Class (25) = Cytokinin | Introduction, Function & Application |Types of Plant Hormone (Part 02) скачать в хорошем качестве

Class (25) = Cytokinin | Introduction, Function & Application |Types of Plant Hormone (Part 02)

Download "Solution Pharmacy" Mobile App to Get All Uploaded Notes, Model Question Papers, Answer Papers, Online Test and other GPAT Materials - https://play.google.com/store/apps/de... PLANT HORMONES Plant hormones, also known as phytohormones, are chemicals that regulate plant cell processes. They are signal molecules produced within the plant functioning in extremely low concentrations Five major types of plant hormones 1. Auxin 2. Gibberellin 3. Cytokinin 4. Ethylene 5. Abscisic acid Plant growth regulators usually are defined as organic compounds, other than nutrients, that in small concentrations, affect the physiological processes of plants”. If the compound is produced within the plant it is called a plant hormone. The term "hormone" is derived from a Greek word meaning “to arouse or stimulate or enhance an activity. 1. Auxins Auxin is the first plant hormone/growth substance discovered. The term comes from the Greek word, auxein means "to grow". Compounds are generally considered as auxins if they are synthesized by the plant and have similar activity to Indole-3- acetic acid (IAA). The following are some of the responses that auxin is known to cause 1. Stimulates cell loosening, expansion and elongation. 2. Initiation of adventitious roots on stem cuttings 3. Lateral root development in tissue culture 4. Stimulates differentiation of phloem and xylem 5. Stimulation of abscission (young fruits) or delay of abscission 6. Stimulates cell division in tissue culture in combination with cytokinins 7. Mediates the tropistic response of bending in response to gravity and light 2. Gibberellins Physiological processes stimulated by active gibberellins depend on their types. Stimulate cell elongation in stem Breaks seed dormancy in some plants which requires light for germination Stimulates alpha-amylase production in germinating cereal grains Stimulates bolting/flowering in response to long days Delay senescence in leaves and also in citrus fruits Induces maleness in dioecious flowers Play a role in development of seedless fruit (parthenocarpic). 3. Cytokinins In Cytokinin, cyto = cell + kinin = division, i.e. meaning is cell division. Cytokinin is also called as cytokine. These are the compounds resembling with adenine (aminopurine) which stimulates cell division. Functions of Cytokinins Physiological processes stimulated by cytokinins, Stimulates cell division Activates metabolite attraction (sink effect) Retardation of senescence (at low concentrations) Induction of apoptosis (at high concentrations) Stimulates morphogenesis in tissue culture Stimulates the growth of lateral buds and leaf expansion by cell division & enlargement Stimulation of chlorophyll synthesis that causes the conversion of etioplasts into chloroplasts Enhance stomatal opening in some plants 4. Ethylene Ethylene has simplest structure among all the plant hormones. It is a gaseous compound that has effects like an abscisic acid. Flower opening , stimulates fruit ripening 5. Abscisic Acid Abscisic acid (ABA) controls several physiological processes in plants and best known for regulatory role in abiotic stresses like drought and high salinity. It promotes stomatal closing by which plants enable to adapt to water stress (desiccation tolerance). It also controls seed germination, vegetative growth and bud dormancy Get in touch with the solution by just clicking following links- Facebook Group-   / solutionpharamcy   Facebook Page-   / pharmavideo   New channel (Pharmacy Dictionary) -    / @pharmacydictionary   Instagram-   / solutionpharmacy   E-Mail for official and other work - [email protected] LinkedIn-   / pushpendrakpatel   #solutionpharmacy #Pharmacologyclass #GPATonlinetest