Lecture Plant physiology continue

PLANT PHYSIOLOGY Faculty of Biology Hanoi University of Sciences – VNU 2014 Natural Auxins IAA 4-Cl-IAA Synthetic Auxins IBA dicamba NAA 2,4-D picloram 2,4,5-T Auxin synthesis pathways free conjugated Forms Auxin affects both cell division and enlongation A B C Phototropism Gravitropism Thigmotropism is growth in response to touch Rapid leaf movements in response to mechanical stimulation are examples of transmission of electrical impulses called action potentials Apical dominance Classification depends on origin Ethylen induced leaf abscission WT 50ppm Ethylen in days Other effects of ethylen Ethylen treatment Includes sexual expression Abscisic Acid (ABA) C15H20O4 Similar to part of carotenoid Biosynthesis and transport of ABA in cell G: glucose ester PA: phaseic acid DPA: dihydrophaseic acid 8'-HO ABA: 8'-hydroxy ABA Promotes stomatal closing ABA signaling mechanism Brassinosteroid In 1970, American researchers isolated a bioactivator from mustard plants (Brassica napus L.) and named brassin Brassinosteroid have 5α-cholestane Brassinolide is a well-known brassinosteroid which has 28 carbon atoms in formula Diversity of BR forms Ring A Ring B Chain Biosynthesis Signal transduction pathway BR – growth promotors Bri1 mutants BR and Auxin coordination ... retard aging of some plant organs, perhaps by inhibiting protein breakdown, stimulating RNA and protein synthesis, and mobilizing nutrients May slow leaf deterioration on plants since detached... longer Nutrient Mobilizing Signal transduction pathway What are Gibberellins? •A disease of rice plants called bakanae (foolish seedling) disease was found firstly in Japan This disease was found