浙江大学2012植物学甲课件 第04次课2008ppt第01到50页.ppt

Chapter FourStructures and development of Plant Organs 植物的器官的结构与生长发育Section 3 Morphology, structure and development of stems第三节 茎的形态、结构及生长发育 Stems are a important link between leave and roots. Stems are composed of the four kinds of tissues found in all organs of a plant: epidermis, vascular, ground, and meristematic tissues.茎连接根和叶，茎由四种组织 构成：表皮、维管组织、基本 组织和分生组织1. Outer Morphology of Stem 茎的外部形态 The stem tip on the left shows the terminal bud (TB), leaf scars (LS), vascular bundle scars (VB) within the leaf scars, and annular scars (AS) . The right-hand picture shows an ash stem at lower magnification with two annual rings as indicated by arrows.Morphology of an angiosperm stem 被子植物茎外形顶芽 Terminal bud叶痕 Leaf scar芽鳞痕 （年痕）维管束痕 （叶迹）Node 节芽鳞痕 （年痕）Internode节间(一) 茎的形态 Mophology of stemOuter characters on the stem of Carya sp.（胡桃）腋芽皮孔芽鳞痕Stem of a gymnosperm, fir (Abies sp.) 冷杉, showing circular scars that mark the sites of leaf attachment (叶座）.Annual growth from buds is represented by the shorted secondary branches.Stem morphology of a gymnosperm 裸子植物茎外形芽鳞痕 （年痕）Annual growth叶座Different habits of stem 茎的不同习性 Echeveria, 石莲花的茎很短香蕉的茎是由一系列互相重叠的叶柄 组成的Different habits of stem 茎的不同习性Stems play key roles in the ecology of plants竹节蓼的叶状茎一种龙舌兰的丛生叶长在伸长的茎上 葫芦科的攀缘茎---卷须Modified stems(变态 茎）adapt plants to different factors in the environment.变态茎---草莓的匍匐茎变态茎---爬山虎的茎吸盘洋葱的鳞茎---变态地下茎马铃薯的块茎---变态地下茎Modified belowground stems often help plants survive cold winter. 变态的地下茎使植物度过寒冷的冬季。

2. Different types of buds 芽的不同类型Bud morphology under SEM 扫描电镜下的芽外型定芽(顶芽\恻芽(腋芽); 不定芽鳞芽\裸芽叶芽\花芽\混合芽3. Branching of stems 茎的分枝Monopodial branching单轴分枝2. Branching of stems 茎的分枝Sympodium branching合轴分枝False dichotomous branching 假二叉分枝Dichotomous branching 二叉分枝, 见于蕨类植物，是一种 较原始的分枝方式3.Long shoots and short shoots 长枝与短枝Long shoot and short shoot of Ginkgo biloba 银杏的长短枝1. 种子; 2. 分蘖节; 3.不定根Tiller of grass ( Poaceae) 禾本科植物的分蘖1.茎尖结构与发育生长锥 （顶端 分生组织）腋芽 原基叶原基叶迹原形成层基本分生组织叶隙腋芽 原基Morphology of shoot apex 茎尖形态学(二) 茎的结构及其生长发育原表皮层The tunica-corpus organization of the apical meristem. 茎尖分生组织的原套---原体结构Note the cell wall orientations in the corpus (C 原体) as opposed to the strictly anticlinal （垂周） wall orientations that occur in the tunica (T, 原套). The initials of the tunica divide anticlinally only, while the initials of the corpus also divide periclinally（平周）. This specimen appears to have three cell layers of tunica (identify them).注意：原套（T)细胞壁方向，以后 发育成表皮、皮层 原体（C)细胞壁方向，以后发育 成皮层、维管束、髓、射线The tunica-corpus and tissues theory of the apical meristem. 茎尖分生组织的原套---原体及组织学说髓分生组织 （肋状分生组织）周围分生组织髓分生组织 （肋状分生组织）中央母细胞茎尖顶端组织分区 A.一般分区； B.特殊分区 1.原套原始细胞; 2.原体原始细胞; 3.周围分生组织区; 4.肋状分生组织区; 5.形成层状过渡区 The tunica-corpus and tissue theory of the apical meristem. 茎尖分生组织的原套---原体及组织学说• 整个周围区（3）分化形成原表皮、基本分生组织和原形 成层，最后形成表皮、皮层、髓射线和维管束。

• 肋状分生组织（4）细胞经分裂、生长和分化形成髓注意：2- 原体原始细胞产生2部分，外围加入周围区，内侧加入肋状组织2. Zones and development of Shoot apex 茎尖分区与发育Meristematic zoneElongation zoneMaturation zone无根冠结构，但有幼叶包被； 有侧生器官：叶原基和腋芽原基（外起源）Differentiation of the first tracheary element in procambium 在原形成层中第一层导管分子的分化A longitudinal section of lilac (Syringa sp.丁香) behind the shoot apex showing an early stage in the differentiation of vascular tissues in procambium. Note the first annular tracheary element of the protoxylem. 3. Growth of stem 茎的生长 ①顶端生长(apical growth) 来源顶端分生组织。

②居间生长(intercalary growth), 来源居间分生组织禾本科植物）③增粗生长（thickening growth）来源次生分生组织单子叶植物的初 生增粗生长， 是由生长锥叶原 基基部的初生增 粗分生组织活动 而引起的Cross section(横切面） of stem of Corn (玉米). Notice the distribution of vascularbundles(维管束）Stem of Sunflower4. Primary structure of stems茎的初生结构Monocotyledon DicotyledonPrimary structure of stems in Dicots双子叶植物茎的初生结构Stem structure of a herbaceous Plant 草本植物一枝黄花 Medicago sp.Sambucus canadensis 接骨木Rununculus sp. 毛茛Primary structure of stems in Dicots 双子叶植物茎的初生结构Stem structure of a woody plant 木本植物 （Tilia, 椴树） Primary structure of stems in Dicots 双子叶植物茎的初生结构1） Epidermis 表皮The stem of avens (Geum canadense 水杨梅）in a primary state of growth.Characters: 排列紧密，外壁具栓质、角质、蜡被或表皮毛等. Origin: 原表皮The stem of Clover 苜蓿茎表皮Primary structure of stems in Dicots 双子叶植物茎的初生结构 2） Cortex 皮层莲子草茎The stem of Clover shows cortex 苜蓿茎示皮层The stem of shows cortex 莲子草示皮层Characters: 细胞排列疏松，外围几层具叶绿体，后期会加厚。

Origin: 基本分生组织皮层中的绿色组织Primary structure of stems in Dicots 双子叶植物茎的初生结构3）Vascular cylinder 维管柱Cross-section of tobacco stem (Nicotiana sp.) shows a continuous cylinder. 烟草茎横切Cross-section of sunflower stem shows a collateral bundles ring . 向日葵茎横切间断的维管束环连续的环3）Vascular cylinder 维管柱Primary phloem fibers 初生韧皮纤维Primary phloem 初生韧皮部Fascicular cambium 束中形成层Pith ray 髓射线 interfascicular cambium 束间形成层Primary xylem （endarch) 初生木质部 (内始式）Pith 髓 Primary structure Of stem in herba Dicot --- alfalfa草本双子叶植物--- 紫花苜蓿茎初生 结构Cucurbita sp. (squash) cross-section of stem 南瓜茎横切面 --- 双韧维 管束showing the exte。