植物学课程课件2012

1、 Chapter FourStructures and development of Organs of Plants 植物器官的结构与生长发育器官：由多种组织按一定分布规律构成的，共同担负 同一类生理功能的结构单位。LeavesStemrootsVegetative organs 营养器官第一节：种子的萌发及幼苗的形成（自学）1、种子萌发的条件2、种子萌发的一般过程3、幼苗的类型Section 2 Morphology, structure and development of roots 第二节 根的形态、结构及生长发育 Roots are s plants link to the und

2、erground environment. Taproot systems of Diocots have one large primary root and many smaller branch roots Fibrous root systems of a grassconsist of a mass of similarly sized roots.单子叶植物的须根系双子叶植物的直根系Root system and morphological characters 根系和根的形态特点Embryo rootThe adventitious roots may have similar

3、structures and functions with normal roots (定根）. adventitious roots 不定根Zea mays at the base of a plant cutting天竹葵扦插根 -不定根2. Structure and development of Root 根的结构和生长发育2.1 Structure and elongation development of root tip 根尖的结构与根的伸长生长 The subapical region of the root includes the zones of cell maturat

4、ion (成熟区）,cell elongation (伸长区）, cell division （分生区）, Root cap 根冠顶端分生组织The root cap protects the growing parts of a root as the root grows through the soil 根冠保护根的生长区域在土壤里向前运动。In most dicots, cells of rhizodermis have a common origin with the rootcap cells as shown in Figs. A, B & C). while in most m

5、onocots all cells of the root have indepen -dent origin from the rootcap, as shown in Figs. D, E & F.在大多数双子叶植物中，根表皮细胞与根冠细胞有共同的起源，而在单子叶植物中，所有根冠的细胞都独立地起源于根冠原。根尖原分生组织细胞 分 层Dermatocalyptrogen 表皮根冠原protoderm表皮原（表皮）Rootcap根冠Periblem 皮层原ground meristem (cortex)基本分生组织（皮层）Plerome 中柱原There are three different

6、 tiers of initials in Diocots. 在双子叶植物中有三层不同的原始细胞。Procambium （central cylinder ）原形成层（中柱 ）calyptrogen根冠原Rootcap根冠Dermatogen 表皮与皮层原ground meristem (cortex)基本分生组织（皮层）Epidermis 表皮Plerome 中柱原in Monocots 在单子叶植物中Procambium & central cylinder 前形成层和中柱 Quiescent center 不活动中心A diagram illustrating the location

7、of the root quiescent center (stippled region) in which low mitotic activity occurs.有丝分裂活性很低E = protoderm (to form rhizodermis), 表皮原-根被皮S = limits of the future vascular cylinder将来维管束界限cell elongation 伸长区细胞伸长，液泡化并逐渐分化成熟。 cell maturation （Root hair zone） 成熟区细胞成熟，根毛出现，各种组织形成Root hair zone 根毛区根毛寿命短，与土壤

8、紧密接触，便于吸收水份、养分皮层表皮中拄内皮层外皮层皮层（Ranunculus sp., 一种毛茛) 2.2 The primary structure of root 根的初生结构 Dicots （双子叶植物） A cross section through a mature zone of root tip.A complete transverse section of Ranunculus sp. root at a level showing the completion of primary growth. Note the lack of pith, accumulation o

9、f starch in cortical cells, and the absence of starch in the rhizodermis and exodermis. 毛茛根的初生结构注意无髓，在皮层细胞有淀粉积累，但在表皮和外皮层缺乏淀粉。A. Root epidermis and characters 根的表皮及其特征 垂直B. Root cortex and characters 根的皮层及其特征 The Casparian strip (凯氏带）and Casparian dots（凯氏点） in the endodermis （内皮层） 起到横向运输的主动控制作用。凯氏带Ca

10、sparian dots（凯氏点）内皮层细胞质Cotton root shows Casparian strip（凯氏带） Two endodermis cellsshow the cell wall with phellem. 内皮层细胞壁栓质加厚，不透水、气。C. central cylinder （中柱） the primary xylem （初生木质部）(stained red), as well as the primary phloem (初生韧皮部，stained green) followed a centripetal, exarch order of differentia

11、tion （分化是外始式）. The vascular cambium is located between the xylem and the phloem. (维管形成层位于木韧之间。）a fully differentiated vascular cylinder.Pericycle中柱鞘Endodermis内皮层primary xylem 初生木质部primary phloem 初生韧皮部vascular cambium initiation维管形成层初期 (原形成层)Casparian strip (凯氏带）of the endodermal cells on radial wall

12、 (径向壁）Monocots （单子叶植物） A cross section through a mature monocot root髓内皮层维管组织表皮皮层（Smilax, 菝葜)Pericycle中柱鞘Endodermis内皮层primary xylem 初生木质部primary phloem 初生韧皮部Epidermis表皮Cortex皮层Wheat root 小麦根结构Pericycle中柱鞘Endodermis内皮层primary xylem 初生木质部primary phloem 初生韧皮部Epidermis表皮Cortex外皮层细胞壁加厚Corn root 玉米根结构Pith

13、髓exodermis外皮层细胞壁加厚Details of mature corn root structure. Rhizodermis (根被）is replaced by exodermis （外皮层）. Endodermis （内皮层）walls are lignified & suberized （木化和栓化）单子叶植物内皮层细胞五面加厚，有了通道细胞（passage cell）水分、养分如何进出？ Two schemathe arrangement of the Casparian strip in the endodermis cell walls凯氏带的结构单子叶植物五面加厚有了

14、通道细胞 （passage cell） 2.3 The secondary growth & secondary structure of root in Dicots 双子叶植物根的次生生长与次生结构Forming & development of vascular cambium 维管形成层的发生及其活动Origin 来源：位于初生韧皮部内方薄壁细胞中的原形成层薄壁细胞和正对原生木质部的中柱鞘细胞恢复分生能力连成波状的维管形成层环. Forming process of vascular cambium （1）维管形成层的形成过程（1）Forming process of vascular

15、 cambium （2）维管形成层的形成过程（2）Forming process of vascular cambium （3）维管形成层的形成过程（3）Forming & development of cork cambium 木栓形成层的发生及其活动Origin:部分中柱鞘细胞恢复分生能力，形成木栓形成层Activity 活动：切向分裂，向外产生多层的木栓细胞(cork cell)，组成木栓层，向内产生栓内层(phelloderm)。1.皮层; 2.内皮层; 3.木栓形成层; 4.皮层碎片; 5.木栓层 6. 栓内层phellodermCork cambiumcortexendodermi

16、sBroken cortexCork cellCork cambium，cork cell，and phelloderm compose periderm 由木栓层、木栓形成层和栓内层共同组成周皮Cork cell Cork cambium，Phelloderm Periderm周皮Secondary phloemVascular cambium维管形成层After secondary growthSecondary structure of root 根的次生结构After the secondary growth, components of secondarystructure of r

17、oot in Dicots 双子叶植物根次生生长后的结构组成Periderm 周皮 （什么组织？）Secondary phloem次生韧皮部 ？Vascular cambium 维管形成层 ？Secondary xylem次生木质部 ？Primary xylem初生木质部 ？Pith 髓 ？初生韧皮部 Ray射线A cross section of peach root shows developed secondary structure 梨次生根横切示发达的次生结构Vascular ray （维管射线）射线-横向运输Cross-sectional view of an orchid (De

18、ndrobium sp.) aerial root，showing different endodermis. 兰科一种石斛横切面观示不同的内皮层Special roots structureMore secondary phloem than secondary xylem in carrotParenchyma predominates in vascular tissues.在胡萝卜根，薄壁细胞在维管组织中占主导地位，次生韧皮部比次生木质部更发达the lack of hard mechanical tissues.缺乏较硬的机械组织1 = secondary phloem, 2 = v

19、ascular cambium, 3 = parenchymatous “wood （薄壁细胞的木材）Storage root of a sugar beet (Beta vulgaris)， showing the teriary structure甜菜的储藏根示三生构造Secondary structureteriary structure三生构造Storage root of sweet potato (Ipomoea batatas)地瓜的储藏根With a lot of storage paranchyma cells.具有大量的储藏薄壁细胞2.4 Lateral root 侧根的形

20、成Lateral rootPrimordia侧根原基Origin: Pericyclen cells (中柱鞘细胞）它的起源方式为 endogenous origin（内起源）。Formation of lateral rootNumbers of primary xylem are different in different plants1.原生木质部; 2.后生木质部; 3.初生韧皮部;4.侧根Formation position of lateral roots is relation to numbers of primary xylem侧根形成的位置与初生木质部的数目有关2.5 R

21、oot nudule and mycorrhiza 根瘤与菌根 植物根系与土壤中的微生物有密切的关系，根部分泌的物质，许多是微生物的营养来源，而土壤微生物分泌的一些物质，又可直接或间接影响根的生长发育。 有些微生物甚至可入侵到根的组织中与根发生共生(symbiosis)关系。高等植物根与土壤微生物发生的共生现象，通常有: root nodule and mycorrhiza Glycine max 大豆的根瘤一种松树的外生菌根.Vigna unguiculata豇豆的根瘤根瘤细菌Function of root nodule: increasing absorbility of plant(u

22、ptake of minerals). 根瘤的作用，增加植物的吸收(矿质吸收)Structure of root nodule 根瘤的结构 根 瘤 形 成根 瘤 形 态 mycorrhizae 菌根 The roots of most species of seed plants (at least 80%) have asymbiotic relationship with soil fungi in which both organisms benefit. The association are known as mycorrhizae. 许多高等植物的根(80%)能与土壤中的某些真菌发

23、生共生关系。这些和真菌发生共生的根，称为菌根。 无严格的专一性，比根瘤更普遍。A、外生菌根ectomycorrhiza ： 真菌的菌丝包在根尖的外面，形成鞘状的菌丝体 结构，仅有少数菌丝侵入到皮层的细胞间隙中。B、内生菌根endomycorriza ： 真菌的菌丝侵入到根的表皮和皮层细胞内生长。1 is a representation of ectomycorrhiza in birch (Betula pendula); 在桦树中的外生菌根2 is a representation of endomycorriza in Deschampsia cespitosa. 在发草中的内生菌根 .

24、 (禾本科)A model of two types of mycorrhizae A. Ectomycorrhizae（外生菌根）envelop root tips to establish a symbiotic relationship, forming a thick compact mantle（外套） around the root and penetrate only between the radial walls of the rhizodermis( 根被皮）Ectomycorrhizae of a Pinus sp.一种松树的外生菌根 较松散An ectomycorrhi

25、zal association formed in the thin lateral root of alder (桤木）. Hyphae (菌丝) of a mycobiont Basidiomycete (Alpova diplophloeus) 共生担子菌,Form a thick compact mantle around the root and penetrate only between the radial walls of the rhizodermis1 = rhizodermis, 2 = root cap, 3 = apical meristem, 4 = vascul

26、ar cylinder Transverse section of an ectomycorrhizal root.具有外生菌丝根的横切面B. Endomycorrhizae penetrate into many of the root cells 内生菌根渗透到许多根细胞中.Vesicular-arbuscular endomycorrhizae (囊泡吸器状内生菌根)Exteranal mycelium外部的菌丝体皮层凯氏带囊泡内皮层分枝状吸器表皮3 = 增大的有菌丝的外部皮层细胞 5 = arbuscle 分枝吸器 真菌菌丝The plant cells are healthy wit

27、h large normal nuclear.The ability of bareley roots to absorb phosphorusWith fungi and without fungi in solutions of different concentrations 大麦根在有真菌和无真菌情况下对不同浓度土壤磷吸收的能力.Test on Function of MycorrhizaeIn Citrus sp.菌根的作用，在一种橘属植物中的试验。Function of mycorrhizae: increasing absorbility of plant菌根的作用，增加植物的吸

28、收 Without mycorrhizae with mycorrhizaeHaustorium(Modified root) ofmistletoe. The host is juniper寄生植物-槲寄生的吸根,寄主是柏树柏树木材部位吸根3. The roots of Bryophyta, Fern and Gymnospermae 苔藓、蕨类及裸子植物的根3.1 Structures of rhizoids of bryophyta (苔藓植物的根) No true roots, only have rhizoids Rhizoids 假根Simple rhizoids简单假根Ligul

29、e rhizoids舌状假根Simple rhizoids have the adhesion function (附着功能), and ligule rhizoids have the absorb function (吸收功能).注意: 苔藓植物主要是配子体Rhizoids of liverwort 地钱的假根 Rhizoids of Moss 藓的假根 多细胞假根寄生的孢子体”根”The rhizoids of Bryophyta have additionally a function of vegetative reproduction. 苔藓植物的根还具有营养繁殖作用3.2 Roo

30、ts of fern 蕨类植物的根 蕨类植物是陆生植物中最早分化出维管组织的植物类群，其营养体为孢子体（sporophyte)，有了真正的根、茎、叶等器官分化。所以又叫维管植物. The vascular composed also of xylem and phloem, but only have tracheids (管胞) in xylem and seive cells (筛胞) in phloem.为不定根，二叉分枝或不分枝，有细小侧根。 生长于匍匐茎的下表面（石松类）、 根状茎的节上（木贼类、真蕨类）、 由茎变态形成的根托上（卷柏类）。根生长于匍匐茎的下表面（石松类）根生于孢子体根状茎的节上（木贼类、真蕨类）Structures of roots in fern 瓶儿小草根的横切面示单原型中柱 1.表皮; 2.皮层; 3.中柱生长点纵切面 1. 顶端分生组织细胞; 2.根冠