 | Plant IAA17 protein |
Gibberellins (GAs)
Gibberellins are plant hormones that regulate various developmental processes, including stem elongation, germination, flowering, and enzyme induction. There are over 135 known gibberellins, with GA3 (gibberellic acid) being the most extensively studied. While gibberellins have significant effects on above-ground plant parts, they generally have minimal impact on root growth.
Key Functions:
- Stimulates stem elongation
- Promotes seed germination and breaks seed dormancy
- Regulates flower development and fruit set
- Influences leaf expansion and pollen development
Cytokinins (CKs)
Cytokinins are plant hormones that stimulate cell division and play crucial roles in plant growth and development, with zeatin being the most common natural cytokinin. They are primarily produced in root tips and transported to shoots via the xylem, where they promote lateral bud growth, chloroplast development, and leaf senescence. Cytokinins are transported through the xylem and phloem while coordinating root and shoot growth, though the specific mechanisms of their cellular transport are not yet fully understood.
Key Functions:
- Promotes cell division in meristematic tissues
- Delays leaf senescence
- Stimulates chloroplast development
Abscisic Acid (ABA)
Abscisic acid (ABA) is primarily known for its role in stress responses and growth inhibition. Despite its name, ABA does not directly cause abscission but rather inhibits growth and helps plants tolerate abiotic stresses. It is synthesised from xanthophylls in mature leaves, stems, developing fruits, and seeds and is transported throughout the plant via xylem, phloem, and parenchyma cells. ABA plays important roles in various physiological processes, including stomatal closure during water stress, seed dormancy induction, root development under nutrient deprivation, and the regulation of stress-responsive genes.
Key Functions:
- Regulates stomatal closure during water stress
- Promotes seed dormancy and inhibits germination
- Induces leaf senescence and abscission
Ethylene
Ethylene regulates plant growth, development, and stress responses throughout a plant's life cycle. Ethylene is synthesized from S-adenosyl-L-methionine (SAM) through a two-step process involving ACC synthase and ACC oxidase enzymes, and its production is triggered by various environmental stresses.
Key Functions:
- Promotes fruit ripening
- Stimulates leaf and fruit abscission
- Regulates seedling growth and development
Brassinosteroids
Brassinosteroids are plant hormones structurally similar to animal steroid hormones. Brassinosteroids regulate plant development and environmental adaptations, with at least 70 known polyhydroxylated sterols in this class. Their functions include mediating plant responses to abiotic and biotic stresses, regulating flowering time, and influencing fertility, with brassinosteroid deficiency linked to dwarfing phenotypes and reduced fertility in plants.
Key Functions:
- Promotes cell elongation and division
- Enhances vascular differentiation
- Improves plant tolerance to various stresses
Other Memebers
In addition to well-known phytohormones like auxins and gibberellins, other hormones, such as jasmonic acid (JA), strigolactones (SLs), and salicylic acid (SA), also play significant roles in plant growth and development. Jasmonic acid, first isolated in 1957, is crucial for plant defense and stress responses, influencing processes like flowering and senescence.
Strigolactones, derived from carotenoids, are important for regulating plant architecture and promoting symbiosis with fungi, which can enhance root development and resistance to parasitic plants. Salicylic acid, a naturally occurring hormone, affects various physiological processes, including photosynthesis, flowering, and nutrient uptake, while also influencing stress responses and plant nutrition. Overall, these hormones work together to ensure optimal plant growth and resilience in diverse environments.
Phytohormones play pivotal roles throughout a plant's life cycle, from seed germination to senescence. The interplay between phytohormones and root-associated microbes offers a promising frontier in plant science. Their study is crucial for developing innovative approaches to promote robust growth, improve crop yields, and enhance resilience against both biotic and abiotic stressors. Moreover, understanding phytohormone signaling networks can lead to the development of precision agriculture techniques, tailored plant breeding programs, and novel pest management strategies, ultimately contributing to global food security and environmental sustainability.
