植物学：第二章 植物组织 tissue-2.ppt

1,筛管sieve tube 伴胞companion cell,筛管 被子植物的韧皮部,运输有机物.,筛管由管状的无细胞核的活细胞连接成 组成筛管的每个细胞叫做筛管分子 sieve elements,2,筛管分子的细胞壁为初生壁性质 端壁称为筛板；分布有小孔-筛孔3,筛板和筛孔,Mature sieve-tube members from the phloem in the stem of corn and squash.,4,5,筛管运送养分的速度10-100cm/h,6,7,受伤时，通过筛孔的原生质形成联络索阻断相邻的筛管分子,筛孔纵切面（侧面观）,8,筛管分子的老化胼胝质沉积在筛板上，形成胼胝体阻断筛孔，失去输导功能9,胼胝体（绿色荧光）,10,P-protein (phloem protein),A protein found in large amounts in the sap-conducting sieve elements of phloem tissue in plants. It takes various forms in the mature sieve element, depending on plant species, ranging from a network of filaments to discrete crystalline bodies. One general property is its ability to form a gel, and it functions as a puncture repair substance, forming a plug at any site of damage in the sieve element, thus preventing loss of food materials being translocated by the phloem. In an intact functioning sieve element, the P-protein is mainly found lining the interior wall.,11,Longitudinal section of sieve tube members in stem of cucumber (Cucumis). This material was fixed in such a way as to enhance the formation of P-protein plugs, two of which are present here, stained red.,12,筛管分子侧壁上存在着初生纹孔场筛域,13,伴胞-筛管旁边的一个或多个小细胞。

The phloem in the stem of squash南瓜,14,sieve tube members can have multiple companion cells,15,筛管分子与伴胞之间具有筛域和胞间连丝,?,?,16,筛管和伴胞由一个细胞不等分裂产生,17,18,19,20,Sieve tube members and companion cells typically function for only a few weeks or months , then are replaced by new cells.,21,Transverse section of phloem in a cactus (Espostoopsis dybowskii). the phloem of this species is trapped between the expanding xylem,22,Transverse section of old stem of grape (Vitis) from a stem that was much older; the sieve tube members and companion cells have collapsed into the solid, dark red mass,23,筛胞 蕨类和裸子植物体内输导有机物的细胞。

Transverse section of a fern rhizome (Pteridium aquilinum). The center of this micrograph is occupied by xylem (the large red-stained cells), and surrounding that is a band of large, empty-looking cells with thin walls (arrows); those are the sieve cells of this fern (蕨类)phloem.,24,筛管 被子植物韧皮部 呈管道状，管径较大 端壁有筛板,有伴胞 输导能力较强,筛胞 蕨类，裸子植物韧皮部 呈细胞状，管径小， 尖削端相接无筛板无伴胞 输导功能较弱,25,（三）机械组织 mechanical tissue,细胞壁均匀或不均匀次生加厚26,机械组织根据形态及细胞壁的加厚方式，可分为 厚角组织 collenchyma 厚壁组织 scleranchyma,27,厚角组织 活细胞 Collenchyma 角隅处增厚,是初生壁性质 初生机械组织 表皮内方。

28,Collenchyma of Anemopsis stem (鱼腥草),29,30,A transverse section of a mature collenchyma cell from the filament of a wheat stamen,31,32,collenchyma of Cucurbita (葫芦) stem,33,厚角组织 细胞是引长的，两端多呈斜形或尖形，彼此重叠连结成束34,功能：支持 又适应器官的生长 普遍存在于尚在伸长或经常摆动的器官中,35,2 厚壁组织死细胞 Sclerenchyma 次生壁secondary wall 次生的机械组织 包括 纤维 石细胞,36,纤维 fiber,起主要支持作用的组织 包括 韧皮纤维 木纤维,37,纤维（横切面）,38,39,40,41,芭蕉科植物蕉麻的韧皮纤维 Harvesting Musa textilis,commonly known as abaca, or Manila hemp.,42,石细胞stone cell,细胞腔狭小，原生质体消失，仅具有坚硬的细胞壁，起支持作用梨果肉的石细胞,43,44,壁出现同心层次，并有分枝状纹孔道,45,梨果肉,椰子内果皮,山茶叶柄,茶叶片,菜豆种皮,桃内果皮,萍篷草属叶柄,46,Branched Sclereids,47,（四）保护组织 protective tissue,分布位置- 主要功能- 根据来源和形态结构分为 表皮初生保护组织（活细胞） 周皮次生保护组织（起作用的是死细胞),48,1）表皮 epidermis 通常是一层细胞组成的，但也有少数植物有几层细胞构成的复表皮,49,Abaxial epidermis of Arabidopsis leaf,表皮细胞行状扁平，排列紧密，无细胞间隙,50,表皮细胞的外壁增厚，形成角质层cuticle,角质层,51,幼嫩表皮上有附属结构,trichomes,Root hairs,52,茅膏菜,53,Stinging hairs of stinging nettle （荨麻）are cells filled with toxin. The tip is pointed and glassy, which makes it brittle and easy broken. The small tip allows it to catch in an animals skin and break off, thus releasing the toxin.,54,荨麻,55,气孔器stoma：保卫细胞 (+副卫细胞)+ 气孔口,As the cuticle is air-tight as well as water-proof it must be perforated to allow for gas exchange.,56,57,Arabidopsis leaf epidermis,58,59,60,（2）周皮：periderm 次生保护组织,61,周皮,木栓层-多层死细胞,保护作用 木栓形成层-1层细胞，分生组织。

栓内层-1-2层生活细胞,62,63,64,皮孔_周皮上的结构 植物体与外界交换气体的通道65,66,67,（五）分泌结构secretory structure,植物体中能产生特殊分泌物质的细胞或细胞组合称为分泌结构 分为外分泌结构和内分泌结构两类68,外分泌结构,常见的类型有腺毛、腺鳞、盐腺、蜜腺和排水器69,腺毛,腺毛的分泌细胞,70,腺毛（捕蝇草）,Part of a leaf of butterwort, an insectivorous plant. The trichomes secrete enzymes and other compounds that help trap and digest animals.,71,蜜腺：橄榄叶,排水器：甘蓝叶,72,内分泌结构,常存在于基本组织内， 常见的有分泌细胞、分泌腔、分泌道和乳汁管73,有节乳汁管：香蕉叶,无节乳汁管：大戟,74,油腺: 柑橘叶 柠檬叶,75,松木材的树脂道,76,割橡胶,77,木兰叶肉中的油细胞,78,简单组织 Simple tissue 复合组织 Compound tissue,复合组织,复合组织,木质部和韧皮部 维管束,79,维管束 维管束由原形成层分化而来，包括初生木质部、初生韧皮部 (和束内形成层) 组成的束状结构。

复合组织80,有限维管束 木质部和韧成部之间无形成层这类维管束不能再进行发展扩大，称为有限维管束 无限维管束 木质部和韧成部之间保留一层分生组织-束内形成层这类维管束可以继续发展扩大，称为无限维管束81,1外韧维管束，2双韧维管束，3周韧维管束，4周木维管束，5辐射维管束,。