广西金花茶木材解剖研究

本文对采自广西的14种金花茶木材进行解剖研究。管孔类型为散孔材至似半环孔材;木射线二列为主。全为异形组织;结晶体丰富。而且只存在于方形或直立射线细胞中。在射线细胞或轴向薄壁细胞腔中,可见一些细胞核及细胞质。细胞核的出现与物种的生态环境有关,生长于石灰土的金花茶,其木材中可见细胞核,而生长于酸性土的则不见。     

大豆属植物茎的次生木质部结构研究

利用光学显微技术和扫描电镜技术,对大豆属Clycine L.的4种类型植物茎材进行比较解剖学研究.结果表明,4种类型植物的茎材横切面均为散孔材。野生大豆茎材多为单管孔.少见复管孔;半野生大豆具复管孔,少见多细胞的管孔链;半栽培大豆茎材中复管孔和管孔链较多;而栽培大豆的复管孔和管孔链更多且普遍.野生大豆单列射线多,多列射线少半野生大豆有少数多列射线;半栽培大豆多列射线较多;栽培大豆多列射线细胞组成的射线最多.大豆种植物的次生木质部导管的侵填体分布不同,各种结构的演化途径为野生大豆→半野生大豆→半栽培大豆→栽培大豆野生大豆结构较原始,栽培大豆最进化.     

HO·和γ射线对细胞致死效应的比较

利用双链断裂模型比较研究了羟自由基和γ射线对B16、L0 2、SMMC - 772 1和V79四种细胞的致死效应。结果表明 :1.HO·处理和γ射线照射对四种细胞有都明显的致死效应 ,而且剂量越大致死作用越强。 2 .HO·处理和γ射线照射存活曲线都存在肩区 ,说明两种处理过程都有亚致死损伤的修复。 3.HO·诱导DNA双链断裂一般都需要两次击中而γ射线辐照既有一次击中的成分 ,也有两次击中的成分。 4.四种细胞对HO·的敏感性与对γ射线的辐射敏感性顺序相反 ,说明γ射线对细胞的作用不能简单地解释为自由基的行为。     

不同发育阶段斑马鱼胚胎对X射线辐射敏感性差异

目的:考察X射线对斑马鱼早期胚胎发育的影响,探讨其影响机制.方法:用X射线照射不同发育时段的斑马鱼胚胎,统计死亡率和畸形率;应用单细胞凝胶电泳(SCGE)技术检测X射线对胚胎DNA损伤的影响;采用DCFH-DA测定胚胎活性氧;总抗氧化能力(T-AOC)测定;结果:X射线照射对斑马鱼胚胎发育有明显的影响,能够导致胚胎发育畸形如围心腔水肿、脊柱扭曲、尾部弯曲等多种畸形甚至死亡;检测X射线对斑马鱼胚胎DNA损伤时,发现X射线照射对胚胎中的DNA能够产生明显的损伤,且DNA损伤程度随胚胎发育的进行而减弱;胚胎经X射线照射后活性氧的产生增加;胚胎总抗氧化能力随着胚胎发育的进行而逐渐增强;结论:X射线照射明显影响斑马鱼胚胎发育,并造成胚胎细胞DNA损伤,发育早期胚胎敏感性高;发育后期胚胎对X射线敏感性降低,可能与胚胎细胞抗氧化能力增强有关.     

蛋白质分子的构象运动及其功能意义

 <正> 自从五十年代末成功地运用X射线衍射分析技术测定肌红蛋白分子的晶体结构以来,我们关于蛋白质在三维水平的结构及其与功能关系的认识,已经历了两个阶段。第一个阶段包括60年代初至70年代中期。在这一期间,解决了蛋白质晶体结构测定方法的一般化问题,使以同晶置换法为主的一套X射线衍射分析技术成为研究生物大分子三维结构的成熟手段,给     

不同纬度对鹅掌楸次生木质部结构的影响

对生长在北纬23至32度的鹅掌楸〖WTBX〗（Liriodendron chinense〖WTBZ〗 Sarg.）的次生木质部进行了比较解剖学研究。观察的特征有：导管分子的长度、直径、壁厚、梯状穿孔板横闩的数目;导管密度、纤维长度、直径、壁厚;射线的高度、宽度,单列射线的比例,射线的密度等。结果表明,随着纬度的增加,导管分子变短变细,壁变薄,梯状穿孔板的横闩数目减少;纤维也变短变细,壁变薄;木射线变矮变窄,单列射线的比例和射线密度增加。     

砷超富集植物中砷化学形态及其转化的EXAFS研究

通过同步辐射扩展X射线吸收精细结构(SR EXAFS)研究砷超富集植物大叶井口边草(Pteris nervosa)中砷的化学形态及其在植物体中的转化. 结果表明, 在大叶井口边草中砷主要与O配位, 根部存在与谷胱苷肽(GSH)结合的砷, 但是在羽叶中没有发现与GSH结合的砷. 在NaAsO₂和Na₂HAsO₄处理中, 植物根系的砷分别以As(Ⅲ)和As(Ⅴ)为主, 但是在叶柄和羽叶中砷都以As(Ⅲ)的形态为主. 植物根系吸收的As(Ⅴ)在向上转运的过程中具有向As(Ⅲ)转化的趋势, 其转化过程主要发生在根部. 实验证明, 与GSH结合并不是大叶井口边草中砷解毒的主要机理, 超富集植物可能具有与一般耐性植物不同的重金属解毒机制.     

不同纬度对鹅掌楸次生木质部结构的影响

对生长在北纬23至32度的鹅掌楸（Liriodendron chinense Sarg.）的次生木质部进行了比较解剖学研究。观察的特征有：导管分子的长度、直径、壁厚、梯状穿孔板横闩的数目;导管密度、纤维长度、直径、壁厚;射线的高度、宽度,单列射线的比例,射线的密度等。结果表明,随着纬度的增加,管分子变短变细,壁变薄,梯状穿孔板的横闩数目减少;纤维也变短变线,壁变薄;木射线变敌变窄,单列射线的比例和射线密度增加。     

60Co-γ射线辐射对柞蚕生物学特性的影响

利用~(60)Co-γ射线对柞蚕卵进行辐射,探讨了~(60)Co-γ射线辐射对柞蚕生物学特征的影响.结果表明:120 Gy以下辐射剂量对柞蚕卵孵化率及柞蚕死亡率影响不大,但随着~(60)Co-γ射线辐射剂量的增加,孵化率明显降低而死亡率显著升高;血液蛋白质图谱和相关基因序列在辐射前后亦存在差异.这些生物性状的改变说明~(60)Co-γ射线对柞蚕生长发育具有重要的影响.     

大豆属植物茎的次生木质部结构研究

利用光学显微技术和扫描电镜技术,对大豆属ClycineL.的4种类型植物茎材进行比较解剖学研究．结果表明,4种类型植物的茎材横切面均为散孔材。野生大豆茎材多为单管孔．少见复管孔;半野生大豆具复管孔,少见多细胞的管孔链;半栽培大豆茎材中复管孔和管孔链较多;而栽培大豆的复管孔和管孔链更多且普遍．野生大豆单列射线多,多列射线少半野生大豆有少数多列射线;半栽培大豆多列射线较多;栽培大豆多列射线细胞组成的射线最多．大豆种植物的次生木质部导管的侵填体分布不同,各种结构的演化途径为野生大豆→半野生大豆→半栽培大豆→栽培大豆野生大豆结构较原始,栽培大豆最进化     

Response of Xylem Ray Parenchyma Cells of Red Osier Dogwood (Cornus sericea L.) to Freezing Stress (Microscopic Evidence of Protoplasm Contraction)

Freezing behavior of wood tissue of red osier dogwood (Cornus sericea L.) cannot be explained by current concepts of freezing resistance. Previous studies indicated that water in wood tissue presumably froze extracellularly. However, it was observed that xylem ray parenchyma cells within these tissues could survive temperatures as low as -80[deg]C and the walls of these cells did not collapse during freezing (S.R. Malone and E.N. Ashworth [1991] Plant Physiol 95: 871-881). This observation was unexpected and is inconsistent with the current hypothesis of cell response during freezing. Hence, the objective of our study was to further examine the mechanism of freezing resistance of wood tissue of red osier dogwood. We studied freezing stress response of xylem ray parenchyma cells of red osier dogwood using freeze substitution and transmission electron microscopy. Wood samples were collected in winter, spring, and summer of 1992. Specimens were cooled from 0[deg]C to -60[deg]C at 5[deg]C/h. Freezing stress did not affect the structural organization of wood tissue. However, the xylem ray parenchyma cells showed two unique responses to a freezing stress: protoplasm contraction and protoplasm fragmentation. Protoplasm contraction was evident at all freezing temperatures and in tissues collected at different times of the year. Cells with fragmented protoplasm, however, were noticed only in tissues collected in spring and summer. Protoplasm contraction in winter tissue occurred without apparent damage to the protoplasm. In contrast, protoplasm contraction in spring and summer tissues was accompanied by substantial damage. No evidence of intracellular ice formation was observed in parenchyma cells exposed to freezing stress. Differences in protoplasm contraction and appearance of cells with fragmented protoplasm likely indicated seasonal changes in cold hardiness of the wood tissue of red osier dogwood. We speculate that the appearance of fragmented protoplasm may indicate that cells are being injured by an alternative mechanism in spring and summer.     

五种金花茶组植物的耐寒性比较研究

金花茶组植物是世界珍稀、濒危的观赏植物,具有极高的观赏价值和药用价值.为了比较金花茶组植物的耐寒性,以五种金花茶组植物为材料,采用人工模拟低温环境的方法对其2年生叶片进行低温胁迫处理,应用电导法研究五种金花茶种质在20℃(常温对照)、8℃、-2℃、-7℃、-12℃、-17℃、-22℃和-27℃低温下相对电导率的变化,配合Logistic方程,测定其低温半致死温度(LT50),以及叶片中游离脯氨酸、可溶性糖和丙二醛的含量.结果表明:五种金花茶的低温半致死温度(LT50)范围为-14.58~-12.74℃,其中金花茶为-14.58℃、龙州金花茶为-14.27℃、柠檬黄金花茶为-13.44℃、直脉金花茶为-13.09℃、东兴金花茶-12.74℃.低温半致死温度能反映金花茶种质的耐寒性,金花茶和龙州金花茶耐寒性强,其次为柠檬黄金花茶和直脉金花茶,东兴金花茶耐寒性较弱.在降温过程中,五种金花茶叶片相对电导率随温度降低呈S型上升,与温度呈负相关;脯氨酸、可溶性糖和丙二醛含量均呈现先上升后下降的趋势.同一低温条件下,半致死温度低的金花茶脯氨酸和可溶性糖的含量更高,而丙二醛含量更低.该研究结果为金花茶组植物耐寒种质选育提供了科学依据,为人工种植金花茶提供了技术支持.     

Living Cells in Wood 3. Overview; Functional Anatomy of the Parenchyma Network

The very different evolutionary pathways of conifers and angiosperms are very informative precisely because their wood anatomy is so different. New information from anatomy, comparative wood physiology, and comparative ultrastructure can be combined to provide evidence for the role of axial and ray parenchyma in the two groups. Gnetales, which are essentially conifers with vessels, have evolved parallel to angiosperms and show us the value of multiseriate rays and axial parenchyma in a vessel-bearing wood. Gnetales also force us to re-examine optimum anatomical solutions to conduction in vesselless gymnosperms. Axial parenchyma in vessel-bearing woods has diversified to take prominent roles in storage of water and carbohydrates as well as maintenance of conduction in vessels. Axial parenchyma, along with other modifications, has superseded scalariform perforation plates as a safety mechanism and permitted angiosperms to succeed in more seasonal habitats. This diversification has required connection to rays, which have concomitantly become larger and more diverse, acting as pathways for photosynthate passage and storage. Modes of growth such as rapid flushing, vernal leafing-out, drought deciduousness and support of large leaf surfaces become possible, advantaging angiosperms over conifers in various ways. Prominent tracheid-ray pitting (conifers) and axial parenchyma/ray pitting to vessels (angiosperms) are evidence of release of photosynthates into conductive cells; in angiosperms, this system has permitted vessels to survive hydrologic stresses and function in more seasonal habitats. Flow in ray and axial parenchyma cells, suggested by greater length/width ratios of component cells, is confirmed by pitting on end walls of elongate cells: pits are greater in area, more densely placed, and are often bordered. Bordered pit areas and densities on living cells, like those on tracheids and vessels, represent maximal contact areas between cells while minimizing loss of wall strength. Storage cells in rays can be distinguished from flow cells by size and shape, by fewer and smaller pits and by contents. By lacking secondary walls, the entire surfaces of phloem ray and axial phloem parenchyma become conducting areas across which sugars can be translocated. The intercontinuous network of axial parenchyma and ray parenchyma in woods is confirmed; there are no “isolated” living cells in wood when three-dimensional studies are made. Water storage in living cells is reported anatomically and also in the form of percentile quantitative data which reveal degrees and kinds of succulence in angiosperm woods, and norms for “typically woody” species. The diversity in angiosperm axial and ray parenchyma is presented as a series of probable optimal solutions to diverse types of ecology, growth form, and physiology. The numerous homoplasies in these anatomical modes are seen as the informative results of natural experiments and should be considered as evidence along with experimental evidence. Elliptical shape of rays seems governed by mechanical considerations; unusually long (vertically) rays represent a tradeoff in favor of flexibility versus strength. Protracted juvenilism (paedomorphosis) features redirection of flow from horizontal to vertical by means of rays composed predominantly or wholly of upright cells, and the reasons for this anatomical strategy are sought. Protracted juvenilism, still little appreciated, occurs in a sizeable proportion of the world’s plants and is a major source of angiosperm diversification.     

十四种金花茶组植物叶总黄酮含量比较

金花茶叶含有丰富的黄酮类化合物.以70%乙醇为提取溶剂,对14种金花茶叶中的黄酮进行超声波提取,并以芦丁为对照品,采用紫外分光光度法于273 nm处测定吸光度,得出各种金花茶叶总黄酮的含量并进行了比较.结果表明:不同种金花茶叶黄酮的含量差异较大,平果金花茶中新叶的总黄酮含量(22.011%)最高,而东兴金花茶中一年叶龄...     

广西金花茶叶解剖

<正> 金花茶是世界珍稀的观赏植物,仅分布于广西一隅。自从金花茶被发现之后,金花茶的新分类群不断增加,导至中山大学张宏达教授于1981年在《中山大学学报(自然科学)论丛(1)》的专著中建立了金花茶组(sect Chrysantha Chang),该组共包含9个分类群。近年来新的金花茶分类群仍陆续被发现,目前金花茶组的分类群己达到20个以上。蒋承曾等     

广西金花茶花粉形态

<正> 本文报道广西金花茶(Camellia Sect.Chrysanthae)8个种1个变种花粉在光学显微镜和电子扫描显微镜下观察的结果。 材料和方法 材料取自在广西采集的腊叶标本上的花粉。制片方法采用G.Erdtman的醋酸酐分解法,在光学显微镜下测量其大小。扫描电镜观察材料采用醋酸酐分解,后用蒸馏水洗净,再用纯酒精脱水,上铜台,喷金,在扫描电子显微镜下观察并照相。     

广义锦葵科火绳树属4个种的枝条木材解剖及其分类学意义

研究了广义锦葵科火绳树属4个种枝条的木材解剖。火绳树属枝条为散孔至半环孔材,管孔主要为单管孔和2～3个管孔组成的径列复管孔;导管间纹孔式和射线导管间纹孔式互列、小;侵填体和螺纹加厚缺如。射线主要为单列射线,2～3列射线较多;射线细胞多为方形,射线组织主要为异型,边缘直立细胞常1行;射线组织稀为同型;鞘细胞和瓦形细胞缺如。轴向薄壁组织傍管和离管型,主要为带状。晶体丰富,主要在射线、纤维和薄壁组织中。研究的4个种可以通过枝条木材解剖特征加以区分。     

山茶科系统发育诠释——Ⅲ.关于金花茶组及山茶属演化若干问题

作者通过比较认为山茶属金花茶组的模式和古茶组的模式不是同一分类单位,因而取消金花茶组是不恰当的。金花茶组是一个自然的集合体。作者详细地分析了山茶属内演化的四个阶段:第一阶段表现为苞被不分化、大型、宿存、子房5室、心皮部分分离;第二阶段演化出苞被宿存和苞被脱落两个类群,前者较为原始的代表是离蕊茶织和短蕊茶组,较为进化的代表是管蕊茶组;后者较为原始的代表是半宿萼茶组、瘤果茶组、糙果茶组,较为进化的代表是油茶组、短柱茶组、红山茶组;第三阶段是苞被分化为小苞片和萼片的类群,金花茶组和长柄茶组是较为原始而茶组、超长柄茶组则是较为进化的代表;第四阶段的连蕊茶组和毛蕊茶组苞萼小型化且宿存,的代表,雌、雄蕊均高度连合,子房室不完全发育 它们只能由第三阶段具有多数小苞片的原始类群发展出来,认为把山茶属划分为四个亚属的系统是合理的。 作者还认为,花的颜色以及其他相似性状的集合是划分山茶属次级分类单位的重要依据;分类系统的自然性和实用性相结合是分类学家始终应该追随的目标,混淆不同差异的做法是不可取的。最后,作者认为山茶属没有真正的顶生花。     

8种木本旱生植物的木质部解剖学特性研究

从生态学角度对8种旱生植物木材的次生木质部结构进行了对比研究.结果表明,8树种次生木质部结构的共同特点为:生长轮分界明显(霸王和四合木的年轮有时不连续),半环孔材,单穿孔,导管壁间纹孔互列,木纤维无横隔膜,联合傍管轴向薄壁组织丰富,导管壁上呈现螺纹加厚,都具有异型射线;它们主要差异在于射线和导管的数量化指标:四合木异型射线1~2列,霸王、白刺、沙冬青和胡枝子射线2~5列,柽柳、柠条和花棒大型射线4~10列;导管分子长度和纤维长度在树种间和同一树种个体间差异较明显.四合木和沙冬青导管频率较大,导管管孔较小,因此Vulnerability和Mesomorphy值也较小,更能适应干旱环境.