Ultrastructural and Cytochemical Studies of 'Air Blisters' in Pilea cadierei Gagnep. and Guillaumin

Cells from the sub-epidermal layer of Pilea cadierei preparedfor electron microscopy using standard fixation and embeddingprocedures appear extremely osmiophilic, with the organellesstanding out in negative relief. However, when tissues werefixed in glutaraldehyde supplemented with either procaine orcaffeine (substances known to complex with phenols) the osmiophilicmaterial was generally limited to the vacuole. After procaineor caffeine fixation the surrounding cytoplasm appeared as inadjacent, nonphenolic cells. Some small aggregates of phenolicmaterial appear in the cisternae of the endoplasmic reticular,indicating these organelles may be involved in either the synthesisor transport of phenolics in Pilea. Since one of the major functionsof phenolics is in light-screening, air blisters may serve toscreen out damaging radiation from the underlying tissue. Thepresence of typical shade-type plastids in Pilea air blistersis a further indication of this light-screening role. Pilea cadierei, aluminium plant, air blister, cytochemistry, ultrastructure, light screening, phenolics     

Cystolith Development and Structure in Pilea cadierei (Urticaceae)

Cystolith formation, structure and composition have been investigatedin leaves and stem internodes of Pilea cadierei (Urticaceae)using a variety of techniques at the light and electron microscopelevels. The development of lithocysts from epidermal cells hasbeen followed. These cells are cytoplasmically similar to otherepidermal cells but possess a much more active Golgi apparatusand more numerous mitochondria. The cystolith is a spindle-shapedbody composed of concentric layers of longitudinally orientatedcellulose microfibrils associated with pectins and other cellwall polysaccharides. At maturity it is heavily impregnatedwith calcium carbonate. Some cystoliths also contain siliconand are covered in a sheath of siliceous material. Cystolithformation occurs at the tip of a peg that grows in from thelithocyst wall. Evidence from ultrastructure suggests that thelithocytst cytoplasm transports carbohydrates to the cystolithvia Golgi vesicles, and organizes the deposition of cystolithcellulose microfibrils via a system of microtubules lying beneaththe plasma membrane that envelopes the growing cystolith. Thepeg is composed of heavily staining amorphous material likethat of an apoplastically sealed cell wall. It is incapableof supporting the migration of lanthanum ions into the cystolith.We conclude that cystoliths are isolated volumes of apoplastthat act as repositories for inorganic salts, principally calciumcarbonate. We propose that calcium ions move into the lithocystprotoplast from surrounding cells and are then transported acrossthe plasma membrane boundary into the cystolith. This proposalconflicts with previous suggestions that calcium enters by diffusionthrough the peg. Cystolith, lithocyst, cell wall, calcium, silicon, cytochemistry, electron probe analysis, Pilea cadierei     

Distribution of Lithocysts, Trichomes, Hydathodes and Stomata in Leaves of Pilea cadierei Gagnep. & Guill. (Urticaceae)

In leaves of Pilea cadierei lithocysts, trichomes and hydathodesin the upper epidermis, and lithocysts, trichomes and anomocyticstomata in the lower epidermis are components of a regular distributionpattern in which spacing probably depends upon inhibitory interactionsbetween initial cells during leaf development. Anisocytic stomata,which also occur in the lower epidermis, show a clumped distributionpattern that results from their relatively late formation aftercell division in the epidermis is otherwise complete, and fromthe inhibitory influence of established lithocysts, trichomesand anomocytic stomata. Ordered spacing of anisocytic stomatawithin groups probably results from mutual inhibition betweeninitial cells at the time of inception. Lithocysts associatedwith primary and secondary veins are elongated along the veinaxis. Elsewhere in the leaf lithocyst, orientation is obliquerelative to the midrib and shows a correlation with vein orientationaround the time of lithocysts elongation. Lithocyst, cystolith, trichome, hydathode, stomata, Pilea cadierei     

Microtubules and epithem-cell morphogenesis in hydathodes of Pilea cadierei

When cell divisions have ceased, the epithem of the hydathodes of Pilea cadierei Gagnep. et Guill. consists of small polyhedral cells exhibiting a meristematic appearance, and completely lacks intercellular spaces. The cortical microtubules in epithem cells exhibit a unique organization: they are not scattered along the whole wall surface but form groups lying at some distance from each other. In sections, from two to eight groups of microtubules can be observed, each lining a wall region averaging between 0.5 and 1.5 m in length. These groups represent sections of microtubule bundles girdling a major part or the whole of the cell periphery. They are connected to one another by anastomoses, forming a microtubular reticulum. The assembly of microtubule bundles is followed by the appearance of distinct local thickenings in the adjacent wall areas. The cellulose microfibrils in the thickenings are deposited in parallel to the underlying microtubules. Gradually, the vacuolating epithem cells undergo swelling, except for the areas bounded by the wall thickenings. Since the latter, and actually their constituent bundles of cellulose microfibrils, cannot extend in length the differential cell growth results in schizogenous formation of intercellular spaces between contiguous cell walls at their thickened regions. The spaces then broaden and merge to become an extensive intercellular space system. As a result of the above processes, the epithem cells become constricted and finally deeply lobed. The observations show that (i) the cortical microtubules are intimately involved in the morphogenesis of the epithem cells and (ii) the initiation and development of the epithem intercellular spaces is a phenomenon directly related to cell morphogenesis and therefore to the cortical microtubule cytoskeleton. The sites of initiation of these spaces are highly predictable.     

Comparative anatomy of Platanus kerrii Gagnep.

The vegetative anatomy of Platanus kerrii Gagnep. Is described and compared with other Platanus species. Platanus kerrii is anatomically clearly a representative of Platanus but its xylem exhibits the most primitive characters in the series of species studied, closely followed, however, by P.chiapensis. A possible relationship with the fossil P.neptuni is discussed, but anatomical data of the latter species are too sparse to draw any well-founded conclusion. Differences in epidermal pattern support the suggestion (Kvacek, 1969) that P.kerrii and P.neptuni are at least distinct species.     

尖叶石仙桃的胚培养与快速繁殖

1植物名称尖叶石仙桃(Pholidota missionariorum Gagnep.)。2材料类别蒴果内的种子。3培养条件尖叶石仙桃种子萌发培养基     

峨眉含笑试管培养再生植株

1植物名称峨眉含笑(Michelia wilsonii Finet et Gagnep.)。2材料类别侧枝的顶芽。3培养条件诱导培养基:(1)MS 6-BA 1 mg·L~(-1) (单位下同) NAA 0.2;增殖培养基:(2)MS 6- BA 0.3 NAA 0.3;生根培养基:(3)1/2MS NAA 0.5 IBA 0.5。诱导培养基和增殖培养基加入3%蔗     

Assimilation and translocation of nitrogen and carbon in Curcuma alismatifolia Gagnep

Curcuma or Siam tulip (Curcuma alismatifolia Gagnep.) is an ornamental flowering plant with two underground storage organs, rhizomes and storage roots. Characteristics of N and C assimilation and transport in curcuma were investigated. The plants were treated with ¹⁵NH₄⁺ + ¹⁵NO₃^? and ¹³CO₂ at 10, 13 or 21 weeks after planting. Plants were sampled at several stages up to 32 weeks. The C stored in old storage roots was used rapidly during the first 10 weeks; after which N stored in old rhizomes and old storage roots were used. The daily gain in C depending on photosynthesis was remarkably high between 10 and 21 weeks. However, the daily gain in N was relatively constant throughout the growth period. The ¹⁵N absorbed at 10 weeks was initially accumulated in leaves and roots, but some was transported to flowering organs at 13 weeks. At harvest, 41% of ¹⁵N was recovered in new rhizomes and 17% in new storage roots. After ¹³CO₂ exposure at 10 and 13 weeks, the distribution of ¹³C among organs was relatively constant in subsequent stages. When given ¹³CO₂ at 21 weeks, a large amount of labelled C was recovered in new storage roots and new rhizomes at harvest. Both new rhizomes and new storage roots stored N and C, however, rhizomes played a more important role in supplying N, while storage roots provided C.     

光照强度对金果榄光合特性和生长品质的影响

目的:探讨不同光照强度对金果榄植株光合特性和生长的影响.方法:设置光照强度为自然光强的100％、52.7％、33.2％和15.8％四种处理,测定其光合速率等生理指标、叶绿素、生物产量及活性成分含量的变化.结果:1.低光照强度处理的光合速率均高于100％自然光照处理,33.2％处理最高,显著地高于52.7％处理和15.8...     

Studies on the Development of the Air Pores and Air Chambers of Marchantia paleacea: 1. Light Microscopy

The ontogeny of the air pores and air chambers of Marchantiapaleacea begins with the schizogenous development of protodermalintercellular spaces of the initial apertures, and is completedwith the formation of the air pores and giant sub-epidermalair chambers bearing numerous photosynthetic filaments. Intercellularspace formation commences from the thallus surface and proceedsinwards to the first internal layer of cells. The cells amongwhich spaces develop do not originate from one mother cell.Spaces are formed only in the regions of the intersection ofthe anticlinal walls of three, four, or sometimes more successivederivatives of S₁, S₃ and S₄ segments of the apical cell, oneor two of which have been divided periclinally and the restanticlinally. Protodermal intercellular spaces appear in mostor all the corners of these cells, the anticlinal walls of whichexhibit an opposite disposition. The S₁, S₂, S₃ and S₄ segmentsare produced by definite divisions of a five-sided apical celland by a series of divisions give rise to initial cells of theinternal layers of the thallus and initial cells of the protodermaland sub-protodermal layers. The concept of a quiescent apicalcell cannot be accepted, since dividing apical cells have beenobserved, and the pattern of wall disposition of the thallusapex cannot be explained without the active participation ofthe apical cell. The air chambers are apparently of exogenous origin. They resultfrom the broadening of the bottom of the initial apertures bythe coordination of the rate of anticlinal divisions and growthof the protodermal and sub-protodermal cells surrounding theintercellular spaces of the initial apertures. The ontogenyof the pore rings starts at an advanced stage of air chamberformation not from a mother cell but from the cells which surroundthe closed entrance of the air chamber, by a shift of the planeof division from anticlinal to periclinal. Before the periclinaldivisions a new axis of growth perpendicular to the thallussurface is established in the mother cells of the pore. By a polarized growth into the air chamber followed by periclinaldivisions, the cells of the floor form initial cells of thephotosynthetic filaments. The latter divide again to form singleor branched photosynthetic filaments. Marchantia paleacea, air pore, air chamber     

Development of the Laryngeal Air Sac in Chimpanzees

Though many nonhuman primates possess a laryngeal sac, the great apes are unique in their great size. Though an enlarged sac probably arose in their common ancestor, its functional adaptations remain a matter of debate. Its development in extant great apes is likely to provide valuable information to clarify the issue. We used magnetic resonance imaging to examine the development of the laryngeal sac in 3 living chimpanzees, age 4 mo–5 yr, and identified 2 distinct growth phases of the sac. A gradual growth of the sac in early infancy results in a configuration so that it occupies the ventral region of the neck; many adult nonhominoid primates having a sac show the configuration. The subsequent rapid expansion of the sac in late infancy causes the final configuration in chimpanzees, wherein the sac expands into the pectoral, clavicular, and axillary regions. The latter phase possibly arose at latest in the last common ancestor of extant great apes and contributed to the evolution of the enlarged sac, despite the later evolutionary diversification in adult sac anatomy and growth. As many studies have advocated, the enlarged sac probably plays a role in vocalization in adults. However, physiological modifications in the laryngeal region during infancy are likely to provide valuable information to evaluate the functional adaptations of the enlarged sac in the great apes.     

石油菜挥发油和超临界流体萃取物化学成分的GC-MS分析

首次利用水蒸气蒸馏法和超临界流体萃取法(SFE)对石油菜地上部位进行提取,分别获得挥发油和SFE萃取物,采用气相色谱-质谱联用技术(GC-MS)结合计算机数据库检索对这两种提取物的化学成分进行了分析鉴定,采用峰面积归一化法测定了其中各个化学成分的相对含量。从挥发油中共分离出39个色谱峰,鉴定了其中28个化学成分,已鉴定出的成分的相对含量总和占化合物检出总量的91.90%,化合物类型均为萜类。从SFE萃取物中共分离出136个色谱峰,鉴定了其中65个化学成分,已鉴定出的成分的相对含量总和占化合物检出总量的58.17%,化合物类型包括萜类、芳香族类和脂肪族类。挥发油和SFE萃取物均含有α-蒎烯、石竹烯和桉油烯醇,其他成分则存在较大差异。     

Antioxidant and radioprotective effect of the active fraction of Pilea microphylla (L.) ethanolic extract

The ethanolic extract of Pilea microphylla (L.) was defatted, successively fractionated with acetone and the residue so obtained was found to be most potent when subjected to detailed free radical scavenging and in vivo radioprotection studies. The most active fraction reacts with free radicals, such as DPPH (50 microM), ABTS(.)(-) (100 microM) and (.)OH (generated by Fenton reaction) with IC(50) value of 23.15 microg/ml, 3.0 microg/ml and 310 microg/ml, respectively. The most active fraction inhibited iron-induced lipid peroxidation in phosphatidyl choline liposomes with an IC(50) of 13.74 microg/ml. The kinetics of scavenging of DPPH and ABTS(.)(-) radicals were followed at different concentrations of the fraction by employing stopped-flow studies. The observed first order decay rate constants at 200 microg/ml and 50 microg/ml of fraction with DPPH (50 microM) and ABTS(.)(-) (50 microM) were found to be 0.4s(-1) and 2.1s(-1), respectively. The fraction when screened for in vivo radioprotection in Swiss albino mice showed 80% protection at a dose of 900 mg/kg and with a DRF of about 1.12. The fraction was also found to protect livers of irradiated mice from depletion of endogenous antioxidant enzymes like glutathione, GST, SOD, catalase and thiols. The fraction also protected the villi height, increased the number of crypt cells while offering general protection to the intestine from acute radiation effects. The fraction also protected the hematopoietic system as assessed by endogenous spleen colony assay, contributing to the overall radioprotective ability.     

Air pollution and health.

The effects of air pollution on human health are reviewed. Data from toxicology, epidemiology, clinical and laboratory exposures are presented as a basis for an emerging etiology. Sulfur dioxide, suspended particulates, nitrogen dioxide, photochemical oxidants, and carbon monoxide are examined as stress agents to the cardio-pulmonary system.     

Stepwise Development of a Positive Long Spark in the Air

Plasma Physics Reports - A spark discharge is modelled in a long air gap of atmospheric pressure at a positive voltage with a long front duration, excluding the quasi-continuous development of the...