Cellulolytic Activities of Botryodiplodia theobromae Pat

Botryodiplodia theobromae Pat., a ‘stain’ fungusisolated from stained and decaying wood of Bombax buonopozenseP. Beauv., attacked isolated blocks of Bombax wood. In theseit perforated the cell walls and formed elongated cavities withpointed ends, usually in chains, in the secondary wall. Thefungus attacked cellulose in a similar manner to soft rot fungi.It used starch and other saccharides present in the wood ofBombax buonopozense as initial substrates before degrading thecellulose and hemicellulose components of the wood. It did notdegrade the lignin component of the wood. Cellulase, ß-glucosidase, and amylase activities weredetected in culture filtrates of Botryodiplodia theobromae.Cellulase synthesis was delayed when the wood powder in themedium contained starch and saccharides. Amylase, too, behavedlike an inducible enzyme and disappeared from the cultures onexhaustion of starch. Electron microscopy showed that cellulose extracted from thewood of Bombax buonopozense was fragmented into small particleson treatment with the culture filtrates of Botryodiplodia theobromae.Cellobiose, glucose, and another saccharide, probably cellotriose,were identified as the products of enzymatic hydrolysis of cellulose. These results are discussed in relation to the attack and degradationof the wood of Bombax buonopozense by Botryodiplodia theobromaein nature.     

木棉的SSR引物开发

木棉是分布于热带地区的重要经济树种。通过磁珠富集方法开发了木棉的SSR引物,并在采自于西南干热河谷的32个木棉个体中进行了多态性验证。结果表明:这些位点等位基因数量为2～6个,期望杂合度和观测杂合度范围分别为0～0.525和0.121～0.561。仅有一个位点显示Hardy-Weinberg平衡的偏离。这些微卫星标记的开发在木棉属中尚属首次,对于木棉的野生种群遗传多样性研究和木棉遗传资源利用上有很高的潜在价值。     

A Histopathological Study of Anomalous Growth in the Stem of Coccinia indica W. & A. Infested with Neolasioptera cephalandrae Mani

Gall formation due to attack of the larvae of Neolasiopteracephalandrae is common on the stem of Coccinia indica. Isolatedpatches of secondary meristematic centres develop throughoutthe proliferated tissue and they often differentiate into vasculartissues (either xylem or phloem or both). The larvae bore throughthe stem and live in lysigenous cavities in the ground tissue.Proliferation of cells of the secondary meristematic centresresults in gall formation and the normal vascular pattern isdisturbed and vascular bundles crushed. Development of mechanicaltissues in the affected region is suppressed. Additional cambiallayers with no definite pattern of orientation also developin the ground tissue and these produce patches of xylem tissue.Larval cavities are irregular and are surrounded by a nutritivetissue rich in protein and polysaccharides.     

Ultrastructure of the Resin Ducts of Mangifera indica L. (Anacardiaceae). 1. Differentiation and Senescence of the Shoot Ducts

A detailed electron microscope study has led to the conclusionthat the resin ducts of the shoot of Mangifera indica L. developlysigenously. This study has also established several characteristicswhich can serve as criteria for a clear distinction betweenschizogenous and lysigenous cavities. The main characteristicsof lysigenous cavities are: (1) The presence of disorganized cytoplasm in the duct cavity. (2) The presence of wall remains attached to the wall of livingepithelial cells facing the cavity. (3) The presence of specific intercellular spaces at the cellcorners facing the duct lumen. Duct development starts with the disintegration of a file ofcells forming an initial cavity. Later the cells lining thiscavity differentiate into cells secreting lipophilic compounds.As a result of growth and differentiation of the tissues aroundthe duct, its lumen becomes compressed and comes to resemblea branched narrow slit. Such a slit may wrongly be regardedas an initial stage of a schizogenous duct. Disintegration ofepithelial cells occurs throughout all stages of development.Neighbouring cells partly fill the space which is released bydisintegrating cells. At the end of the stage of secretion thecytoplasm of all epithelial cells darkens, preceding their disintegration.This darkening is a gradual process which begins in the vicinityof ribosomes. When all dark epithelial cells disintegrate thecavity widens and the neighbouring parenchyma cells substitutefor the secretory epithelium without undergoing any significantchange in their cytoplasm. Mangifera indica L., mango, resin ducts, ultrastructure     

Cellular pathway of photosynthate transport in coats of developing seed of Vicia faba L. and Phaseolus vulgaris L. II. Principal cellular site(s) of efflux

The cells responsible for the photosynthate efflux from coatsof developing seed of Vicia faba L. and Phaseolus vulgaris L.were elucidated using known properties of the efflux mechanism.Sensitivity of sucrose efflux to NEM and high potassium concentrationswas retained by seed-coat halves of Phaseolus following pectinaseremoval of the branch parenchyma cell layer. In contrast, removalof the thin-walled parenchyma transfer cell layer from Viciaseed-coat halves abolished this sensitivity. The membrane-impermeantthiol-binding fluorochrome, qBBr, selectively stained the surfaceof the thin-walled parenchyma transfer cells. This phenomenonwas inhibited by the slowly permeable sul-phydryl agent, PCMBS,indicating that the plasma membranes of these cells are enrichedin sulphydryl groups characteristic of membrance porter proteins.On the basis that carrier-mediated sucrose efflux from seedcoats appears to be proton coupled, the putative plasma membraneH+-ATPase was used as a marker for the cells responsible forcarrier-mediated photosynthate efflux. When seed-coat halveswere exposed briefly at pH 8.5 to the weak acid fluorochrome,SRG, the ground parenchyma and thin-walled parenchyma transfercell layers selectively accumulated the dye. The apparent lowpH environment in the walls of these cells that renders SRGmembrane permeant appeared to be maintained by a VAN-sensitiveproton pump. The findings with SRG were corroborated by thecyto-chemical localization of plasma membrane ATPase activityto the ground parenchyma and thin-walled parenchyma transfercells using precipitation of cerium phosphate. Together, ourobservations provide qualified support for the conclusion thatcarrier-mediated photosynthate efflux from coats of Phaseolusand Vicia seed is primarily restricted to the ground parenchymaand thin-walled parenchyma transfer cell layers, respectively. Key words: Ground parenchyma, Phaseolus vulgaris L., photosynthate efflux, seed coat, transfer cell, Vicia faba L.     

基于树形结构的木棉叶功能性状差异性研究

叶功能性状不仅反应植物对资源的利用能力,还涉及植物对自身结构和环境的生存适应策略。以不同生长阶段的木棉为研究对象,于2019年12月实地测量树高、冠幅等5个主要树形因子和采样测定叶面积、比叶面积、叶干物质含量、叶片含水量等14个叶功能性状,分析其在不同生长阶段的变化规律和相互关系,探讨叶功能性状对树形结构的响应。结果表明：不同生长阶段的木棉叶功能性状之间存在差异（P<0.05）,且表现出一定的相关性（P<0.05,P<0.01）;木棉叶片的面积、长度、宽度、周长、鲜重、饱和重、干重、比叶质量和干物质含量等功能性状是随生长阶段变化的主要指标。影响木棉叶片各性状的树形因子也不相同,其中叶面积主要受到冠幅的影响,叶片鲜重和饱和重主要受到枝下高的影响,叶片干重和相对含水量主要受到树高的影响,比叶面积、叶片含水量和干物质含量主要受到树高、尖削度的影响,比叶质量主要受到胸径、尖削度、树高的影响。随着木棉的生长,叶功能性状表现出受树形结构的影响而具有较强的表型可塑性,有利于其适应内外环境的变化。因此,叶功能性状之间的变化差异和相关组合,反映了不同生长阶段的木棉对树形结构的适应性调整和对资源的利用策略,在一定程度上为探索西双版纳热带雨林区的生态保护和可持续发展提供相关科学依据。     

Root-knot development in mulberry infested with Meloidogyne incognita

Healthy mulberry roots were inoculated with second stage juveniles of the root-knot nematode, Meloidogyne incognita and the sequential anatomical changes in the root concurrent with the development of the nematode were studied with light and scanning electron microscopes. Visible anatomical changes occurred four weeks post-inoculation when the pear-shaped adult female nematodes appeared in the tissues. The infected roots lost their circular outline and increased in thickness as traumatic parenchyma was induced in the root. The stele was disorganised with reduced and deformed vascular elements. Many giant cells developed in the traumatic tissue, adjacent to the adult females. Eight weeks after the inoculation, cavities developed around the adult females by tissue disintegration, and the galls became discernable on the roots. The number and size of thegalls increased in the next three weeks, corresponding to the development of more traumatic tissues and the enlargement of the adult female nematodes. The majority of the nematodes were settled towards the gall periphery, with their posterior oriented outwards for the release of their eggs into soil by the disintegration of the outer root layers. But many were settled deep inside the gall tissue without a channel to release their eggs to soil. The inner cavities enlarged in large proportions, sometimes occupying the major volume of the gall. The conductive tissues of the root were totally disorganised or were nonexistent.     

Anomalous Growth in the Stem of Ipomoea batatas (L.) Lam. Infested with Megastes Larvae

The stem of Ipomoea batatas (L.) Lam. is characterized by thepossession of a ring of bicollateral, leaftrace bundles. Lacticifersoccur in the pith, in the parenchyma between neighbouring islandsof medullary phloem, and in the cortex. The xylem groups become united by the activity of the inter-fascicularcambium. The production of a certain amount of secondary xylemtakes place before the production of secondary phloem begins.The former is produced more extensively in some areas than inothers, so that the original symmetry of the vascular cylinderis lost. The phellogen originates in the cells of the epidermis. When the stem is attacked by the larvae of Megastes grandalisGuen., which remove most of the internal tissues, anomalousgrowth takes place as a result of the activity of accessorycambia, which develop in the primary cortex, the secondary phloem,and the phelloderm. Residual parenchyma of the pith and/or xylemundergoes hyperplasia to produce a callus tissue which linesthe cavity made by the larvae.     

Early Development of the Seed Coat of Soybean (Glycine max)

Although the development of the soybean ovule has been fairlywell studied, knowledge of the sequence of events in the seedcoat during the first 3 weeks after flowering is incomplete.The goal of the present study was to document, using light microscopy,the early development of the soybean seed coat with respectto changes in structure and histochemistry. At anthesis, theseed coat consists of an outer layer of cuboidal epidermal cellssurrounding several layers of undifferentiated parenchyma (whichtogether constitute the outer integument), and an inner layerof cuboidal endothelial cells (the inner integument). At 3 dpost anthesis (dpa), the inner integument has expanded to includethree to five layers of relatively large cells with thick, heavily-stainingcell walls immediately adjacent to the endothelium. By 18 dpa,the outer integument has developed into a complex of tissuescomprised of an inner layer of thick-walled parenchyma, an outerlayer of thin-walled parenchyma containing vascular tissue whichhas grown down from the lateral vascular bundles in the hilumregion, a hypodermis of hourglass cells, and palisade layer(epidermis). The thick-walled parenchyma of the inner integumenthas become completely stretched and compressed, leaving a single,deeply staining wall layer directly above the endothelium. At21 dpa, the outermost cells of the endosperm have begun to compressthe endothelium. At 45 dpa (physiological maturity) the seedcoat retains only the palisade layer, hourglass cells, and afew layers of thin-walled parenchyma. The innermost layer ofthe endosperm, the aleurone layer, adheres to the inside ofthe seed coat. This knowledge will be invaluable in future studiesof manipulation of gene expression in the seed coat to modifyseed or seed coat characteristics. Copyright 1999 Annals ofBotany Company Soybean, Glycine max, seed coat, development, aleurone.     

Translucent Glands and Secretory Canals in Hypericum perforatum L. (Hypericaceae): Morphological, Anatomical and Histochemical Studies During the Course of Ontogenesis

Hypericum perforatum L., traditionally used in folk medicineas a therapeutic plant, is today being evaluated for its antidepressantand antiretroviral activities. The species is characterizedby the presence of different types of secretory structure: translucentglands or cavities, black nodules and secretory canals. Theaim of this work was to characterize the translucent glandsand secretory canals in both the floral and vegetative parts,from morphological, anatomical and histochemical points of view.Translucent glands consist of a sub-epidermal cavity delimitedby two layers of cells. There are three types of secretory canal:type A, with a narrow lumen, and types B and C, both with awide lumen, but with different patterns of development. Histochemicaltests showed that all these structures contain alkaloids andlipids but not pectic-like substances and proteins. Tests forresins, essential oils and tannins gave different responsesin different parts of the plant. Copyright 2001 Annals of BotanyCompany Hypericum perforatum, St. John's wort, secretory structures, morphology, anatomy, histochemistry     

木棉树形结构和叶性状对生境要素的响应研究

植物形态结构是植物本身与外部环境共同作用的结果。为了分析木棉树形结构与叶性状的相关关系,探索地形、土壤和气象要素对木棉生长的影响,以及揭示木棉的生长策略和适应机制,该文以云南省西双版纳国家级自然保护区内230棵木棉为研究对象,测定6个树形结构指标,8个叶性状指标以及所在区域地形、气象、土壤养分等生境要素,使用结构方程模型和变差分解分析各生境要素对木棉树形结构和叶性状的影响和解释度。结果表明:(1)木棉树形结构各观测指标之间、叶性状各观测指标之间存在相关性(P<0.05)。(2)生境要素各观测指标对木棉生长具有较强影响,其中年均降雨量、坡度、平均温度对木棉生长指标的解释率较高,是影响木棉生长的主要生境指标。(3)从标准化路径系数看,3个生境要素对木棉树形结构和叶性状影响具有一致性,均表现为地形要素>气象要素>土壤要素。(4)3个生境要素叠加解释了树形结构和叶性状分别为43.5%和12.3%,表现出树形结构对生境环境的响应大于叶性状对环境响应的特点。研究结果初步探明了木棉不同生长指标对环境要素的适应策略,为木棉在异质生境的培育、繁殖以及木棉人工林高效经营等提供了理论依据和实践参考。     

DEVELOPMENTAL ANATOMY OF SECRETORY CAVITIES IN THE MICROSPOROPHYLLS OF GINKGO BILOBA L.

Two to five secretory cavities develop in the hump region of the microsporophylls of Ginkgo biloba. A developing cavity is first recognized as a spherical pocket of large, densely cytoplasmic cells (central secretory cells) in the median portion of a microsporophyll primordium. These cells degenerate and a small cavity is formed which is filled with the contents of the degenerating cells. Flattened incurved cells (parietal secretory cells) develop around the disintegrating central secretory cells and slough off into the enlarging cavity. Thus, the cavities develop by lysigeny. A mature cavity is surrounded by senescent parietal secretory cells, scanty parenchyma, and a loosely fitting epidermis. Histochemical tests indicate the presence of lipid and pectic substances in the cavities. Previous reports on the morphological interpretation and possible function role of the cavities are discussed in the light of the present investigation.     

Somatic embryogenesis and plantlet regeneration in semul (<Emphasis Type="Italic">Bombax ceiba</Emphasis>)

Somatic embryogenesis in semul, Bombax ceiba L. (Bombacaceae) was achieved from immature zygotic embryo explants on MS medium. The cytokinin BA induced somatic embryogenesis at higher frequencies than the auxin 2,4-d. The rate of somatic embryogenesis was inversely related to the concentration of BA. A constant supply of 0.44 M BA was necessary for a high multiplication rate. Conversion of somatic embryos into plantlets is reported.     

Comparative Histocytology of the Petiole and the Main Pulvinus in Mimosa pudica L.

In Mimosa pudica, the main pulvinus, which brings about leafmovements, presents unusual structural characteristics in comparisonwith the petiole. Peculiar cellular features which exist inthe cortex, epidermis, parenchyma and endodermal regions includethe shape of the cells, their disposition and the location ofthe organelles. The central cylinder of the petiole is surrounded only by afew parenchyma layers whereas the central cylinder of the pulvinusforms a narrow central core enclosed in numerous cortical parenchymalayers. The phloem of the pulvinus contains collenchymatouscells towards the outside and possesses companion cells withwall ingrowths; these phloem members do not exist in the petiole.Xylem and protoxylem parenchyma cells of the petiole possesswall ingrowths which do not occur in homologous cells of thepulvinus. Moreover the pith of the pulvinus is composed of smallfibriform elements similar to the xylem fibriform elements ofthe organ. The structures observed may facilitate exchanges between cellsin the petiole and in the pulvinus. The predominant functionsof the organs relative to lateral and longitudinal transferof nutrients and conduction of stimuli are discussed. Mimosa pudica L., sensitive plant, pulvinus, ultrastructure, conduction of stimuli, leaf movement     

中国芸香科植物叶分泌囊比较解剖学研究

利用整体透明、石腊和薄切片方法对芸香科22属,40种和2变种植物叶分泌囊的形态结构和分 布进行了比较研究。成熟分泌囊都由鞘细胞和一层上皮细胞围绕圆形腔隙构成,上皮细胞扁平,细胞壁 薄、完整,故分泌囊属裂生方式发生。鞘细胞1～5层,不同种类的层数有变化,个别种缺乏。内层鞘细 胞为扁平的薄壁细胞,外层的细胞壁较厚。分泌囊的形态结构、着生位置和分布密度等在不同属或不同 种间存在一定差异。根据分泌囊在叶中的分布位置和形态结构特点,可将其划分为:叶缘齿缝分泌囊, 叶肉分泌囊和两者混合型。叶肉分泌囊又可分海绵组织分泌囊和栅栏组织分泌囊。在此基础上对该科各类型分泌囊的形态演化关系以及各亚科或各属间的亲缘关系进行了探讨。     

Vascular Occlusions in the Stem of Ailanthus excelsa Roxb.

The stem of Ailanthus excelsa Roxb. (Simaroubaceae) may developvascular occlusions and gum-resin cavities in the xylem as aresponse to injury and infection. Fungal hyphae are observedin the vessel lumen and in the adjacent parenchyma cells. Theocclusions appeared in various forms and showed varying chemicalcomposition. The chemical nature of the occluding material differedfrom that of the exudate formed in the cavities. The majorityof occlusions contained lipids, protein, polysaccharides, phenolics,lignin and probably pectin, whereas, the exudate contained lipids,protein and four soluble sugars. All the components of the occlusionexcept lignin and pectin appear to have been formed in the parenchymacells adjacent to the vessel and migrated to vessel lumen throughthe vessel wall pits. The different constituents migrate intothe vessel lumen independently where they mix to form occlusions. Ailanthus excelsa Roxb., vascular occlusions, lignin, fluorescence, exudation     

Studies on the Structure and Development of Secretory Cavities in Poncirus Trifoliata

Light microscopical observation of thin sections revealed that the initials of secretory cavities in Poncirus trifoliata (L.) Raf. originated from parenchyma cells below the epidermis in early stages of development. The cavity lumen appeared in the center of the initials and gradually enlarged during subsequent development. Concurrently the ceils surrounding the central space differentiated into secretory cells and sheath cells. The developed cavities of fruit ,stem and leaf consisted of 2–5 layers of sheath cells and 2–3 layers of secretory cells surrounding a spherical space. The secretory cells lining the space were observed to remain intact throughout the plantt s life. On the basis of comparative studies with the aid of different kinds of fixatives, embedding media and sectionings,it was suggested that the ,manner of formation of the lacunao of secretory cavities in fruit peels of P. trifoliata, Citrus reticulata and C. sinensis were different. However,as seen in thin sections the secretory cavities of all the 3 species developed schizogenously. Our result with reference to views of other authers concluded the existance of a common schizogenous cavity formation in Rutaceae.     

Plastid and Nuclear DNA in Potato Tuber Tissue 7

On exposure to light the outer parenchyma layers of mature potatobecame green as amyloplasts are converted to chloroamyloplasts.This tissue was sampled during greening, and analysed for nuclearand plastid DNA content. There was an increase in the proportionof plastid DNA in total DNA from 15% in white tuber tissue to22% in greened tissue, while the nuclear ploidy distributionand average nuclear ploidy was similar in both. Key words: Solatium tuberosum, greening, amyloplast     

Ultrastructural Aspects of the Nectary Spur of Limodorum abortivum (L) Sw. (Orchidaceae)

The ultrastructure of the nectary spur of Limodorum abortivum(L) Sw. was examined before and after anthesis. In cross sectionthe nectary spur shows an internal epidermal layer of thin-walledcells bordering the secretory cavity and 10–12 layersof parenchyma cells. The ultrastructure of the secretory cellssuggests the involvement of ER, Golgi and plastids in nectarsecretion. The nectar accumulated in the sub-cuticular spaceis released into the nectariferous cavity by rupture of theouter layer of the cuticle. Limodorum abortivum (L) Sw., Orchidaceae, nectary spur, nectar secretion, ultrastructure, anthesis, endoplasmic reticulum, dictyosomes, plastids