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。     

香樟叶肉含晶细胞季节变化研究

为探讨香樟(Cinnamomum camphora)叶肉含晶细胞超微结构的季节变化,阐明香樟叶肉中草酸钙晶体在春夏秋冬的变化规律。该研究以多年生香樟(C. camphora)叶片为材料,分别于春夏秋冬四个季节露地取样,制作超薄切片,用透射电子显微镜(TEM)观察叶肉含晶细胞超微结构的变化。结果表明:春季时香樟叶肉中只有少数细胞有草酸钙晶体,数量较少,晶体结构多为柱状晶、方晶; 夏季时香樟叶肉细胞中随机分布于液泡的草酸钙晶体明显比春季的数量多、体积大、形态丰富,晶体多为柱状晶、方晶、针晶、簇晶; 秋季时香樟叶肉细胞草酸钙晶体和夏季的类似,数量较多,形态多样,以方晶和柱状晶针晶为主,伴有晶簇; 冬季时香樟叶肉含晶细胞晶体形态为柱状晶、方晶、针晶,数量比夏季和秋季的数量略有减少。该研究结果表明在一年四季中香樟叶肉细胞液泡中均有草酸钙晶体结构存在。     

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.     

植物教学试验材料集锦

观察植物细胞后含物针晶体,通常用芋叶柄作材料。在找不到芋叶柄的情况下,笔者对100多种野生和栽培植物进行了解剖观察,发现紫茉莉(Mirabilisjalapa)的茎、叶柄、叶片均可替代芋叶柄作观察材料。     

红豆草中含晶细胞的形态学研究

红豆草（Ｏｎｏｂｒｙｃｈｉｃｖｉｃｉａｅｆｏｌｉａｓｃｏｐ．）植株的所有器官中都分布有含晶细胞,其结晶的类型主要为棱晶,此外还有砂晶。在营养器官中,含棱晶的细胞主要分布在维管组织之中或外围。横切面上,棱晶则几至几十块纵列成行存在,且常伴生于韧皮纤维旁,但每块棱晶各有一分室隔开;在茎的表皮下偶有与大型粘液细胞伴生的砂晶。花萼的表皮中偶有棱晶,花瓣表皮及雄蕊药隔中有砂晶;子房壁内表皮下一层细胞逐渐发育成含棱晶的连续细胞,同时子房维管组织中也形成大量棱晶。分析表明,结晶成分为草酸钙。     

五种C4荒漠植物光合器官中含晶细胞的比较分析

为了探讨荒漠植物适应干旱环境的机理,选择光合器官发生很大变化的5种C4荒漠植物进行了解剖结构的对比研究。结果表明,这5种植物中含晶细胞的数量、大小、形态和分布位置等存在差异。白梭梭（Haloxylon persicum）和梭梭（H.ammodendron）的同化枝普遍具有含晶细胞;沙拐枣（Calligonum mongolicum）的含晶细胞很少,一般只分布在贮水组织或靠近栅栏组织处;木本猪毛菜（Salsola arbuscula）的含晶细胞也不多,主要分布在栅栏组织和表皮细胞之间;猪毛菜（S.collina）的含晶细胞更少,仅在贮水组织中偶尔可见晶簇。比较梭梭、白梭梭和沙拐枣同化枝不同部位的解剖结构发现,梭梭同化枝基部含晶细胞最多,中部次之,顶部最少;白梭梭同化枝项部的含晶细胞数量较多,中部及基部较少;沙拐枣同化枝顶部与基部的粘液细胞较多,中部较少,基部几乎没有栅栏组织,而其维管组织较为发达。综合晶体的酸碱溶解性及硝酸银组化分析结果,并参照能谱仪的分析结果得知,梭梭、白梭梭、沙拐枣和木本猪毛菜的叶片或同化枝中所含晶体的主要成分为草酸钙。通过比较解剖结构发现,梭梭和白梭梭的同化枝中含晶细胞最多,其它3种植物的同化器官中含晶细胞较少,而沙拐枣同化枝中有粘液细胞存在。     

五种C4荒漠植物光合器官中含晶细胞的比较分析

 为了探讨荒漠植物适应干旱环境的机理, 选择光合器官发生很大变化的5种C₄荒漠植物进行了解剖结构的对比研究。结果表明, 这5种 植物中含晶细胞的数量、大小、形态和分布位置等存在差异。白梭梭(Haloxylon persicum)和梭梭(H. ammodendron)的同化枝普遍具有含晶细 胞; 沙拐枣(Calligonum mongolicum)的含晶细胞很少, 一般只分布在贮水组织或靠近栅栏组织处; 木本猪毛菜(Salsola arbuscula)的含晶细 胞也不多, 主要分布在栅栏组织和表皮细胞之间; 猪毛菜(S. collina)的含晶细胞更少, 仅在贮水组织中偶尔可见晶簇。比较梭梭、白梭梭和 沙拐枣同化枝不同部位的解剖结构发现, 梭梭同化枝基部含晶细胞最多, 中部次之, 顶部最少; 白梭梭同化枝顶部的含晶细胞数量较多, 中部 及基部较少; 沙拐枣同化枝顶部与基部的粘液细胞较多, 中部较少, 基部几乎没有栅栏组织, 而其维管组织较为发达。综合晶体的酸碱溶解性 及硝酸银组化分析结果, 并参照能谱仪的分析结果得知, 梭梭、白梭梭、沙拐枣和木本猪毛菜的叶片或同化枝中所含晶体的主要成分为草酸钙 。通过比较解剖结构发现, 梭梭和白梭梭的同化枝中含晶细胞最多, 其它3种植物的同化器官中含晶细胞较少, 而沙拐枣同化枝中有粘液细胞存 在。     

植物晶体的形态结构、生物功能及形成机制研究进展

晶体是植物体内产生的一种具有特殊形态结构与生理功能的代谢物,其分布广泛,已在500多种植物中发现有晶体的存在。晶体形态多样,有针晶、柱晶、棱晶、砂晶、簇晶等;类型丰富,有草酸钙晶体、钟乳体、硅质体、硫酸钙晶体及其它类型的晶体;功能特殊,具有钙调节、植物保护和防御、重金属解毒、离子平衡、缓解逆境胁迫及其它多种生物功能。晶体的形成涉及钙离子的体外吸收和体内转运,草酸的生物合成,以及钙离子和草酸的耦合过程;晶体的生长发育涉及液泡、晶异细胞的调控及与其它细胞结构的相互协作。对晶体的研究进行综述,以期为晶体的进一步研究提供基础资料。     

草酸钙晶体与药材植物的鉴别

草酸钙结晶存在于很多植物体中,它是植物生长过程中的代谢产物,在一般显微镜下就能观察到,其形态有方形、针状、多棱状集合体、砂粒状、柱状,分别称方晶、针晶、簇晶、砂晶、柱晶。药材植物种类繁多,已入药的达6千余种。其所含草酸钙结晶的形状、大小、多少、分布疏     

中国假鹰爪属和皂帽花属植物叶的形态结构及其分类学意义

利用扫描电镜技术、叶片离析法和石蜡切片法研究了假鹰爪属Desmos 4种植物和皂帽花属Dasy-maschalon 3种植物叶片的形态结构。结果表明：假鹰爪属植物叶片近轴面表皮具大型球状含晶簇细胞和不含晶簇的表皮细胞两种类型,远轴面表皮细胞均具一较小的晶簇;叶肉组织明显分化为栅栏组织细胞和海绵组织细胞,油细胞分布于第2层的栅栏组织和海绵组织内,单位毫米叶宽油细胞数为4～6个;主脉维管组织被薄壁细胞分隔成束状。皂帽花属植物叶片近轴面表皮细胞形状相同,均具一晶簇,远轴面表皮细胞的晶簇和近轴面表皮细胞的晶簇相似;靠近上、下表皮的叶肉组织均分化为栅栏组织细胞,在两层栅栏组织细胞之间分化为一至几层海绵组织细胞,油细胞分布于海绵组织内,单位毫米叶宽油细胞数为2～3个;主脉维管组织形成连续的环状。由此可见两属叶的结构具有明显的差异,因而支持假鹰爪属和皂帽花属为两个独立属的观点。     

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.     

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.     

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.     

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     

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.     

DISTRIBUTION OF CALCIUM OXALATE CRYSTAL IDIOBLASTS IN CORMS OF TARO (COLOCASIA ESCULENTA)

The morphology and distribution of intracellular crystals of calcium oxalate in taro (Colocasia esculenta) was studied by light microscopy. The modified Pizzolato (AgNO₃-H₂O₂) method was used to localize crystals in cleared corm cross sections. Crystals of two forms were found: druses and raphides. The numbers and density of the crystals in corms increase rapidly in early development, then level off, and eventually decrease in older and larger corms. An especially high concentration of druses was observed 2-3 mm from the exterior edge of many corms. This corresponds to a ring of vascular tissue which circumscribes the corm at approximately the same distance from the surface. Observations suggest that the development of these highly specialized cells and the formation of calcium oxalate crystals is a dynamic process.     

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.