植物营养学复习要点第一章：Questions-21、How to assess 评价 an element that is essential to higher plants?( 1) A given plant must be unable to complete its life cycle in the absence of the mineral element; ( 2) The function of the element must not be replaceable by another mineral element;( 3) The element must be directly involved in plant metabolism- for example, as a component of an essential plant constituent such as an enzyme- or it must be required for a distinct metabolic step such as an enzyme reaction.2、How many kinds of elements are essential for higher plants? 183、What are the general functions of the essential elements for higher plants?As the constituents成分 of important compounds in plant；As the constituents or activators of enzymes作为酶的成分或激活剂Stabilize the structure of the cell4、Please describe the general composition of a living plant.Water 、 Dry matter ( Organic matter and ashes/ minerals )5、Terms:Hyperaccumulation,phytoremediation,Macronutrients,micronutrients,three essentials of fertilizerMacronutrients ： C,H,O,N,P,K,Ca,Mg,S 。 Micronutrients ： Cu,Zn,Mn,Fe,B,Mo,CI,Ni ， Co。Questions-31、What are the main functions of plant roots? Anchoring 固定 the plant in the soil Absorption and translocation of water and nutrients Synthesis of phytohormones植物激素 and other organic compoundsStorage 存储 of inorganic and organic nutrients2、There are two kinds of roots, what are they? 须根系( fibrous root system )、直根系 (tap root system )3、Whats root hair? Cluster root?群集根root hair ： Root hairs are tubular 管状物的 tensions of the root epidermal 表皮 cell and occur as a result of lateral cell growth.Cluster root ：4、There are many environmental factors that affect root growth. What are they? How they affect the growth of root?Soil compaction ：土壤容重 1.1-1.3 g/cm3 适宜旱地作物生长。 溶液中根系细长，土壤中根系粗短。Soil temperature ：适宜温度： 20-25 Water ：“干长根，湿长苗” Nutrient ：根系具有趋肥性Questions-41、How many parts of a root tip could be divided into?Meristematic zone 分生区、 Elongation zone 伸长区、 Hair zone 根冠。2、Please describe the transverse section 截面 of a young root Root hairs/ 根毛、 Epidermis/ 表皮、 Parenchyma/ 皮层薄壁组织、 Endodermis/ 内皮层、 Stele/ 中柱。3、Whats free space in a root? Donnan free space and water free space?free space ：在根的某些组织或细胞内允许外部溶液通过自由扩散进出的那些区域。 水分自由空间：水溶性离子可自由进出的那部分空间 . 杜南自由空间：细胞组织上所带的负电菏点位而吸持阳离子排斥阳离子所占据的空间 。4、What are apoplast and symplast?Symplast ： the cytoplasmatic continuum formed by numerous plasmodesmata. 共质体：指各个活的细胞通过胞间连丝相互连在一起形成的统一体Apoplast ： comprises all parts of the tissue open to solutes and water without their having to cross a membrane. 质外体：植物组织中细胞壁的连续体，包括细胞壁、细胞间隙和木质部导管等非原生质 的部分。5、Please describe the structure of a cell membrane. 大约等比例的蛋白质和脂质分子组成，约7 to 10 nm 厚。Questions-51、What is active and passive absorption of elements by plant root cells? passive uptake: 顺浓度或电化学梯度、不消耗能量、无选择性。 active uptake ：逆浓度或电化学梯度、消耗能量、有选择性。2、What is ion pumps, ion channels?ion channels ：是细胞膜上具有选择性的孔状跨膜蛋白，可以允许离子迅速透过质膜，能快速开启和关闭。 ion pumps ：3、Why Nernst Equation is useful for interpreting解释 the ion transport into plasma原生质membrane?4、What, generally, is the mechanism that has been proposed to account for the active absorption of ions by roots?载体学说 (Carrier transport) 、离子泵学说 (Ion pump)5、Is the driving force the same for charged nutrients and uncharged nutrients across the membrane? Explain your answer.Uncharged molecules 不带电的 move in response to: differences in concentration(chemical gradient) Charged molecules move in response to:differences in concentration (chemical gradient) 、 differences in voltage(electrical gradient)= electro-chemical gradient6、Please describe the types of transporters existed in the membranes.主动运输、被动扩散、内吞外排。7、Km, Cmin, ImaxImax: maximal net influx of ions into roots离子进入根的最大量Km: Michaelis-Menten constant 米氏常数Cmin: Concentration of nutrient in medium养分介质中的浓度 when influx=efflux 当进出相等Questions-61、What is foliar fertilization?The process of nutrient uptake by leaves and other aerial plant organs(也称为根外营养 ).吸收速度快而且立即参与2、What are the advantages and disadvantages of foliar fertilization? Advantages ： Preventing the fixation or transformation of nutrients or plant growth regulators in soils 防止养分在土壤中固定和转移。High uptake rate and immediately involving plant metabolism代谢。些养分Disadvantages ：补充养分数量有限，不能满足植物对大量元素的需要；效果快，但持续时间短； 难于从叶片向其他部位运输。3、How to increase the uptake efficiency of nutrients applied by foliar spraying?Nutrient species ； Concentration and pH of nutrients ； Wetting time 润湿时间； Leaf type ； Mobility of nutrient in plantQuestions-71、Why the occurrence of calcium deficiency is usually observed in some plants grown in calcareous soil?2、Why the earliest visible deficiency symptoms of N, P and K appear in the older leaves of plants? Ca, Fe, Zn, et. al deficiency symptoms appear in younger leaves?N, P and K 在植物体可移动； Ca, Fe, Zn, 在植物体不可移动。3、Why boron toxicity of plant is usually observed in the margins of older