大叶藤黄叶片的化学成分及其抗氧化活性研究

为了解药用植物大叶藤黄(Garcinia xanthochymus)叶片的化学成分,采用UPLC-QTOF-MS从叶片中得到19个化合物,主要为双黄酮类、黄酮类和间苯三酚类化合物。采用色谱分离法从叶片的80%甲醇提取物中分离得到5个单体化合物,根据理化性质及波谱数据,分别鉴定为二氢山奈酚(1)、dulcisbiflavonoid A (2)、7-去甲基银杏双黄酮(3)、mono-[2-(4-carboxyphenoxycarbonyl)-vinyl]ester (4)、山奈酚(5)。化合物1和2为首次从大叶藤黄中分离得到,化合物3和4为首次从藤黄属植物中分离得到。化合物1和5清除DPPH自由基的IC50值分别为146.8和39.0μg/m L,表明其具有抗氧化活性。     

高效液相色谱法制备人面果中二苯甲酮异构体环大叶藤黄醇和异大叶藤黄醇的研究

本研究报道了一种制备人面果中π键二苯甲酮异构体环大叶藤黄醇和异大叶藤黄醇的液相色谱研究方法。实验中通过色谱柱以及流动相考察,在分析色谱柱上实现了液相方法的建立、模拟及筛选试验,并在半制备色谱柱上实现了放大试验和进样量考察。优化后的色谱条件可实现异构体达到2.5的分离度,并在浓度0.2μg/μL时的进样量达到500μL,单体化合物环大叶藤黄醇和异大叶藤黄醇可通过液相色谱、核磁共振DEPT谱及质谱予以确认。该研究表明,常规C_(18)色谱柱能够对π键异构体进行拆分,将加快更多具有生物活性的二苯甲酮单体化合物的发现。     

PGR-08理化性质及生物活性的研究

PGR-0 8是从某种土壤放线菌 (Actinomyces)的发酵液中分离提纯得到的白色结晶 ,纸层析和熔点检测证明它是化学单体 ,mp 1 80～ 1 81℃ ,[α]2 1D+ 4 3°(H2 O)。溶解性试验表明它易溶于 H2 O(≥ 6 0℃ )、HCl、Na OH、(CH3 ) 2 CO、CH3 OH和 C2 H5OH等 ,但不溶于 Na HCO3 。Tollen、Fehling和 Ag NO3 -溴酚兰等专性试剂的颜色反应表明其组成成分中有嘌呤和糖。生物试验证明 :PGR-0 8具有细胞分裂素的活性 ,例如它能减缓蒲公英离体叶圆片 Chl.的降解 ,延长叶圆片寿命 1～ 2倍以上 ,诱导叶圆片分化出不定根或不定芽 ,甚至建成小植株。它还能促进小麦种子萌发。     

大叶藤黄果的大叶藤黄醇

大叶藤黄(Garcinia xanthochymus Hook.f.ex J.Anders.)又名人面果,岭南倒捻子,最近我们从果分泌的树脂中分离、鉴定了大叶藤黄醇(xanthochmol)。 大叶藤黄醇为黄色针状晶,mp 135℃,IRν_(max)~(KBr).(cm~(-1)):3200—3400(OH),1640—1660,1715(>C=O),3079(C=CH基的νc-H振动),890(末端甲烯基)。 ~1H NMR(WH-90MHz.TMS为内标,CDC_3为溶剂)δ(ppm):1.02,1.17(2s,各3H,>CMe_2),且1.54×2,1.70×2(2s,各6H,—CH=CMe_2×2)。     

硫污染对9种园林植物叶片硫含量与叶绿素荧光参数的影响

对深圳市9种园林植物叶片硫含量,以及硫处理对叶片光合作用参数的影响进行了初步研究。这9种植物分别为红背桂(Excoccaria cochinchinensis)、黄脉爵床(Sanchezia nobilis)、大叶变叶木(Codiaeum variegatum)、基及树(Saruma henryi)、短穗鱼尾葵(Caryota mitis)、小叶榕(Ficus microcarpa var.pusillifolia)、高山榕(Ficus altissima)、海桐(Pittosporum tobira)和黄叶假连翘(Duranta repenscv.\'Dwarf Yellow\')。在温度25℃条件下分别在光照和黑暗条件,用NaHSO₃和蒸馏水浸泡各植物叶圆片24h,共形成4种处理。采用PAM-2100荧光仪测定叶绿素荧光参数。在自然状况下采集的黄脉爵床叶片含硫量最高,远高于其他植物,具有较高的富集能力,含量最低的是大叶变叶木。用蒸馏水浸泡后,9种植物叶片的硫含量的变化很少。在NaHSO₃处理下,有7种植物叶片的硫含量显著提高,增加最多的是自然条件下富集能力最低的大叶变叶木。[0]取自不同大气SO₂污染环境的被测试植物显示,除海桐外,小南山的其它8种植物叶片含硫量都大于世博园植物叶片的含硫量。小南山9种植物的F_v/F_m值也都低于世博园,说明在污染较严重的情况下可以通过测定植物叶片的F_v/F_m值来进行现场监测。     

彩叶凤梨的组织培养及快速繁殖

1　植物名称　彩叶凤梨 (Neoregeliacarolinae)。2　材料类别　茎尖。3　培养条件　 ( 1 )芽的诱导和增殖培养基 :MS +KT 4.0mg·L- 1 (单位下同 ) +IAA 0 .1。 ( 2 )生根培养基 :1 /2MS +IBA 0 .1。以上培养基中附加 3%蔗糖、0 .6%琼脂 ,pH调至 5 .8。培养温度为 2 5～2 7℃ ,光照 1 6h·d- 1 ,光照度为 1 5 0 0～ 2 0 0 0lx。4　生长与分化情况4.1　剥取茎尖　取 8～ 1 0片叶的健壮彩叶凤梨植株 ,流水冲洗干净 ,切去叶片的展开部分 ,保留部分幼嫩叶鞘。用 75 %酒精浸泡 30s ,再用 0 .1 %Hg Cl2 溶液浸泡 8min ,最后用无菌水冲洗 6…     

西双版纳地区附生与非附生植物叶片角质层对水分的透性研究

为了探讨雾水对西双版纳地区不同类型植物的生态学效应,干季于20℃及30℃下用自制的设备测定了西双版纳地区4种附生和4种非附生植物叶片上表皮水分进出角质层的透性,比较研究了不同类型植物叶片通过角质层蒸腾失水速率(P_T)、叶片通过角质层吸水速率(P_A)以及吸水与失水速率的比值(R=P_A/P_T)高低,及其与生活方式的关系。结果表明,附生植物的R值都高于非附生植物且大于1,说明附生植物通过叶片吸收的水分大于蒸腾失水,雾水对于附生植物具有更重要的生态学意义;P_T和P_A在不同植物间有显著差异,这可能与不同植物的角质层化学成分和物理结构不同有关,对其适应各自生活方式及多雾环境有重要意义。除附生植物贝母兰(Coelogyne occultata)和掌唇兰(Staurochilus dawsonianus)以及非附生植物大叶藤黄(Garcinia xanthochymus)外,30℃下其余植物的P_T和P_A都显著高于20℃的,说明温...     

藤黄微球菌降解真菌毒素玉米赤霉烯酮的研究

目的研究并优化藤黄微球菌降解真菌毒素玉米赤霉烯酮(ZEN)的因素条件。方法采用HPLC的检测方法对藤黄微球菌降解真菌毒素玉米赤霉烯酮的影响因素(培养基、温度、pH、摇床转速、培养时间和金属离子等)进行优化研究。结果藤黄微球菌在0.05 mol/LMnCl2、初始pH为7.0的LB培养基中,37℃,180 r/min,连续培养120 h,能降解99%的ZEN毒素(初始浓度为2μg/ml)。结论藤黄微球菌降解真菌毒素ZEN的能力与培养基成分、pH和添加的金属离子种类密切相关。     

断光后的急骤耗氧现象及其与光呼吸的关系(英文)

用氧电极研究叶圆片断光后的耗氧变化,观察到断光后急骤耗氧(rapid postilluminationoxygen consumption RPIOC)现象。在不更换反应液的情况下,随着连续测定次数的增加,烟草叶圆片和番薯叶肉细胞的RPIOC增强。烟草、水稻、番薯、木瓜、黄瓜的叶圆片和番薯叶肉细胞表现出RPIOC,而高粱、甘蔗和玉米则没有这种现象。烟草叶国片的RPIOC随以下因素变化而增强:氧浓度从0.077mmol/L 气相O_27％)增加到 0.230 mmol/L(气相O_2 21％)、光强从111W/m~2增加到350W/m~2、温度从20℃增加到40℃,NaHCO_3(pH7.8)浓度从1 mmol/L(气相CO_2 1188ppm)降低到0.05mmol/L(气相CO_260 ppm)。0.4 mmol/L的HPMS完全抑制烟草叶圆片的RPIOC;10mmol/L的环氧丙酸抑制烟草叶圆片的RPIOC 57.8％。因此认为RPIOC是光呼吸的另一种形式的表现,它对环境因子的变化与已知的影响光呼吸的因子具有一致的反应。     

强酸胁迫下大叶相思幼苗抗性生理机制研究

为探讨大叶相思幼苗耐强酸胁迫的生理机制, 试验采用水培法, 设置了pH 3.0、pH 2.0 和pH 5.8 (CK)酸胁迫梯度和3 天、9 天两个持续胁迫时间, 观测了大叶相思幼苗在不同强度酸胁迫下叶片丙二醛(MDA)含量, 脯氨酸(Pro)含量以及抗氧化酶如过氧化物酶(POD)、谷胱甘肽-S-转移酶(GST)、谷胱甘肽过氧化物酶(GPX)和谷胱甘肽还原酶(GR)等活性的响应特征。结果表明: (1)酸胁迫加重过程中, PSⅡ 最大光化学效率(Fv/Fm)表现出下降趋势; (2)与CK比较, 在pH 3.0胁迫下, Pro无显著变化, 但在pH 2.0 持续胁迫下显著上升, 表明当pH 值低至2.0 时, 大叶相思幼苗受到严重胁迫; (3)与CK 比较, 在pH 值为 3.0和 2.0 持续3 天、9 天的胁迫下, MDA 含量无显著变化, 表明大叶相思幼苗在极强酸胁迫下膜脂过氧化程度并未显著提高; (4)与CK 比较, 在pH 3.0 胁迫下GST 和GPX 活性显著上升, 但在pH 2.0 胁迫下无显著变化; 与CK 比较, 在pH 3.0 胁迫下GR和POD 活性无显著差异, 但在pH 2.0 胁迫下有所下降, 表明大叶相思幼苗体内不同抗氧化酶在应对不同程度强酸胁迫时表现不同, 其中GST 对强酸胁迫响应最为敏感。综合分析各指标在不同梯度酸胁迫下的变化, 认为大叶相思幼苗耐强酸胁迫的生理调节阈值可能在pH 3.0 左右.     

Dispersed cuticles of putative non-vascular plants from the Lower Devonian of Britain

Dispersed cuticles with surface ornamentation recovered from the Lower Old Red Sandstone (Gedinnian) of Hereford and Worcester, England, are described, named and placed in an artificial, morphologically based classification system. Four species of the new genus Cosmochlaina are distinguished on the nature of the ornament. The affinities of the plants covered by such cuticles remain unknown: the cuticles are named to facilitate their use in biogeographic, stratigraphic and evolutionary studies.     

中国植物化石角质层研究综述

总结近30年来中国大陆植物化石角质层研究的进展,介绍角质层分析的3个主要研究方向:植物化石表皮微细构造研究、植物化石气孔参数与大气CO2和气候变化研究以及植物化石角质层地球化学特征研究.举出众多典型实例,提出植物化石角质层分析的研究展望.     

Dispersed cuticles of putative non-vascular plants from the Lower Devonian of Britain

Dispersed cuticles with surface ornamentation recovered from the Lower Old Red Sandstone (Gedinnian) of Hereford and Worcester, England, are described, named and placed in an artificial, morphologically based classification system. Four species of the new genus Cosmochlaina are distinguished on the nature of the ornament. The affinities of the plants covered by such cuticles remain unknown: the cuticles are named to facilitate their use in biogeographic, stratigraphic and evolutionary studies.     

角质层的离析及显微观察方法

植物角质层的离析方法很多,获取化石植物的角质层可以同时用几种化学处理方法。舒氏液浸解是最常用的方法,也是几种方法共用时最关键的步骤。浸解液浓度过大或处理时间过长有可能破坏角质层的结构。对于已经获取到的角质层,利用相差光学显微技术可以增加反差。利用微分干涉光学显微技术不仅反差增加,而且有立体感,背景颜色也可以调节。荧光显微分析技术在不破坏标本的前提下,可以获取到表皮的特征。扫描电子显微镜具有观察不透明物体,放大范围广以及高的分辨力等优越性,可作为光学显微镜的必要补充。     

Trilobite cuticle thickness in relation to palaeoenvironment

100 thickness measurements from thin sections of cephala or pygidia of early Ordovician trilobites occurring across an onshore to offshore environmental gradient show that progressively greater maximum cuticle thickness was characteristic of increasingly inshore sites. There is a 40-fold difference between the thinnest and thickest cuticles, and exclusively thin cuticles are confined to the offshore Olenid Biofacies. Variability in cuticle thickness increases offshore to onshore. Environmental control is shown to be more influential on cuticle thickness than is the overall length of the trilobite: some comparatively large trilobites having thin cuticles and small trilobites thick cuticles. The environmental factors which might be responsible for the pattern are briefly discussed. The thin cuticles dominating the offshore Olenid Biofacies were probably appropriate for dysaerobic conditions. Thick cuticles in the most inshore biofacies may have offered protection against predators and turbulence, but the additional presence there of trilobites with thinner cuticles is considered to reflect the greater heterogeneity of the epeiric habitat.     

Consideration of the importance of hydrophobic interactions in stabilizing insect cuticle

Protein fractions of insect cuticles with different mechanical properties have related values of polarity and hydrophobicity. Hydrophobicity is important for the self-assembly of cuticle which is produced prior to the moult and in plasticization of cuticle. The cuticles of soft-bodied fly larvae are quite distinct from those of exopterygotes (e.g. locusts) and this can be related to the chemistry and mode of tanning. The properties of cuticular proteins are compared: the proteins of the pliant cuticles most closely resemble globulins, and the proteins in stiff cuticles are more like fibrous and hydrophobic structural proteins. Changes in the environment of the proteins may alter their shape and hence the mechanical properties of the cuticle.     

Ultrastructural studies of fossil plant cuticles: Ticoa harrisii from the early Cretaceous of Argentina

ARCHANGELSKY, S., TAYLOR, T. N. & KURMANN, M. H., 1985. Ultrastructural studies of fossil plant cuticles: Ticoa harrisii from the early Cretaceous of Argentina. The fine structure of fossil plant cuticles of Cretaceous age demonstrates well preserved layers that are topographically equivalent to those in some extant plants. Cuticle stratification on specialized structures (stomatal apparatus and trichomes) is presented, together with an account of the fine structure of both the upper and lower cuticular membrane. Levels of cuticle stratification are compared with those of extant plants.     

植物角质层生物学特性及水分渗透性研究进展

植物角质层作为植物体与外界环境的第一道保护屏障, 其最主要的功能是防止植物体过度失水。揭示植物角质层的生物学功能及其原理将为现代农业的发展以及仿生材料的开发应用提供科学指导。该文综述了植物角质层的生物学特性及其与水分渗透性关系的研究进展, 并展望了角质层水分渗透研究的应用前景。     

Lognormal distribution of water permeability and organic solute mobility in plant cuticles

It is shown that water permeabilities and organic solute mobilities in plant cuticles have a lognormal distribution. Seven-hundred and fifty values for rate constants of desorption (～mobility) of 2,4-D from isolated Citrus aurantium L. cuticles from a population of leaves were pooled and analysed. A histogram of the rate constants of individual cuticles showed a skew distribution with a strong tail to higher values. Cuticular membranes with high values did not differ from others in visual appearance and were not leaky. After log-transformation of original data an almost perfect normal distribution was obtained. Statistical tests showed that a normal distribution of original values is not acceptable. Inspection of older data for water permeability in the same species and experiments using large samples of cuticles from leaves of Pyrus communis L. and Stephanotis floribunda Brongn. and from fruits of Capsicum annuum L. showed a similar distribution, as did inspection of data for experiments with organic solutes. A lognormal distribution was found for cuticles of plants from growth chambers, glasshouses and outdoors as well as for water permeability of intact leaves of Hedera helix L. For small samples the overestimation from using the arithmetic mean of original data can be high, but use of the geometric mean or the median leads to smaller deviations. Removing cuticular waxes from cuticles produced normally distributed samples. A normal distribution was also obtained when organic compounds which increase solute mobility were sorbed into cuticles.     

Stiffness and tanning of sclerites

Tensile studies on cuticle of different chitin fibre architecture indicate that the intimate relationship between physical stiffness and the extent of chemical tanning holds for those cuticles which are mechanically isotropic in their surface planes, but not for those which are mechanically anisotropic.