植物生理學及植物激素

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(1)植物生理學 (Plant Physiology) 李澤民海洋生物研究所. Introduction 生理 (Physiology) 生命運作的則理植物 (Plant) 具細胞壁可行光合作用可行自營生活的生命型態. 1.

(2) 細胞壁 (Cell wall) 纖維素’(Cellulose). 2.

(3) Tissue 薄壁組織 (Parenchyma) 厚角組織 (Collenchyma) 厚壁組織 (Sclerenchyma). 韌皮部篩管. 木質部導管. 3.

(4) 葉綠體 (chloroplast) 植物細胞之光合作用場所. 4.

(5) Plastid. 葉綠體發育. 5.

(6) 細胞膜 (plasma membrane). Transport and translocation of water and solutes 水為植物生長發育及生產力主要限制因子. 6.

(7) 水為溶質運動的介質 (Fick’s law). 水勢水具有自由能 (chemical potential) 非僅以濃度表示 (not only concentrations). 7.

(8) 植物水份吸收 The water in soil - capillary water - gravitational water Water uptake by roots - 根部的水勢值比周圍土壤的水勢值還低. The path of water in the plant apoplastic transport (細胞間隙) - Casparian bands - transcellularly aquaporin symplastically transport (細胞質). 8.

(9) long-distance transport xylem. 9.

(10) root pressure 水勢差異為水輸送的動力. 10.

(11) 11.

(12) 植物水分散失與平衡蒸散作用 (Transpiration). 12.

(13) 氣孔與保衛細胞. 外界空氣流動影響蒸散作用. 13.

(14) 陸生植物根據對短期水份供應波動及蒸發速率的補償能可分為2大類 Poikilohydric Plants Homoiohydric Plants. Poikilohydric plants 本身的水份含量隨環境溼度(humidity)而變化原核生物,真菌,藻類,地衣,蘚苔,蕨都有這類物種缺乏中央液泡的小細胞乾燥脫水時,細胞均勻皺縮,原生質(protoplasm)內細小構造不受破壞,仍保有生命力水份含量低時, 代謝功能受到抑制,當水份充足時, 恢愎正常代謝作用活動所需的mineral water potential是speciesspecific,並決定物種的分佈某些被子植物物種(homoiohydric plants)的花粉粒和種子內的胚呈現poikilohydric的時期. 14.

(15) Homoiohydric plants 在細胞貯存水份的範圍內,細胞水份含量維持穩定綠藻以上的類群~陸生維管束植物因為有大的液泡,細胞不能忍耐乾旱,原始的 homoiohydric plants只能生長在潮溼的地區保持水份的適應機制角質層→減少水份蒸發氣孔→調節蒸散根系廣大. 不同植物型式的水分關係植物的water balance可根據植物在棲地裡的功能性反應模式,分成2類: 1. Hydrostable plants - 能夠維持適當的water balance, osmotic potential 和leaf water potential 的日,季節性變化範圍窄小 - 氣孔對缺水較敏感;根系廣泛而有效率; 儲存水份(貯存器官,莖或樹幹的樹皮,木材) - aquatic species, succulents, sciophytes, certain grasses and trees of humid region. 15.

(16) 2. Hydrolabile plants - 能承受大量的水份散失,cell sap濃度升高,water potential波動,暫時枯萎,而且可以恢復 - many herbs of sunny habitats, steppe grasses, woody plants (particularly pioneer species), poikilohydric vascular plant, mosses, lichens. 水分平衡的功能性型式 ecophysiological different types (植物對棲地主要環境狀態的反應) 1. Trees 2. Sclerophyllous trees and shrubs 3. Dwarf shrubs and cousion plants of template and cool-humid regions 4. Herbaceous mesophytes and hydrophytes 5. Grasses and sedges 6. Desert plants 7. Hemiparasites 8. Epiphytic vascular plants. 16.

(17) Mineral nutrient Nutrient 營養鹽利用無機營養鹽Æ有機化合物. 17.

(18) 植物所需的營養鹽種類與生理功能. 土壤或溶液介質是植物的營養來源 Mineral Nutrients in the Soil - dissolved in soil water (少部份,<2%) - bound form (多,約98%) →nutrient reserve. 18.

(19) 土壤中的離子吸收和交換黏土礦物及腐植質膠體帶負電,可以吸引並吸附陽離子,土壤中也有部份帶正電的區域, 有陰離子聚集決定陽離子被吸附的強的因子: 1.陽離子所帶的電荷-電荷多,吸附強 2.水合(hydration)的程度-程度低,吸附強養份離子被吸附的好處: 1.減少離子的流失 2.土壤溶液的濃度維持在低且穩定的範圍, 這樣,植物的根和土壤生物不會處在極端的滲透狀況 3.植物容易獲取這些被吸附的離子. 19.

(20) 植物細胞膜對離子的選擇性. 植物細胞膜離子的輸送蛋白. 20.

(21) 植物體內長距離的礦物元素運輸運輸管道 Xylem Phloem phloem transport的主要功能在於重新分配植物體的礦物元素. 21.

(22) Liebig’s “Law of the Minimum 任何1種礦物元的供應量不足都會限制植物的生長植物要達到平衡的代謝,高生產速率,發育順利,必需滿足2項條件 1. 能夠吸收量的macronutrients及trace elements 2. 所有元素的吸收應比例平衡. 植物的礦物元素營狀態 mineral deficiency - 組織中養份的濃度(而非總量)對代謝反應的進行很重要 - 礦物元素貧瘠的棲地,生長成體型矮小的個體是種養份缺乏逆境的應變策略,可濃縮組織中的礦物養份 → accumulation effect - symptom of deficiency adequate mineral supply excessive concentration. 22.

(23) Photosynthesis photochemical processes (light reaction) enzymatic processes (dark reaction) processes of diffusion: O2,CO2在葉綠體和空氣間交換光化學過程: 能量儲存光合作用進行的基本需求: 葉綠素吸收輻射能輻射能接受器:葉綠素(chlorophyll), accessory plastid pigments (carotene胡蘿蔔素, xanthophylls 葉黃素) 所有光合作用生物均具有葉綠素a (chlorophyll a). Absorption spectrum. 23.

(24) Light reaction 2 pigment system: photosystemⅡ(PSⅡ) and photosystemⅠ(PSⅠ) - light harvesting pigment-protein complex(LHPC); antenna pigment; reaction center(chlorophyll-aprotein complex, PSⅡ:P680; PSⅠ:P700) - xanthophylls在移去過多的能量方面,扮擯了重要的角色 (xanthophylls cycle) non-cyclic electron transport: NADP+還原成 NADPH,產生ATP,O2 cyclic electron transport: 產生ATP absorbed radiation energy - fluorescent and phosphorescent light and heat. 24.

(25) Electron transport. 25.

(26) Chloroplast. Components of e- transport. 26.

(27) Redox mechanism. PSI. 27.

(28) PSII. Generation of ATP. 28.

(29) Dark reaction. 29.

(30) C2 cycle: photorespiration. Respiration. 30.

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(32) Mitochondrial e transport. Oxidative Stress. ROS. 32.

(33) ROS generation in both mitochondrial and chloroplast electron-transport chain mitochondrial. NADPH oxidase cell membrane O2 Æ[O2- Æ H2O2] Æ into cellular space (signal). DPI NADPH oxidase inhibitor. (Neill et al. 2002). 33.

(34) Antioxidant Defense ¾ Enzymatic defense mechanism. -SOD, CAT, POX, APOX, GR, GPX ¾ NonNon-enzymatic defense mechanism. -Antioxidants # waterwater-soluble compounds -ascorbate (AsA) -glutathione (GSH) # waterwater-insoluble compounds -α-tocopherol -carotenoids. Main cellular pathway for ROS removal in plant (a) The water-water cycle (b) The ascorbate-glutathione cycle (c) The glutathione peroxidase cycle (d) Catalase. 34.

(35) A hypothetical of the signaling pathway activated in plants in response to external application of oxidants.. secondary metabolite and defense. 35.

(36) Plant growth and development phytochrome. 36.

(37) Blue light. 37.

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(39) Plant hormone Auxin Gibberellin Cytokinin Ethylene Abscisic acid. Auxin. 39.

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(41) Acid growth theory. Gibberellin. 41.

(42) Germination aleurone layer endosperm. 42.

(43) Cytokinin. 43.

(44) Ethylene C2H4. 44.

(45) Abscisic acid. 45.

(46) Stomotal opening. 46.

(47) Salinity Stress Osmotic potential regulation Water flux Ion flux K+, Na+, Cl-. Organic solute accumulation. proline. Proline. Imino Acid Accumulation under Stress Conditions - Compatible Organic Solute: Osmotic Potential - Protection: Bipolar Molecule - Nitrogen and Carbon Resource - Energy: Degradation in Mitochondria - Regulation of Gene Expression. 47.

(48) Thank You!. 48.

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