Mucilage Cells, Calcium Oxalate Crystals and Soluble Calcium in Opuntia ficus-indica

The subcellular location of soluble calcium in parenchymatousand mucilage cells of Opuntia ficus-indica was determined histochemically.Soluble calcium was observed in crystal chambers containingcalcium oxalate on the membrane of the vesicles. Calcium wasalso present in the plasmalemma, in plasmodesmata, in cell walls,in mitochondria and in the vacuoles. Especially marked was thepresence of soluble calcium in vesicles free or fused with theplasmalemma. Little free calcium was observed in other cellcompartments. In the calcium economy of tissues the location of soluble calciumand the transport of calcium to and from mucilage cells to parenchymatouscells and calcium oxalate idioblasts will play a role. Chelationof calcium by mucilage or oxalate, which depends on pH, ionicstrength, etc., will be important in this respect. Opuntia ficus-indica, calcium oxalate, mucilage cells, transport of calcium     

植物草酸钙晶体的形成和功能

草酸钙晶体在植物中普遍存在,其形成是一种基本的生理过程。总结了目前对草酸钙晶体的生化、结构、形成、调控以及在植物生长发育过程中所起作用等方面的研究进展。     

Calcium Oxalate Crystals in Developing Seeds of Soybean

Young developing soybean seeds contain relatively large amountsof calcium oxalate (CaOx) monohydrate crystals. A test for Caand CaOx indicated that Ca deposits and crystals initially occurredin the funiculus, where a single vascular bundle enters theseed. Crystals formed in the integuments until the embryo enlargedenough to crush the inner portion of the inner integument. Crystalsthen appeared in the developing cotyledon tissues and embryoaxis. All crystals formed in cell vacuoles. Dense bodies andmembrane complexes were evident in the funiculus. In the innerintegument, cell vacuoles assumed the shape of the future crystals.This presumed predetermined crystal mould is reported here forthe first time for soybean seeds. As crystals in each tissuenear maturity, a wall forms around each crystal. This intracellularcrystal wall becomes contiguous with the cell wall. Integumentcrystals remain visible until the enlarging embryo crushes theinteguments; the crystals then disappear. A related study revealedthat the highest percent of oxalate by dry mass was reachedin the developing +16 d (post-fertilization) seeds, and thendecreased during late seed maturation. At +60 d, CaOx formationand disappearance are an integral part of developing soybeanseeds. Our results suggest that Ca deposits and crystals functionallyserve as Ca storage for the rapidly enlarging embryos. The oxalate,derived from one or more possible metabolic pathways, couldbe involved in seed storage protein synthesis. Copyright 2001Annals of Botany Company Calcium, crystals, development, Glycine max, ovule, oxalate, seed, soybean     

Calcium,Calcium Oxalate Crystals,and Leaf Differentiation in the Common Bean (Phaseolus vulgaris L.)*

Young plants of Phaseolus vulgaris were grown in nutrient solutions at different levels of calcium concentration. When the calcium concentration was low more palisade parenchyma and less extended bundle sheath was formed at the adaxial side of minor veins of the leaves as compared to leaves of plants grown with higher calcium supply. The number of calcium oxalate crystals in the bundle sheath extensions was positively correlated to the amount of calcium fed to the plants. The ion induces additional cell divisions in the bundle sheath extensions. A high supply of calcium leads to the formation of a second type of crystal in the bundle sheath.     

Calcium Oxalate Raphide Crystals and Crystalliferous Idioblasts in the Carpels of Ornithogalum caudatum

Crystalliferous idioblasts commonly are found in groups of twoor three cells in the peripheral region of the carpels Crystals,composed of calcium oxalate, usually are m well-organized bundleswhich develop within a matrix of protein and carbohydrate inthe vacuole of each idioblast The matrix occurs around and betweenindividual crystal chambers and contains spheres and tubules5.4 nm in diameter The matrix changes in character and locationwith age Crystals form within their own individual chambers,each comprised of a series of lamellae The number of lamellaeis variable The innermost lamella is different from the othersin that it is apparently continuous The other lamellae are platelikeand superficially resemble successive periderms. The lamellaemay begin and/or terminate abruptly or they may anastamose Eachlamella is composed of chains of spheres about 6 1 nm in diameterand is separated from adjacent lamellae by tubules 5.4 nm indiameter Both the crystals and slime body are absorbed duringlater stages of carpel maturation. Ornithogalum caudatum Ait carpel, calcium oxalate, idioblasts, ultrastructure     

Calcium Oxalate Crystals in Monocotyledons: A Review of their Structure and Systematics

Three main types of calcium oxalate crystal occur in monocotyledons:raphides, styloids and druses, although intermediates are sometimesrecorded. The presence or absence of the different crystal typesmay represent ‘useful’ taxonomic characters. Forinstance, styloids are characteristic of some families of Asparagales,notably Iridaceae, where raphides are entirely absent. The presenceof styloids is therefore a synapomorphy for some families (e.g.Iridaceae) or groups of families (e.g. Philydraceae, Pontederiaceaeand Haemodoraceae). This paper reviews and presents new dataon the occurrence of these crystal types, with respect to currentsystematic investigations on the monocotyledons. Copyright 1999Annals of Botany Company Calcium oxalate, crystals, raphides, styloids, druses, monocotyledons, systematics, development.     

The Occurrence, Type and Location of Calcium Oxalate Crystals in the Leaves of Fourteen Species of Araceae

The occurrence, type and location of calcium oxalate crystalsin the leaves of 14 species belonging to the family Araceaewere studied by light microscopy. The Pizzolato test and theRubeanic acid-silver nitrate test, used to chemically identifyand locate the crystals in cross sections of laminae, showedthe presence of four types of crystals: druses, raphides, prismaticsand crystal sand. Styloids were not observed in any of the species.Crystals identified as calcium oxalate were observed in eachtissue layer of the leaf blade, druses occurring more frequentlyin the palisade mesophyll layers, raphides more often in thespongy mesophyll. Prismatics were sparse, occurring in the mesophyllof only two species. Specialized spindle-shaped crystal idioblasts,located in the spongy mesophyll in all cases, were observedin seven of the 14 aroids. Crystal sand and variations in crystalforms were most frequently observed to be calcium compoundsother than calcium oxalate. Crystals, calcium oxalate, idioblasts, Araceae     

草酸钙结晶在几种凤仙花属植物中的特征及其分类学意义

首次研究了7种凤仙花属(ImpatiensL.)植物茎的解剖学及细胞组织中草酸钙结晶的特征.结果表明,7种凤仙花属植物茎的解剖学结构非常近似,而茎中草酸钙结晶特征则差异显著,7种凤仙花属植物茎中均有草酸钙针晶,根据草酸钙结晶形态特征的不同,将针晶分为3种类型,即针晶束、针晶簇和散针晶.其中,黄金凤、长角凤仙花、锐齿凤仙花和红纹凤仙花有针晶束分布,而湖北凤仙花、紫花黄金凤和窄萼凤仙花则无针晶束分布,只有针晶簇或散针晶分布;此外,针晶的形态、长度、排列方式及丰富程度等在不同的物种中亦有差异.草酸钙结晶特征对凤仙花属植物的分类具有一定的科学意义.     

Interspecific hybridisation and interaction with cultivars affect the genetic variation of Ulmus minor and Ulmus glabra in Flanders

Interspecific hybridisation and gene flow from cultivated plants may have profound effects on the evolution of wild species. Considering the cultural history and past use of Ulmus minor and Ulmus glabra trees in Flanders (northern Belgium), we investigated the extent of human impact on the genetic variation of the remaining, supposedly indigenous elm populations. We therefore examined the rate of interspecific hybridisation, which is expected to be higher under human influence, the occurrence of clones within and among locations, the presence of cultivars and their possible offspring. Based on results produced using 385 amplified fragment length polymorphic (AFLP) markers, 46 % of the 106 investigated Flemish elms appeared to be F1 hybrids or backcrosses to one of the parent species, while no F2 hybrids (F1?×?F1 progeny) were found. Clonality was mainly found among U. minor and hybrids, which are more likely to form root suckers or sprouts as opposed to U. glabra. The majority of the studied locations (76 % of the locations with multiple samples) showed evidence of clonal reproduction. Several, sometimes distant, locations shared a multilocus lineage. We also found indications of gene flow from cultivated elms into native species. It is conceivable that reproductive material has been moved around extensively, obscuring the natural genetic structure of the elm populations. The results help guide the Flemish elm genetic resources conservation programme.     

Induction of Nitrate Assimilatory Enzymes in the Tree Betula pendula

The coordinate appearance of the bispecific NAD(P)H-nitrate reductase (NR; EC 1.6.6.2) and nitrite reductase (NiR; EC 1.7.7.1) was investigated in leaves and roots from European white birch seedlings (Betula pendula Roth). Induction by nitrate and light of both enzymes was analyzed by in vitro assays and by measuring NR- and NiR-encoding mRNA pools with homologous cDNAs as probes. When birch seedlings were grown on a medium containing ammonium as the sole nitrogen source, low constitutive expression of NR and NiR was observed in leaves, whereas only NiR was significantly expressed in roots. Upon transfer of the seedlings to a nitrate-containing medium, mRNA pools and activities of NR and NiR dramatically increased in leaves and roots, with a more rapid induction in leaves. Peak accumulations of mRNA pools preceded the maximum activities of NR and NiR, suggesting that the appearance of both activities can be mainly attributed to an increased expression of NR and NiR genes. Expression of NR was strictly light-dependent in leaves and roots and was repressed by ammonium in roots but not in leaves. In contrast with NR, constitutive expression of NiR was not affected by light, and even a slight induction following the addition of nitrate was found in the dark in roots but not in leaves. No effect of ammonium on NiR expression was detectable in both organs. In leaves as well as in roots, NiR was induced more rapidly than NR, which appears to be a safety measure to prevent nitrite accumulation.     

Histochemical Localization of Calcium Oxalate Crystals in Starch Grains of Yams (Dioscorea)

The bulbils and/or tubers of seven species of yams (Dioscorea)were examined for crystal content using light microscopy andhistochemistry. Calcium oxalate crystals in the form of raphide bundles werelocalized in the parenchymatous tissues. Within starch grains,crystals of various shapes and sizes were observed. The variationin shape and sizes of the intra-amylar crystals could be exploitedfor taxonomic purposes. Calcium oxalate crystals appear to serve a storage functionin these starch grains. Yams, Dioscorea, raphides, oxalate crystals, histochemistry     

Investigation of daily mitotic activity of the birch, Betula pendula Roth

A study was made of the daily mitotic activity in the seedling root meristem of birch trees growing in an ecologically clear area--the biological station of Voronezh State University "Venevitinovo". The peak of mitotic activity was exposed at 9 a. m. (according to winter time). The rise of mitotic index was noted at 9 and 12 p. m. due to an increase in the share of cells being in the prophase stage, and to a high number of dividing cells with persistent nucleoli. A possibility of prolongation of the mitotic cycle time is supposed to be due to cell delay in prophase stage, which may be associated with anthropogenic and nature-climatic influences on the original trees themselves and on their seed progeny. This makes it possible to consider the investigated region as only conventionally clear, because of the availability of a high recreative pressure upon the trees.     

MLO-Associated Decline of Alnus glutinosa, Populus tremula and Crataegus monogyna

In the Heidelberg area of southwestern Germany declining trees of Alnus glutinosa (L.) Gaertn. and Populus tremula L. as well as stunting shrubs of Crataegus monogyna Jacq. were observed. In all 3 species mycoplasmalike organisms, which appear to be the causal agents of the disorders, were detected by fluorescence and electron microscopy. The diseases of alder and aspen seem to be lethal while the hawthorn apparently is less affected.     

Macropinocytosis is the Major Mechanism for Endocytosis of Calcium Oxalate Crystals into Renal Tubular Cells

During an initial phase of kidney stone formation, the internalization of calcium oxalate (CaOx) crystals by renal tubular cells has been thought to occur via endocytosis. However, the precise mechanism of CaOx crystal endocytosis remained unclear. In the present study, MDCK renal tubular cells were pretreated with inhibitors specific to individual endocytic pathways, including nystatin (lipid raft/caveolae-mediated), cytochalasin D (actin-dependent or macropinocytosis), and chlorpromazine (CPZ; clathrin-mediated) before exposure to plain (non-labeled), or fluorescence-labeled CaOx monohydrate (COM) crystals. Quantitative analysis by flow cytometry revealed that pretreatment with nystatin and CPZ slightly decreased the crystal internalization, whereas the cytochalasin D pretreatment caused a marked decrease in crystal uptake. Immunofluorescence study and laser-scanning confocal microscopic examination confirmed that the cytochalasin D-pretreated cells had dramatic decrease of the internalized crystals, whereas the total number of crystals interacted with the cells was unchanged (crystals could adhere but were not internalized). These data have demonstrated for the first time that renal tubular cells endocytose COM crystals mainly via macropinocytosis. These novel findings will be useful for further tracking the endocytosed crystals inside the cells during the course of kidney stone formation.     

Calcium Oxalate Crystals: An Integral Component of the Sclerotinia sclerotiorum/Brassica carinata Pathosystem

Oxalic acid is an important virulence factor for disease caused by the fungal necrotrophic pathogen Sclerotinia sclerotiorum, yet calcium oxalate (CaOx) crystals have not been widely reported. B. carinata stems were infected with S. sclerotiorum and observed using light microscopy. Six hours post inoculation (hpi), CaOx crystals were evident on 46% of stem sections and by 72 hpi on 100%, demonstrating that the secretion of oxalic acid by S. sclerotiorum commences before hyphal penetration. This is the first time CaOx crystals have been reported on B. carinata infected with S. sclerotiorum. The shape of crystals varied as infection progressed. Long tetragonal rods were dominant 12 hpi (68% of crystal-containing samples), but by 72 hpi, 50% of stems displayed bipyramidal crystals, and only 23% had long rods. Scanning electron microscopy from 24 hpi revealed CaOx crystals in all samples, ranging from tiny irregular crystals (< 0.5 μm) to large (up to 40 μm) highly organized arrangements. Crystal morphology encompassed various forms, including tetragonal prisms, oval plates, crystal sand, and druses. Large conglomerates of CaOx crystals were observed in the hyphal mass 72 hpi and these are proposed as a strategy of the fungus to hold and detoxify Ca²⁺ions. The range of crystal morphologies suggests that S. sclerotiorum growth and infection controls the form taken by CaOx crystals.     

Translocation and Metabolism of Picloram and 2,4-D in Populus tremula

Translocation and metabolism of 4-amino-3,5,6-trichloropicolinic acid (picloram) and 2,4-dichlorophenoxyacetic acid (2,4-D) in small plants of aspen (Populus tremula L.) were studied. In most experiments ¹⁴C-carboxyl-labelled herbicides were used. Considerable quantities of both herbicides were retained in the treated leaf. Translocation was mainly upwards into the growing shoot tip. Only minute quantities were found in the roots. Injection of the herbicides through a cut stem surface increased the translocation into the roots very little. One of the reasons for the limited downward translocation is considered to be a ready transfer of the herbicides between the phloem and the xylem. Both herbicides were incorporated into complexes from which the active herbicides could be released. However, this complex formation can only partly account for the retention of the herbicides in the treated leaves. The differences in metabolism found between 2,4-D and picloram cannot explain the considerable difference in toxicity between the compounds.     

Carbon isotope discrimination and wood anatomy variations in mixed stands of Quercus robur and Quercus petraea

The two most common oak species in western Europe, Quercus robur and Quercus petraea, display different ecological behaviours, particularly with respect to their responses to drought. The ecophysiological basis of this niche difference is not understood well. Here we test the hypothesis that these two species present distinct water use efficiencies (WUEs), using the carbon isotope discrimination approach. Leaves and 13 dated ring sequences were sampled in 10 pairs of adult trees growing side by side. Carbon isotope composition was measured on cellulose extracts. In addition, relationships between carbon isotope discrimination and wood anatomy were assessed at the tree level. Quercus robur displayed a 1·0‰ larger isotopic discrimination than Q. petraea, and therefore a lower intrinsic WUE (?13%). This interspecific difference of isotopic discrimination was quite stable with time and independent of tree radial growth and climate fluctuations. A strong positive correlation was observed between average tree values of earlywood vessel surface area and ¹³C isotopic discrimination. This correlation was even higher with ¹³C of the 1976 dry year (r = 0·86). These observations led to the hypothesis that hydraulic properties of xylem could exert a constraint on leaf gas exchange, resulting in a larger WUE for individuals with smaller vessel cross‐section area.     

Peptides of Matrix Gla Protein Inhibit Nucleation and Growth of Hydroxyapatite and Calcium Oxalate Monohydrate Crystals

Matrix Gla protein (MGP) is a phosphorylated and γ-carboxylated protein that has been shown to prevent the deposition of hydroxyapatite crystals in the walls of blood vessels. MGP is also expressed in kidney and may inhibit the formation of kidney stones, which mainly consist of another crystalline phase, calcium oxalate monohydrate. To determine the mechanism by which MGP prevents soft-tissue calcification, we have synthesized peptides corresponding to the phosphorylated and γ-carboxylated sequences of human MGP in both post-translationally modified and non-modified forms. The effects of these peptides on hydroxyapatite formation and calcium oxalate crystallization were quantified using dynamic light scattering and scanning electron microscopy, respectively. Peptides YGlapS (MGP1-14: YγEpSHEpSMEpSYELNP), YEpS (YEpSHEpSMEpSYELNP), YGlaS (YγESHESMESYELNP) and SK-Gla (MGP43-56: SKPVHγELNRγEACDD) inhibited formation of hydroxyapatite in order of potency YGlapS > YEpS > YGlaS > SK-Gla. The effects of YGlapS, YEpS and YGlaS on hydroxyapatite formation were on both crystal nucleation and growth; the effect of SK-Gla was on nucleation. YGlapS and YEpS significantly inhibited the growth of calcium oxalate monohydrate crystals, while simultaneously promoting the formation of calcium oxalate dihydrate. The effects of these phosphopeptides on calcium oxalate monohydrate formation were on growth of crystals rather than nucleation. We have shown that the use of dynamic light scattering allows inhibitors of hydroxyapatite nucleation and growth to be distinguished. We have also demonstrated for the first time that MGP peptides inhibit the formation of calcium oxalate monohydrate. Based on the latter finding, we propose that MGP function not only to prevent blood-vessel calcification but also to inhibit stone formation in kidney.     

Wound-induced changes in the palatability of Betula pubescens and B. pendula

Summary Leaves of Betula were damaged artificially in April, June and August 1982. Palatability of damaged and adjacent undamaged leaves was assessed against controls in bioassays using the polyphagous Lepidoptera Spodoptera littoralis and Orgyia antiqua. Assessments were carried out at intervals from six hours to five months following each damage date. Palatability (relative proportions of leaves consumed) was significantly lower than controls in damaged and adjacent leaves after six hours and remained detectable for up to two months but this was less clear in the June-damaged samples and undetectable in the August group. Adjacent leaves were significantly affected whether distal or proximal to the damaged leaves. Marked and significant changes occurred in levels of soluble tannins in the damaged and adjacent leaves but the relationship between crude tannin levels and changed palatability was not simple cause and effect. No significant effects of damage on aphid (Euceraphis punctipennis) reproduction could be detected among birches in a growth room experiment in which half the trees were artificially damaged and half were controls. The results are discussed in the light of earlier work on induced defence in birch and five areas of significant new information represented by the results in this paper are identified.Spodoptera was reared under M.A.F.F. licence PHF 121/57     

Towards a classification of the environment and the community of Quercus robur

Abstract. The environment of the oak Quercus robur is precisely classified using a mathematical definition of the environment of a plant previously developed by the senior author. The definition is explained in words and a minimum of symbolism is used. The inclusion of each object in the environment of the oak is justified by a semi-formalized sentence, fully translated into ordinary English at the first usage. A diagram known as an ‘envirogram’, originally developed for the animal environment, is described. It presents the classification of the environment of a specific organism in simple graphic form. Two envirograms are given, for acorn and mature oak tree. These are the first plant envirograms to be constructed. A simplified community in a small habitat containing oaks and other organisms is described. It is fully analysed using a minimum of symbolism and classified as being of second order. The method gives mathematical precision to the notion that living organisms in a habitat are functionally related and it provides a modus operandi for the analysis of such a community.