紫胶虫外部形态扫描电镜观察

本文是用紫胶虫酒浸死虫标本进行光学显微镜和扫描电镜观察研究的结果。记述了该虫雌成虫的体形大小和肛上板，膊器、前气门、背刺、口器、触角、后气门、阴门、围阴腺群，周缘腺群、腹管腺群等形态特征，并与有关文献的记述进行了比较，以供有关部门和人员参考。     

Simultaneous measurements of quantum yield and CO2 uptake for the assessment of non-assimilative electron flow in tree leaves

Using attached and detached leaves ofAcer palmatum Thunb. andRhaphiolepsis umbellata Makino, pulse-modulated chlorophyll fluorescence and CO₂ exchange were measured. Quantum yield of photosynthesis was determined from the fluorescence parameter(Fm′−Fs)/Fm′, where (Fm′−Fs) was defined as the difference between steady state chlorophyll fluorescence (Fs) and maximum fluorescence (Fm′) elicited by a saturating light pulse. The rate of electron transport through photosystem II (total electron flow) was calculated from the product of quantum yield andA (PFD), whereA is the rate of absorbed photons as given by leaf absorptance, and PFD is the photon flux density at the leaf surface. The rate of electron transport dependant on CO₂ uptake (assimilative electron flow) was calculated from the gross photosynthetic rate in a leaf. The difference between the rates of total and assimilative electron transport was denoted as the rate of non-assimilative electron transport which depends on photorespiration and oxygen reduction. Available data provided quantitative information on the rate of non-assimilative electron flow in intact leaves. When leaf photosynthesis ofA. palmatum was measured under sunlight, the rates of total and assimilative electron transport were determined to be approximately 900 and 150 μmol equiv. e/mg Chl·h, respectively. The difference (750 μmol equiv. e/mg Chl·h) was attributed to the activity of non-assimilative electron flow. The ratio of total to assimilative electron flow was found to increase gradually with rising in irradiance. The results suggest that non-assimilative electron flow occurred at much higher rate than assimilative electron flow at high irradiance. Implications of the results are briefly discussed in relation to photosynthesis limitation in tree leaves.     

Delignification of cell walls of <Emphasis Type="Italic">Chamaecyparis obtusa</Emphasis> during alkaline nitrobenzene oxidation

To clarify the behavior of whole lignins in wood cell walls during alkaline nitrobenzene oxidation, the delignification process from cell walls in normal and compression woods of Chamaecyparis obtusa Endl. (Cupressaceae) was observed using ultraviolet and transmission electron microscopies. The lignin content conspicuously decreased to around 10% after 35min in normal wood. The lignin content in compression wood finally leveled off at aroumd 10% after 50min. In gel filtration of oxidation products in ethyl acetate, a high molecular weight fraction was prominent in extracts from the early stage of the reaction. As the oxidation progressed, the high molecular weight fraction became less prominent in both normal and compression wood. Changes in the weights of cell wall residues during reaction indicated that approximately half of the components other than lignin were also removed from the cell walls. This shows that the majority of lignin with relatively high molecular weight is removed from the cell walls together with polysaccharides in the early stage of the reaction and that further oxidative degradation occurs in solution in later stages. Only a small amount of the lignin with low molecular weight could be analyzed by gas chromatography.Parts of this report were presented at the 47th (Kochi, April 1997) and 48th (Shizuoka, April 1998) Annual Meetings of the Japan Wood Research Society, and at the Lignin Symposium, Sapporo, October 1997     

碱蓬和盐地碱蓬花粉形态研究及其在分类上的贡献

借助光学显微镜和扫描电镜研究了碱蓬属2种植物碱蓬和盐地碱蓬的花粉形态，并对不同生境条件下盐地碱蓬4变式的花粉形态进行了对比研究，研究结果表明：花粉粒外部形态成球形；大小在15.4-24.0μm之间；具有散萌发孔，萌发孔数量在46－55之间，萌发孔直径为3．1－5．4μm；花粉粒表面光滑，其上散布许多颗粒状小突起，萌发孔上亦有数目不等的小突起。以上数值在不同种间有较明显的差异，在盐地碱医宵同生态变式间亦有差异，但差异较小。这些细微的特性差异可为碱蓬属植物分类提供参考依据，是研究该属植物分类及生态的新资料。     

Toxicological effects and recovery of the corneal epithelium in Cyprinus carpio communis Linn. exposed to monocrotophos: an scanning electron microscope study

This study was conducted based on the evidence of fish habitats in North India being affected by organophosphate pesticides draining from agricultural fields into bodies of water, especially during the rainy season. Various tissues of fish such as scales, gills ovaries, kidney, and liver have been studied from the toxicological point of view, but the toxicological effects of aquatic pollutants on fish cornea have not been investigated to date. We conducted comparative toxicological studies on the cornea of Cyprinus carpio communis using two sublethal (0.038 and 0.126 ppm) concentrations of monocrotophos pesticide for 30 days. Corneas from all the groups were evaluated by a scanning electron microscope. The fish exposed to the monocrotophos pesticide developed corneal necrosis due to the formation of crystalloid‐like structures, thinning and shrinkage of microridges on the corneal epithelium. After 30 days, fish from the monocrotophos‐treated tank were transferred to normal environmental conditions. After 60 days under natural condition, epithelial cells did not fully recover. In conclusion, exposure to monocrotophos induces irreversible changes in the cornea of C. carpio communis. As fish and mammalian visual systems share many similarities, the reported finding may offer useful insights for further toxicological and ophthalmological studies in humans.     

Frozen bread dough: Effects of freezing storage and dough improvers

This review focuses on the effects of freezing storage on the microstructure and baking performance of frozen doughs, and provides an overview of the activities of dough improvers, including emulsifiers, hydrocolloids and other improvers used in frozen dough applications. The overall quality of bread baked from frozen dough deteriorates as the storage of the dough at sub-zero temperatures increases due to several factors which are discussed. Lipid-related emulsifiers such as diacetyl tartaric acid esters of mono and diglycerides and sucrose esters employed as anti-staling agents, dough modifiers, shortening sparing agents, and as improvers for the production of high-protein bread have also been employed in frozen doughs. Hydrocolloids are gaining importance in the baking industry as dough improvers due to their ability to induce structural changes in the main components of wheat flour systems during breadmaking steps and bread storage Their effects in frozen doughs is discussed. Other dough improvers, such as ascorbic acid, honey and green tea extract, are also reviewed in the context of frozen doughs.     

毛竹和重组竹腐朽前后的表面颜色及耐腐性能

以毛竹和重组竹为研究对象,用绵腐卧孔菌(PV)、密粘褶菌(GT)两种褐腐菌和彩绒革盖菌(CV)、变色栓菌(TV)两种白腐菌进行腐朽试验,比较分析了毛竹和重组竹腐朽前后表面视觉性质及其质量损失差异。结果发现:毛竹和重组竹颜色均发生了显著变化,主要表现为明度(L~*)降低,色度值(C)、红绿轴色品指数(a~*)和黄蓝轴色品指数(b~*)显著增大,其中绵腐卧孔菌对毛竹及重组竹的色差影响最大。重组竹(耐绵腐卧孔菌)能达到Ⅰ级强耐腐水平;毛竹(耐绵腐卧孔菌)和重组竹(耐密粘褶菌和彩绒革盖菌)达到了Ⅱ级耐腐水平;毛竹(耐密粘褶菌、彩绒革盖菌和变色栓菌)和重组竹(耐彩绒革盖菌)为Ⅲ级稍耐腐水平。整体来看,重组竹对白腐菌和褐腐菌的耐腐效果好于毛竹。绵腐卧孔菌虽然对毛竹和重组竹的降解能力最弱,但对其颜色变化的影响却最大。扫描电镜可观察到彩绒革盖菌通过毛竹导管壁上的纹孔进入薄壁细胞、伴胞等,同时通过分泌木质素酶导致其细胞壁降解。     

光镜及扫描电镜下波纹龙虾血淋巴细胞的形态及其分类

光镜及扫描电镜下,研究波纹龙虾血淋巴细胞的组织学结构、形态学特征和数量。根据细胞质中颗粒存在与否,颗粒数量的多少,细胞体积的大小及外部形态,对波纹龙虾的血淋巴细胞进行分类。结果表明,光镜下波纹龙虾的血淋巴细胞有3种类型:无颗粒细胞,小颗粒细胞,大颗粒细胞;这3种血淋巴细胞不是连续发育过程中血淋巴细胞的不同阶段,而是彼此独立的。3种血淋巴细胞的数量占循环血淋巴细胞总量的比例分别为:无颗粒细胞占57.1%,大颗粒细胞占24.9%,小颗粒细胞占18.0%;在扫描电镜下,细胞表面不平,有各种突起,揭示细胞具有活跃的变形运动和吞噬能力。血淋巴细胞形态有球形、卵圆形和椭圆形。     

不同培养条件对鸭源鸡杆菌生物被膜形成的影响

采用体外定量法检测20株鸭源鸡杆菌的被膜形成能力,并对被膜形成能力较强的1株鸭源鸡杆菌在不同环境（培养时间、培养基质、营养条件）下产生生物被膜（BF）的差异进行了研究。结果显示,大部分鸭源鸡杆菌均具有不同程度形成被膜的能力,其中3株被膜形成能力中等,2株形成能力较强;鸭源鸡杆菌在银染法、试管法和微量板定量检测法中形成BF的最佳培养时间分别是24、60、24h。其生长周期为8h开始起始黏附、20h大量黏附阶段、24h时形成了完整的生物被膜、32h生物被膜老化散播,之后起始新一轮的被膜周期。葡萄糖、蔗糖及NaCl的加入均在一定程度上抑制了被膜的形成,且随着加入量增加NaCl对被膜形成抑制更显著,而低质量浓度的MgSO4在一定程度上促进BF的形成。扫描电镜观察发现,生物被膜内鸭源鸡杆菌聚集成团状、相互黏连形成致密的三维立体结构。