冠盘二胞Marssonina coronaria侵染不同抗性苹果叶片的组织病理学研究

利用光学和电子显微镜,从组织细胞学水平系统研究了冠盘二胞Marssonina coronaria在苹果抗、感病品种叶片上的侵染过程及侵染后寄主细胞的超微结构特征。结果表明：冠盘二胞的侵入和定殖过程可以分为6个阶段：孢子萌发与芽管形成、附着胞形成、侵入细胞角质层、在叶肉细胞内产生吸器、菌丝在叶肉细胞间和细胞内扩展、分生孢子盘形成。随着菌丝扩展,受侵寄主细胞出现细胞壁加厚,细胞壁降解,质壁分离,叶绿体内淀粉粒、嗜饿颗粒积累,叶绿体基粒片层瓦解,线粒体空泡化等现象。在不同抗性的苹果品种上,分生孢子萌发率差别不明     

甾醇生物合成抑制剂粉锈宁对苹果黑星病菌发育的影响

采用电子显微镜和细胞化学技术,研究了杀菌剂粉锈宁（甾醇生物合成抑制剂）对苹果黑星病菌在苹果叶片上发育的影响。观察结果表明,接种前24h施药对病菌入侵有明显的影响。表现为分生孢子的萌发受阻,推迟萌发及萌发率降低;并引起芽管畸形,不能形成附着胞。接种后6天（显症前）施药,可引起叶片角质层下菌丝细胞和子座细胞的原生质坏死、细胞壁不规则增厚及液泡增大, 从而使菌丝进一步发育受阻。接种后12天（显症后）施药,不仅导致菌丝、子座细胞发生上述变化, 而且引起分生孢子和分生孢子梗塌陷、畸形,阻止了病菌的进一步产孢和扩展。细胞化学定位分析结果表明,?-1,3-葡聚糖和几丁质这两种胞壁主要成分在对照菌丝和药剂处理后的菌丝细胞壁内含量有很大差异。在药剂处理的菌丝细胞壁中,这两种成分的标记密度明显高于对照菌丝,表明杀菌剂对病菌质膜透性的不利影响使?-1,3-葡聚糖和几丁质在菌丝细胞壁中过度累积。     

甾醇生物合成抑制剂粉锈宁对苹果黑星病发育的影响

采用电子显微镜和细胞化学技术,研究了杀菌剂粉锈宁（甾醇生物合成抑制剂）对苹果黑星病菌在苹果叶片上发育的影响。观察结果表明,接种前24h施药对病菌入侵有明显的影响。表现为分生孢子的萌发受阻,推迟萌发及萌发率降低。并引起芽管畸形,不能形成附着胞。接种后6天（显症前）施药,可引起叶片角质层下菌丝细胞和子座细胞的原生质坏死、细胞壁不规则增厚及液泡增大,从而使菌丝进一步发育受阻。接种后12天（显症后）施药,不仅导致菌丝、子座细胞发生上述变化,而且引起分生孢子和分生孢子梗塌陷、畸形,阻止了病菌的进一步产孢和扩展。细胞化学定位分析结果表明,β－1,3－葡萄糖和几丁质这两种胞壁主要成分在对照菌丝和药剂处理后的菌丝细胞壁内含量有很大差异。在药剂处理的菌丝细胞壁中,这两种成分的标记密度明显高于对照菌丝,表明杀菌剂对病质膜透性的不利影响使β－1,3－葡聚糖和几丁质在菌丝细胞壁中过度累积。     

小麦雪霉叶枯病菌侵染过程的细胞学研究

采用电镜技术研究了小麦雪霉叶枯病菌(Gerlachia nivalis)侵染过程的细胞学特征。电镜观察发现,分生孢子萌发产生的芽管由孢子细胞壁内层延伸而成;病菌侵入寄主体内后,胞间菌丝先在寄主细胞间扩展,随后胞间菌丝侵入坏死的寄主细胞,形成胞内菌丝;胞间菌丝和胞内菌丝在形态结构上无明显差异。在病菌扩展过程中,寄主细胞发生了一系列的病理变化,并最终坏死消解,寄主细胞的变化可能与病菌分泌的毒素有关。     

小麦雪霉叶枯病菌侵染过程中的细胞学研究

采用电镜技术研究了小麦雪霉叶枯病（Ｇｅｒｌａｃｈｉａｎｉｖａｌｉｓ）侵染过程的细胞学特征,电镜观察发现,分子孢子萌发产生的芽管由孢子细胞壁内层延伸而成,病菌侵入寄主体内后,胞间菌丝先在寄主细胞间扩展,随后胞间菌丝侵入坏死的寄主细胞,形成细胞内菌丝;胞间菌丝和胞内菌丝在形态结构上无明显差异,在病菌扩展过程中,寄生细胞发生了一系列的病理变化,并最终坏死消解,寄主细胞的变化可能与病菌分泌的毒素有关。     

指状青霉Penicillium digitatum侵染柑橘果实的细胞学研究

采用电子显微镜技术系统研究了指状青霉Penicillium digitatum对柑橘果实的侵染过程及超微结构特征。结果表明室温条件下,接种12h后,伤口附近的分生孢子开始萌发产生芽管;然后从伤口处直接侵入果实表皮细胞内;接种24h后,受侵染果实细胞中的菌丝向相邻细胞扩展蔓延,寄主细胞壁开始消解,质壁分离,细胞内含物及各类细胞器凝集,颜色加深,最后完全消解,伤口部位的果皮开始变软,伤口处的菌丝向外生长;84h后伤口处病斑软化,部分长出白色的霉层;96h后病斑软化面积直径达3cm,白色霉层面积逐渐扩大;120h后白色霉层中间伤口处霉层颜色加深变为灰绿色;144h后整个果实变软腐烂。果胶质标记结果表明,菌丝侵入果实后产生果胶酶并降解柑橘细胞壁中的果胶,使得细胞壁松弛,软化腐烂。     

马铃薯对晚疫病水平抗性的组织细胞学观察

以马铃薯晚疫病水平抗性品种LBr-12和感病品种费乌瑞它为材料,采用普通光学和电子显微镜技术,系统研究了马铃薯与晚疫病菌(致病疫霉)互作的组织细胞学反应特征。观察结果显示:(1)接种后,水平抗性材料LBr-12出现过敏反应,病菌被限制在侵染点的几个细胞中,菌丝产生较少的分支和吸器。(2)感病品种费乌瑞它被侵染细胞呈蔓延趋势,菌丝产生较多的分支和吸器。(3)电镜观察发现,抗病品种上病菌的胞间菌丝、吸器母细胞、吸器在细胞和亚细胞水平均发生了一系列异常变化,包括原生质的电子致密度加深、液泡增多变大、菌丝细胞壁不规则增厚、细胞器排列紊乱及解体、吸器母细胞及吸器形态异常、病菌最终畸形坏死,同时发现抗病品种受病菌侵染时可迅速产生结构防卫反应,形成的细胞壁沉积物使胞壁极度增厚或细胞膜上产生乳突状结构。     

黑星病菌在苹果叶片上的发育过程研究

采用电子显微镜技术,研究了苹果黑星病菌在苹果叶片上发育过程。扫描电子显微镜观察结果表明,接种后12 h 分生孢子即可萌发并形成附着胞,统计结果显示其孢子萌发率在6 h和12 h分别为83% 和95%,附着胞形成率在12 h和24 h 分别为93% 和95%。透射电子显微镜观察结果表明,黑星病菌侵入以后在寄主角质层下和表皮细胞之间扩展、定殖并可形成子座。接种后12d,病菌开始从子座上产生分生孢子梗和分生孢子,分生孢子梗顶端每产生一个单生的分生孢子就形成一个环痕并延伸其长度。分生孢子梗和分生孢子主要沿叶脉形成,在叶片上呈网状扩展,此时叶片表现明显的病害症状。     

黑星病菌在苹果叶片上的发育过程研究

采用电子显微镜技术,研究了苹果黑星病菌在苹果叶片上发育过程。扫描电子显微镜观察结果表明,接种后 12h 分生孢子即可萌发并形成附着胞,统计结果显示其孢子萌发率在 6h 和 12h 分别为 83％和 95％,附着胞形成率在 12h 和 24h 分别为 93％ 和 95％ 。透射电子显微镜观察结果表明,黑星病菌侵入以后在寄主角质层下和表皮细胞之间扩展、定殖并可形成子座。接种后12d,病菌开始从子座上产生分生孢子梗和分生孢子,分生孢子梗顶端每产生一个单生的分生孢子就形成一个环痕并延伸其长度。分生孢子梗和分生孢子主要沿叶脉形成,在叶片上呈网状扩展,此时叶片表现明显的病害症状。     

苜蓿假盘菌侵染苜蓿叶片的细胞学研究

采用微分干涉相差显微镜、扫描和透射电镜技术系统研究了苜蓿假盘菌Pseudopeziza medicaginis在苜蓿叶片的侵染过程及超微结构特征。结果表明,接种4h后,子囊孢子萌发产生芽管;12h后,芽管以直接侵入的方式进入表皮细胞形成侵染菌丝;24h后,表皮细胞中侵染菌丝向相邻表皮细胞扩展,同时侵入到叶肉细胞以胞内生长方式扩展;接种72h后,侵染菌丝在表皮细胞下的叶肉组织中形成初始菌落;第5d后,菌丝扩展至整个叶片组织,大量菌丝聚集形成子座组织,并进一步形成子囊盘与子囊。病菌菌丝在侵入寄主细胞初期,并不穿透寄主质膜与原生质,而是被其所包围。但随着菌丝进一步扩展,叶片组织发生了一系列的病理变化,其中包括叶肉细胞肿胀、细胞质消解、叶绿体等细胞器解体以及寄主细胞坏死塌陷,并最终在叶表面产生典型的褐斑病症状。     

木耳菌丝老化过程的微形态学研究

分别从显微和超微结构观察木耳菌种老化过程中菌丝细胞的形态变化。结果显示：接种后30d时,光镜下观察到菌丝结构均匀紧凑,细胞壁光滑;电镜下观察到细胞结构完整,内含物丰富,各种细胞器形态规整,没有老化现象。接种后60d时,光镜下菌丝部分肿胀,色泽加深;电镜下细胞壁疏松,线粒体和液泡肿大,细胞核不规则肿胀,核仁消失,脂肪滴和囊泡增多,并有少量电子致密度高的嗜锇性黑色颗粒状物质出现,表明菌丝开始老化。90d时,光镜下部分菌丝严重肿胀,且色泽更深;电镜下线粒体和液泡肿胀明显,部分细胞核破裂,脂肪滴、囊泡和电子致密度高的嗜锇性黑色颗粒状物质显著增多,细胞壁更加疏松。120d时,光镜下许多菌丝开始断裂,色泽进一步加深;电镜下细胞壁塌陷,膜系统也随之解体,线粒体等细胞器部分溶解消失。150d时,光镜下大部分菌丝完全断裂,并失去菌丝形态;电镜下细胞膜及其内含物已基本消失,只剩部分严重塌陷的细胞壁残骸。由此表明,木耳菌丝的老化是一个由个别向整体逐渐过渡的不可逆的过程。     

Acid invertase is predominantly localized to cell walls of both the practically symplasmically isolated sieve element/companion cell complex and parenchyma cells in developing apple fruits

The acid invertase (β‐fructosidase, EC 3·2·1·26) was localized at subcellular level via immunogold electron microscopy in the phloem‐unloading zone of developing apple fruit. The enzyme (immunogold particles) was found to reside predominantly in the cell walls of the sieve element/companion cell (SE/CC) complex, phloem parenchyma cells and other parenchyma cells. There was almost no gold particle found in cytoplasm and vacuole. This distribution pattern remained unchanged throughout the growing season, but the enzyme numbers varied. The density of immunogold particles increased during fruit development. The immunoblotting of soluble and insoluble acid invertases provided a supporting proof for the assays of immunolocalization. The biochemical analysis showed a predominantly cell‐wall‐distributed activity of acid invertase that corresponds essentially with its amount distribution. The ultrastructural observations showed that there were numerous plasmodesmata between the parenchyma cells, but almost no plasmodesmium between the SE/CC complex and its surrounding parenchyma cells, practically resulting in the symplasmic isolation of the SE/CC complex. It is therefore suggested that the unloading pathway of sucrose from the SE/CC complex may be predominantly apoplasmic in the developing apple fruit, and that the unloaded sucrose may be hydrolysed by the functional acid invertase localized in the cell wall before it is loaded in sink cells.     

Electron microscopy of stages of Isospora felis of the cat in the mesenteric lymph node of the mouse.

Stages of Isospora felis of the cat in the mesenteric lymph node of the mouse 25 days after oral inoculation with oocysts, have been described at the ultrastructural level. The organisms occurred singly within parasitophorous vacuoles in host cell cytoplasm and were sporozoite-like, having a large crystalloid body up to 5.5 mum in length posterior to the nucleus. The size and appearance of the parasitophorous vacuole varied. Some vacuoles contained numerous, small, electron dense granules about 30 nm in diameter. Because of the aggregation of granules and their arrangement within the parasitophorous vacuole, the impression was sometimes gained by light microscopy that parasites were surrounded by a sheath or cyst wall. However, a cyst wall was not present. In host cells, spherical, membrane-bound bodies with a homogeneous, electron dense core and a maximum diameter of 0.25 mum were filed along the limiting membrane of the parasitophorous vacuole. These extra-intestinal parasites were considered to be waiting stages, with a biological function similar to that of the tissue cyst stage of other general of isosporan coccidia.     

葡萄果实发育过程中果肉细胞超微结构的观察

用透射电镜观察了“巨峰”葡萄(Vitis vinifera×V.labrusca)果实3个发育时期中果肉细胞超微结构的变化。果实第一次快速生长期的果肉细胞超微结构表现出物质和能量代谢旺盛的特点。缓慢生长期的果实虽外部形态平静少变,但果肉细胞超微结构表现出深刻的变化:细胞核形状特化为裂瓣状是最显著的特点;线粒体数目丰富;粗面内质网槽库膨大形成的囊泡富集,出现向液泡汇融和向质膜靠近的现象;质膜内陷;液泡膜完整。另外,原生质也出现一些降解的现象。但总体结构特点表明果肉细胞在此期处于十分活跃的物质周转代谢和信息交换过程中。果实第二次快速生长期果肉细胞超微结构表现出衰老降解的特点,但线粒体结构依然完整,数量仍然丰富,原生质膜也保持了很好的完整性,这似乎与维持第二次快速生长或成熟有关。     

Studies on the Character istic of the Structures in the Cortical Cells of Gastrodia clara after Infection of Armillaria mellea

Aided by the techniques of thin and ultrathin sectioning and electron microscopy, the characteristic of structures in the cortical cells of Gastrodia elata was further investigated after infection of Armillaria mellea. It was found that the “hyphal coils”, observed with light microscope, in the cortical cells of G. elata were saccate structures deriv- ed from the cytoplasm of cortical cells and enclosed hyphae. And the cell walls of hyphae were digested in these sacs. Then, these hyphae without cell wall were cut into protoplast fragments in inner-most cortical cells. The results indicated that the cortical cells of G. elata possess digestive function.     

抗病品种中小麦条锈菌细胞的超微结构变化过程

本文就寄主抗病性表达过程中,小麦条锈菌细胞的超微结构变化进行了系统地观察研究。结果表明:胞间菌丝的细胞壁染色逐渐加深,厚度加宽,结构疏松,形成小空洞,并逐渐解体;细胞质逐渐凝聚、脂肪粒的数量增多、有黑色颗粒状沉积物积累;细胞质中小囊泡数目增多并逐渐融合成大液泡,线粒体数目增多,并逐渐肿胀和解体。次生吸器畸形,初生吸器体呈圆球形。吸器壁加厚,染色加深;在吸器的中央,细胞质逐渐分解而形成空泡;线粒体数目增多,并逐渐肿胀和解体;吸器外质膜呈皱褶状,吸器外间质加宽,其中有大量的丝状或颗粒状内含物形成;吸器形态结构的变化均早于其胞间菌丝。     

Penetration of Toxoplasma gondii into host cells induces changes in the distribution of the mitochondria and the endoplasmic reticulum.

Fluorescence microscopy, using dyes which specifically label mitochondria, endoplasmic reticulum and the Golgi complex, and transmission electron microscopy, were used to analyze the changes which occur in the organization of these structures during interaction of Toxoplasma gondii with host cells. In uninfected cells the mitochondria are long filamentous structures which radiate from the nuclear region toward the cell periphery. After parasite penetration they become shorter and tend to concentrate around the parasite-containing vacuole (parasitophorous vacuole) located in the cytoplasm of the host cell. The mitochondria of extracellular parasites, but not of those located within the parasitophorous vacuole, were also stained by rhodamine 123. Labeling with DiOC6, which binds to elements of the endoplasmic reticulum, in association with transmission electron microscopy, revealed a concentration of this structure around the parasitophorous vacuole. The membrane lining this vacuole was also stained, suggesting that components of the endoplasmic reticulum are also incorporated into this membrane. The Golgi complex, as revealed by staining with NBD-ceramide and electron microscopy, maintains its perinuclear position throughout the evolution of the intracellular parasitism.