虎掌（天南星科）中草酸钙晶体的形态和分布

在光学显微镜下对虎掌（Pinellia pedatisecta）营养器官和繁殖器官中晶体的类型和分布进行了观察和分析,探讨晶体的功能与作用机制。结果表明：（1）虎掌各个器官中都发现有晶体,且晶体类型有针晶、簇晶、砂晶和柱晶4种形态,其中针晶最为常见。（2）虎掌叶中的晶体大多以针晶状分布在叶片上表皮下的叶肉中,少数分布在叶下表皮下的叶肉中,其次砂晶和星芒状簇晶也在叶中较常见,叶中也有少量的柱晶。（3）虎掌的块茎中分布有大量的针晶束,在输导组织附近还有一些大的簇晶;虎掌的不定根中分布有不整齐的针晶和排列不规则的针晶束以及少量大的簇晶。（4）虎掌的佛焰苞中分布有针晶、簇晶和砂晶,且在佛焰苞中的针晶主要分布于上、下表皮之下的叶肉中,砂晶多分布在佛焰苞的上、下表皮上。（5）虎掌的花药壁中分布有针晶束,其方向和花药壁表面垂直,而花粉囊中只有小的簇晶。（6）虎掌的果皮和种皮上分布有大量的针晶。根据晶体在酸中的溶解性,虎掌体内所有晶体的化学成分都为草酸钙。研究认为,虎掌各个器官中的各种草酸钙晶体对于保护虎掌免受食草动物取食具有重要的作用。     

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.     

A study on calcium oxalate crystals in <Emphasis Type="Italic">Tinantia anomala</Emphasis> (Commelinaceae) with special reference to ultrastructural changes during anther development

Calcium oxalate (CaOx) crystals in higher plants occur in five forms: raphides, styloids, prisms, druses, and crystal sand. CaOx crystals are formed in almost all tissues in intravacuolar crystal chambers. However, the mechanism of crystallization and the role of CaOx crystals have not been clearly explained. The aim of this study was to explore the occurrence and location of CaOx crystals in organs of Tinantia anomala (Torr.) C.B. Clarke (Commelinaceae) with special attention to ultrastructural changes in the quantity of tapetal raphides during microsporogenesis. We observed various parts of the plant, that is, stems, leaves, sepals, petals, anthers, staminal trichomes and stigmatic papillae and identified CaOx crystals in all parts except staminal trichomes and stigmatic papillae in Tinantia anomala. Three morphological forms: styloids, raphides and prisms were found in different amounts in different parts of the plant. Furthermore, in this species, we identified tapetal raphides in anthers. The number of tapetal raphides changed during microsporogenesis. At the beginning of meiosis, the biosynthesis of raphides proceeded intensively in the provacuoles. These organelles were formed from the endoplasmic reticulum system. In the tetrad stage, we observed vacuoles with needle-shaped raphides (type I) always localised in the centre of the organelle. When the amoeboid tapetum was degenerating, vacuoles also began to fade. We observed a small number of raphides in the stage of mature pollen grains.     

New and unusual forms of calcium oxalate raphide crystals in the plant kingdom

Calcium oxalate crystals in higher plants occur in five major forms namely raphides, styloids, prisms, druses and crystal sand. The form, shape and occurrence of calcium oxalate crystals in plants are species- and tissue-specific, hence the presence or absence of a particular type of crystal can be used as a taxonomic character. So far, four different types of needle-like raphide crystals have been reported in plants. The present work describes two new and unusual forms of raphide crystals from the tubers of Dioscorea polystachya—six-sided needles with pointed ends (Type V) and four-sided needles with beveled ends (Type VI). Both of these new types of needles are distinct from the other four types by each having a surrounding membrane that envelopes a bundle of 10–20 closely packed thin crystalline sheets. The previously known four types of needles have solid or homogenous crystalline material, surrounded by a membrane or lamellate sheath called a crystal chamber. Only the Type VI crystals have beveled ends and the needles of the other five types have pointed ends.     

On the presence of extracellular calcium oxalate crystals on the inflorescences of Araceae

This study presents a survey of the species of the Araceae where extracellular production of calcium oxalate crystals has been observed and discusses the patterns of production of the crystals in different genera. For all Araceae studied using SEM, the oxalate crystals exuding on the epidermal surface correspond to extended aggregate/druses or crystal sand and the oxalate crystals mixed with pollen correspond to raphides or styloids (prismatic crystals). The type of crystals associated with pollen varies among genera. However, the presence of crystals associated with pollen is a specific rather than a generic characteristic. Our results show that the presence of raphides mixed with pollen seems to be a widespread phenomenon in the aroid family.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 181–190.     

Cellular ultrastructure and crystal development in Amorphophallus (Araceae)

Background and Aims: Species of Araceae accumulate calcium oxalate in the form ofcharacteristically grooved needle-shaped raphide crystals andmulti-crystal druses. This study focuses on the distributionand development of raphides and druses during leaf growth inten species of Amorphophallus (Araceae) in order to determinethe crystal macropatterns and the underlying ultrastructuralfeatures associated with formation of the unusual raphide groove. Methods: Transmission electron microscopy (TEM), scanning electron microscopy(SEM) and both bright-field and polarized-light microscopy wereused to study a range of developmental stages. Key Results: Raphide crystals are initiated very early in plant development.They are consistently present in most species and have a fairlyuniform distribution within mature tissues. Individual raphidesmay be formed by calcium oxalate deposition within individualcrystal chambers in the vacuole of an idioblast. Druse crystalsform later in the true leaves, and are absent from some species.Distribution of druses within leaves is more variable. Drusesinitially develop at leaf tips and then increase basipetallyas the leaf ages. Druse development may also be initiated incrystal chambers. Conclusions: The unusual grooved raphides in Amorphophallus species probablyresult from an unusual crystal chamber morphology. There aremultiple systems of transport and biomineralization of calciuminto the vacuole of the idioblast. Differences between raphideand druse idioblasts indicate different levels of cellular regulation.The relatively early development of raphides provides a defensivefunction in soft, growing tissues, and restricts build-up ofdangerously high levels of calcium in tissues that lack theability to adequately regulate calcium. The later developmentof druses could be primarily for calcium sequestration.     

A comparison of leaf crystal macropatterns in the two sister genera Piper and Peperomia (Piperaceae)

? Premise of the study: This is the first large-scale study comparing leaf crystal macropatterns of the species-rich sister genera Piper and Peperomia. It focuses on identifying types of calcium oxalate crystals and their macropatterns in leaves of both genera. The Piper results are placed in a phylogenetic context to show evolutionary patterns. This information will expand knowledge about crystals and provide specific examples to help study their form and function. One example is the first-time observation of Piper crystal sand tumbling in chlorenchyma vacuoles. ? Methods: Herbarium and fresh leaves were cleared of cytoplasmic content and examined with polarizing microscopy to identify types of crystals and their macropatterns. Selected hydrated herbarium and fresh leaf punches were processed for scanning electron microscopy and x-ray elemental analysis. Vibratome sections of living Piper and Peperomia leaves were observed for anatomical features and crystal movement. ? Key results: Both genera have different leaf anatomies. Piper displays four crystal types in chlorenchyma-crystal sand, raphides, styloids, and druses, whereas Peperomia displays three types-druses, raphides, and prisms. Because of different leaf anatomies and crystal types between the genera, macropatterns are completely different. Crystal macropattern evolution in both is characterized by increasing complexity, and both may use their crystals for light gathering and reflection for efficient photosynthesis under low-intensity light environments. ? Conclusions: Both genera have different leaf anatomies, types of crystals and crystal macropatterns. Based on Piper crystals associated with photosynthetic tissues and low-intensity light, further study of their function and association with surrounding chloroplasts is warranted, especially active crystal movement.     

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     

Morphologies and elemental compositions of calcium crystals in phyllodes and branchlets of Acacia robeorum (Leguminosae: Mimosoideae)

Background and Aims

Formation of calcium oxalate crystals is common in the plant kingdom, but biogenic formation of calcium sulfate crystals in plants is rare. We investigated the morphologies and elemental compositions of crystals found in phyllodes and branchlets of Acacia robeorum, a desert shrub of north-western Australia.

Methods

Morphologies of crystals in phyllodes and branchlets of A. robeorum were studied using scanning electron microscopy (SEM), and elemental compositions of the crystals were identified by energy-dispersive X-ray spectroscopy. Distributional patterns of the crystals were studied using optical microscopy together with SEM.

Key Results

According to the elemental compositions, the crystals were classified into three groups: (1) calcium oxalate; (2) calcium sulfate, which is a possible mixture of calcium sulfate and calcium oxalate with calcium sulfate being the major component; and (3) calcium sulfate · magnesium oxalate, presumably mixtures of calcium sulfate, calcium oxalate, magnesium oxalate and silica. The crystals were of various morphologies, including prisms, raphides, styloids, druses, crystal sand, spheres and clusters. Both calcium oxalate and calcium sulfate crystals were observed in almost all tissues, including mesophyll, parenchyma, sclerenchyma (fibre cells), pith, pith ray and cortex; calcium sulfate · magnesium oxalate crystals were only found in mesophyll and parenchyma cells in phyllodes.

Conclusions

The formation of most crystals was biologically induced, as confirmed by studying the crystals formed in the phyllodes from seedlings grown in a glasshouse. The crystals may have functions in removing excess calcium, magnesium and sulfur, protecting the plants against herbivory, and detoxifying aluminium and heavy metals.     

OCCURRENCE,TYPE, AND LOCATION OF CALCIUM OXALATE CRYSTALS IN LEAVES AND STEMS OF 16 SPECIES OF POISONOUS PLANTS

Crystals in 16 species of poisonous plants growing naturally in Saudi Arabia were studied with light microscopy. Three types of crystals were observed: druses, prismatics, and crystal sand. Raphides and styloids were not observed in any of the species studied. Druses occur more frequently in the leaf midrib and in the cortex and pith of the stem. In contrast, crystal sand and prismatic crystals are rare and occur in the leaf, intercostal lamina, and in the vascular tissues. The preliminary results show the absence of the three types of calcium oxalate crystals in the stem and leaf of seven species: Ammi majus L., Anagallis arvensis L., Calotropis procera Ait., Citrullus colocynthis (L.) Schard, Euphorbia peplis L., Hyoscyamus muticus L., and Solarium nigrum L., and the presence of druses, prismatic crystals, and crystal sand either in the leaf and stem or in the leaves or stems of nine species: Anabasis articulata (Forssk.) Moq. in DC., Chenopodium album L., Convolvulus arvensis L., Datura stramonium L., Nerium oleander L., Ricinus communis L., Rumex nervosus Vahl., Pergularia tomentosa L., and Withania somnifera (L.) Dun. in DC. These observations indicate that there is no apparent relationship between the distribution of calcium oxalate crystals and the toxic organs of the plants, and supports the view that the presence of calcium oxalate crystals may not be related to plant toxicity.     

MORPHOLOGY AND DISTRIBUTION OF COLLETERS AND CRYSTALS IN RELATION TO THE TAXONOMY AND BACTERIAL LEAF NODULE SYMBIOSIS OF PSYCHOTRIA (RUBIACEAE)

Earlier investigators established that a finger-like colleter with elongate axial cells and a palisade epidermis is the standard type in the Rubiaceae. This type, with some variation, also prevails in Psychotria, based on a worldwide anatomical survey of vegetative buds from herbarium specimens of 296 species (about 50 % of total). It is virtually the only type found outside of continental Africa. Among African species, it is most common in subgenus Psychotria, with mostly nodule-free species. In subgenus Tetramerae, with only leaf-nodulated species, there is a strong tendency toward brushlike and dendroid colleters in which epidermal cells are extremely elongate and separated from each other. It is speculated that this change in colleter morphology associated with presence of nodule bacteria may be correlated with a change in secretion product more suitable for support of bacteria. Three morphological forms of crystal occur: raphides, styloids, clustered crystals. They may occur singly or in combination. Several patterns and trends were noted in crystal distribution that could be of taxonomic significance.     

Crystallochemical characterization of calcium oxalate crystals isolated from seed coats of Phaseolus vulgaris and leaves of Vitis vinifera

Calcium oxalate crystals are a major biomineralization product in higher plants. Their biological function and use are not well understood. In this work, we focus on the isolation and crystallochemical characterization of calcium oxalate crystals from seed coats of Phaseolus vulgaris (prisms) and leaves of Vitis vinifera (raphides and druses) using ultrastructural methods. A proposal based on crystal growth theory was used for explaining the existence of different morphologies shown by these crystals grown inside specialized cells in plants.     

Subepidermal idioblasts and crystal macropattern in leaves of Ticodendron (Ticodendraceae)

Previously unknown leaf anatomy and foliar crystal macropattern are described for Ticodendron incognitum Gómez-Laurito and Gómez P. (monotypic eudicot family Ticodendraceae of a Fagales subclade with Betulaceae and Casuarinaceae). Leaf samples of five herbarium specimens were rehydrated, bleached, dehydrated to 100% ethanol, then xylol, mounted in Permount and viewed using polarizing microscopy. Large adaxial and abaxial hypodermal idioblasts occur. Numerous small druses populate palisade mesophyll, and fewer, larger druses populate the spongy mesophyll; this is the opposite of druse distribution in Fagaceae. Druses dominate major veins, many with visible cores, and some prisms occur. Minor veins exhibit isolated groups of 1–8 druses and rare prisms, but most terminal veins lack crystals. Many druses are misshapen or with epitactic crystals; several unusual variants of druses and prisms are common. Hypodermal idioblasts are an apomorphy for Ticodendraceae, but oil and resin cells occur in Myricaceae and Rhoipteleaceae of Fagales. Crystal forms and distribution differ from known Fagalean macropatterns.     

Calcium oxalate crystal types and trends in their distribution patterns in leaves ofPrunus (Rosaceae: Prunoideae)

Calcium oxalate crystal types and distribution within leaves ofPrunus sensu lato (Rosaceae; Prunoideae) were surveyed from mostly herbarium specimens (196 specimens of 131 species of all five subgenera usually recognized). Rehydrated samples were bleached, mounted unstained, and viewed microscopically between crossed polarizers. Six patterns were recognized based on crystal type and relative distribution around veins and in mesophyll. Druses predominate in four subgenera, but prismatics are most common in subgenus Padus. Prunophora and Amygdalus, considered to be the most advanced subgenera, have virtually only druses, which are almost always associated with veins. Cerasus and Laurocerasus, intermediate subgenera, have the greatest diversity of patterns, but few species with prismatics. A trend is evident from mostly mesophyll prismatics in Padus to fewer prismatics and more druses of mixed distribution in Laurocerasus and Cerasus, to mostly druses restricted to veins in Amygdalus and Prunophora.     

Twinned Raphides of Calcium Oxalate in Grape (Vitis): Implications for Crystal Stability and Function

Among the higher plants that accumulate crystalline calcium oxalate, many taxa characteristically produce raphides, or needle-shaped crystals. Substantial evidence has accumulated indicating that raphides function in plant defenses against herbivory and that their acicular shape is a critical component in proposed mechanisms for these defenses. Previous observations have shown that raphides in members of the Vitaceae are twinned crystals. In this study, the fine structure of raphides in Vitis was examined in order to determine the nature of twinning. Rotation of isolated raphides under cross-polarized light revealed extinction patterns that indicated that raphides are twinned along their length. In cross sections of raphides, the twin plane extends across the raphides, parallel to their surfaces. The dissolution patterns observed in etched crystals indicate that the type of twinning is rotational. Parallels in other biomineralization systems indicate that the rotational nature of the twinning may increase mechanical strength. In addition, because twinning may affect crystal growth or enhance stability and persistence of crystals, it could be an important factor in allowing plant cells to produce the raphide morphology.     

Mature Raphid and Raphid Idioblast Structure in Plants of the Edible Aroid Genera Colocasia, Alocasia, and Xanthosoma

Mature raphid idioblasts examined in this study appear to consistof a bundle of raphid crystals contained within a polysaccharidematrix. The cytoplasm consists of a thin parietal layer withfew discernible organelles. These cells appear to be true idioblasts,and no intercellular connections were observed between thesecells and adjacent parenchyma cells. Dissolution of the middlelamella occurs in Colocasia and to some extent in Xanthosoma.The mechanism of crystal release in the five species studiedis the same, e.g. a swelling of a polysaccharide material whichbreaks the idioblast wall and forces the release of the raphides.In Colocasia this results in a forceful ejection with releaseof a relatively few number of crystals at any one time. Xanthosomaand Alocasia do not exhibit a forceful ejection of their crystals,but a less forceful release of a crystal mass which then disassociatesto free the individual crystals. The raphides differ in structureand size, however, they have three structural features in common.First, the crystals have two distinct points, one tapering toan elongate point, the other abruptly pointed. Second, the crystalshave surface barbs with tips oriented away from the taperingpoint. And third, deep grooves are present along the lengthof the crystals. The possible relationship between raphid structureand the acrid nature of the idioblasts is discussed.     

Capture Rates of Male Euglossine Bees across a Human Intervention Gradient, Chocó Region, Colombia1

Euglossine bees are important pollinators of lowland Neotropical forests. Compared to disturbed habitats, undisturbed ones have been previously characterized by higher abundance and diversity of euglossine bees. Most past studies have relied on chemically baiting male bees at single sites within habitats. Over a two‐year period, we employed a repeated‐measures design in which we sampled bees at multiple sites within three different habitat types, reflecting a mosaic of human disturbance (farm, secondary forest, and old logged forest). After 22 monthly samples, a total of 2008 male bees were captured, representing 31 species in five genera: 1156 at the farm (57.6%, 21 spp.), 505 in the secondary forest (25.1%, 27 spp.), and 347 in the old logged forest (17.2%, 21 spp.). Eighty‐one percent of the bees captured belonged to the five most abundant species: Eulaema cingulata, El. chocoana, Euglossa hansoni, Eg. ignita, and Eg. imperialis. These species differed significantly in capture frequencies among habitats. Eulaema cingulata, El. chocoana, and Eg. ignita were captured most frequently at the farm, while Eg. imperialis was most abundant in the secondary forest. In contrast, Eg. hansoni, the sole short‐tongued species among the five, was equally abundant in the two forest habitats but occurred rarely on the farm. Additionally, habitats differed in bee composition. The high capture rates for long‐proboscis species at the farm may have been due to their ability to extract nectar from flowers with long floral tubes, which probably occurred at a greater density on the farmed land than in the adjacent forests.     

Diversity and distribution of idioblasts producing calcium oxalate crystals in Dieffenbachia seguine (Araceae)

Although cells that synthesize crystals are known throughout the plant kingdom, their functional significance is still unknown. Mechanical support, mineral balance, waste sequestration, and protection against herbivores have all been proposed as crystal functions. To seek clues to their role(s), I systematically examined all organs except fruit of Dieffenbachia seguine (Araceae) for crystals. Crystals were found in nearly every organ. Raphides (long, slim, pointed crystals) were most common, but druses (crystal aggregates) and prisms were also found. Raphides varied in size by a factor of 10 and also in organization from tightly bundled to loosely organized. Biforines, a type of cell capable of expelling raphides, or biforine-like cells, were found in nearly all organs, but especially in leaves, spathes, and anthers. Different organs had different crystal complements, and characteristic crystals were found at specific locations, such as among pollen, along the undersides of leaf veins, and at root branch points. All crystals appeared to be composed of calcium oxalate, based on acid solubility. Possible roles of the crystals are discussed in light of these findings.     

Styloid crystals in Claoxylon (Euphorbiaceae) and allies (Claoxylinae) with notes on leaf anatomy

Claoxylon and Micrococca are the only Euphorbiaceae genera that have rough dried leaves (fresh ones are smooth) because of protruding styloid (needle-like) crystals more or less perpendicular to the leaf surface, which perforate the epidermis and cuticle. A broad leaf anatomical study of the subtribes Claoxylinae, the monogeneric Lobaniliinae, and Mercurialis of the Mercurialinae (95 of a possible 235 species in all six genera) showed that styloids are present in Claoxylon , Discoclaoxylon , Erythrococca , Lobanilia , and Micrococca , and lacking in Claoxylopsis and Mercurialis . Contrary to Claoxylon , the dried leaves of Discoclaoxylon , Erythrococca , Lobanilia , and Micrococca are not rough, because the styloids do not perforate the epidermis during drying and therefore herbarium leaves generally remain smooth. The presence of styloids supports a clade in a recent molecular phylogenetic study that unites subtribes Claoxylinae and Lobaniliinae as Claoxylinae s.l. Mercurialis (no styloids) is sister to all other taxa (with styloids) in the monophyletic Claoxylinae s.l. The styloids form a synapomorphy for a monophyletic part of the Claoxylinae ( Claoxylon , Discoclaoxylon , Erythrococca , Lobanilia , and Micrococca ). Other leaf anatomical notes are provided, together with an overview of the occurrence of styloids, stomata, and druse crystals for most species in the Claoxylinae. The indumentum ranges from (virtually) absent to a sparse or dense tomentum of straight and thick- or thin-walled unicellular hairs (most common), curly hairs, or two-armed hairs ('Malpighiaceous hairs'). The last two hair types probably form diagnostic characters for species groups within the genus Claoxylon .  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 445–457.     

Crystal macropatterns in leaves of Fagaceae and Nothofagaceae: a comparative study

Summary Crystal macropatterns in Fagaceae and Nothofagaceae were examined from cleared herbarium leaves (eight genera, 122 spp.) by polarizing microscopy. Prisms and druses dominate, but previously undescribed intermediate forms occur in 25 species of Fagaceae. Sixty-two species had only prisms associated with vein orders 1–4, but smallest orders 5 and 6 had few or no crystals. In mesophyll, 98 species had small druses in spongy parenchyma and larger but fewer druses in palisade parenchyma. Subfamily Fagoideae conformed closely to this macropattern, Castaneoideae less so. Six Castaneoideae species lacked vein crystals. Two Fagoideae species and seven Nothofagus species lacked mesophyll crystals. Druses with prominent cores occur throughout Fagaceae but none were seen in Nothofagaceae. Tabular presentation of results shows significant although overlapping trends from Fagoideae to Castaneoideae to Nothofagaceae, with the latter taxon deviating most from Fagaceae.