高級(jí)植物生理學(xué)課件第七章植物的生殖生理(已修改)
2025-01-28 01:26 本頁(yè)面
【正文】 1 Plant Reproduction Zichao Mao 2 Life cycle of plant 3 ? Transition to reproduction ? Flower an development ? Gametogenesis and fertilization Plant Reproduction 4 Transition to reproduction Vegetative phase Reproductive phase Inflorescence Flower 5 Production of flowers involves two transitions in Arabidopsis SC: stem cell P: an primordia Se: sepal 1. Convert SAM （Shoot Apical Meristem) to inflorescence meristem (infinite, making lateral ans) 2. Convert inflorescence meristem to floral meristem (terminal, flowers) 6 Factors regulating the transitions Vegetative meristem Inflorescence meristem Floral meristem ? Genes (floweringtime genes and floral identity genes) ? Light (photoperiod) ? The biological clock ? Temperature ? Hormones 7 affecting the transition of vegetative growth to reproductive growth WT emf2 Floweringtime genes emf1 embryonic flower 8 affecting formation of inflorescence and floral meristems Floral identity genes Inflorescence (from Inflorescence meristem) Flower (from Floral meristem) 9 terminal flower 1 (tfl1): Convert the inflorescence meristem to the flower meristem. leafy (lfy): produce more inflorescences, delayed flowering Mutations in floral identity genes tfl1 ? [FUNCTION] Controls inflorescence meristem identity and is required for maintenance of a indeterminate inflorescence. Prevents the expression of 39。APETALA139。 and 39。LEAFY39。. Also plays a role in the regulation of the time of flowering in the longday flowering pathway. May form plexes with phosphorylated ligands by interfering with kinases and their effectors] Expressed below the apical dome of inflorescence and coflorescence meristems, and in inflorescence stem. Weakly expressed in vegetative phase from day 2 or day 3. Increased expression after mitment to flowering from day 7 on. LEAFY。 ? LFY, FUNCTIONS IN: chromatin DNA binding, transcription factor activity, sequencespecific DNA binding。 INVOLVED IN: flower development, maintenance of inflorescence meristem identity, response to gibberellin stimulus, gibberellic acid mediated signaling。 LOCATED IN: nucleus。 ? EXPRESSED IN: shoot apex, leaf whorl, embryo, flower, seed。 EXPRESSED DURING: 7 growth stages。 12 Factors regulating the transition to reproduction Vegetative meristem Inflorescence meristem Floral meristem EMF TF1 LFY 13 Garner and Allard (1920’s) The discovery of photoperiodism Soybeans (Glycine max) planted over a threemonth period all flowered about the same time 14 Many more experiments were followed: ? Eliminate a variety of environmental conditions: Nutrition, temperature, and light intensity ? Relative length of day and night decides the flowering time Photoperiodism: ability of an anism to measure the proportion of daylight
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