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1、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 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
2、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 有了通道细胞 （passage cell）,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：
3、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 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 A
4、ctivity 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,phelloderm,Cork cambium,cortex,endodermis,Broken cortex,Cork cell,Cork 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,S
5、econdary phloem,Vascular cambium 维管形成层,After secondary growth,Secondary structure of root 根的次生结构 Primary xylem is greatly dilated by presence of xylem parenchyma. Wide rays of parenchyma divide xylem into sectors. Rays continue through cambium.,蓖麻 (Ricinus communis),Secondary growth similar to stems
6、. Greater xylem parenchyma than stems. Wider vessels than in stems.,椴树 Tilia americana， eight-year-old root,After the secondary growth, components of secondary structure of root 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 ？ P
7、rimary 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,Pith ray （髓射线）,射线-横向运输,Cross-sectional view of an orchid (Dendrobium 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 structure,More secondary phl
8、oem than secondary xylem in carrot Parenchyma 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 = vascular cambium, 3 = parenchymatous “wood （薄壁细胞的木材）,Storage root of a sugar beet (Beta vulgaris)， showing the
9、 teriary structure 甜菜的储藏根示三生构造,Secondary structure,teriary 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,4) Lateral root 侧根的形成,Lateral root Primordia 侧根原基,Origin: Pericyclen cells (中柱鞘细胞）它的起源方式为 endogenous origin（内起源）。,Format
10、ion of lateral root,Numbers of primary xylem are different in different plants,1.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,Methods of researching on the roots,5) Root 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
11、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,Vigna unguiculata 豇豆的根瘤,根瘤细菌,Function of root nodule: increasing absorbility of plant (uptake of minerals). 根瘤的作用，增加植物的吸收(矿质吸收),Structure of root no
12、dule 根瘤的结构,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。 存在二种菌根: ectomycorrhiza 外生菌根 endom
13、ycorriza 内生菌根,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 . (禾本科),A model of two types of mycorrhizae,（1）Ectomycorrhizae（外生菌根）envelop root tips to establish a symbiotic relationship, forming a
14、 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 ,较松散的.,An ectomycorrhizal association formed in the thin lateral root of alder (桤木）. Hyphae (菌丝) of a mycobiont Basidiomycete (Alpova diplophloeus)
15、共生担子菌, Form a thick compact mantle around the root and penetrate only between the radial walls of the rhizodermis,1 = rhizodermis, 2 = root cap, 3 = apical meristem, 4 = vascular cylinder,Transverse section of an ectomycorrhizal root. 具有外生菌丝根的横切面,Endomycorrhizae penetrate into many of the root cells
16、 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 with large normal nuclear.,The ability of bareley roots to absorb phosphorus With 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 M
