Cross-section of tobacco stem (Nicotiana sp.) shows a continuous cylinder. 烟草茎横切
31
3）Vascular cylinder 维管柱
Primary phloem 初生韧皮部
interfascicular cambium 束间形成层
25
么么么么方面
• Sds绝对是假的
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）
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Primary structure of stems in Dicots 双子叶植物茎的初生结构
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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。
Primary xylem （endarch) 初生木质部 (内始式）
Primary phloem fibers 初生韧皮纤维
Fascicular cambium 束中形成层
Pith ray 髓射线
Pith 髓
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Primary structure Of stem in herba Dicot --- alfalfa 草本双子叶植物--紫花苜蓿茎初生 结构
3
Outer characters on the
stem of Carya sp.（胡桃）
腋芽 皮孔 芽鳞痕
4
Stem morphology of a gymnosperm 裸子植物茎外形
叶座 芽鳞痕 （年痕）
Annual growth
Stem of a gymnosperm, fir (Abies sp.) 冷杉, showing circular scars that mark the sites of leaf attachment (叶座）.
anticlinal （垂周）that occur in the tunica (T, 原
套). The initials of the tunica
divide anticlinally only, while
the initials of the corpus also
shows cortex 苜蓿茎示皮层 29
皮层中的绿色组织
30
Primary structure of stems in Dicots 双子叶植物茎的初生结构
3）Vascular cylinder 维管柱
间断的维管束环 连续的环
Cross-section of sunflower stem
shows a collateral bundles ring . 向日葵茎横切
divide periclinally（平周）.
This specimen appears to have 注意：原套（T)细胞壁方向，以后
three cell layers of tunica
发育成表皮、皮层
(identify them).
原体（C)细胞壁方向，以后发育
成皮层、维管束、髓、射线 17
叶痕 Leaf scar
Node 节
Internode 节间
维管束痕 （叶迹）
芽鳞痕 （年痕）
芽鳞痕 （年痕）
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.
原表皮层 叶迹
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叶隙
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
Bud morphology
und鳞er芽SE\M裸芽
扫描电镜下的芽外型
叶芽\花芽\混合芽
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3. Branching of stems 茎的分枝 Monopodial branching 单轴分枝
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2. Branching of stems 茎的分枝
Sympodium branching 合轴分枝
1） Epidermis 表皮
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
The stem of avens (Geum canadense 水杨梅）in a primary state of growth. 28
9
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。
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2. Different types of buds 芽的不同类型
定芽(顶芽\恻芽(腋芽); 不定芽
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
2
(一) 茎的形态 Mophology of stem
1. Outer Morphology of Stem 茎的外部形态
Morphology of an angiosperm stem 被子植物茎外形
顶芽 Terminal bud
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
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葫芦科的攀缘茎---卷须
竹节蓼的叶状茎
一种龙舌兰的丛生叶长在伸长的茎上
Modified stems(变态茎）
adapt plants to different
factors in the
environment.
8
变态茎---草莓的匍匐茎 变态茎---爬山虎的茎吸盘
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
中央母细胞
周围分生组织
髓分生组织 （肋状分生组织）
髓分生组织 （肋状分生组织） 18
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
33
Cucurbita sp. (squash) cross-section of stem
南瓜茎横切面 --- 双韧维 管束
showing the external and internal primary phloem, no vascular cambium is initiated between primary xylem and internal phloem which is left in its primary state.
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.
Chapter Four Structures and development of Plant Organs 植物的器官的结构与生长发育
1
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.
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
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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
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