Glandular hairs of Sigesbeckia jorullensis Kunth (Asteraceae): morphology,histochemistry and composition of essential oil

Long-stalked glandular hairs of outer and inner involucral bracts of Sigesbeckia jorullensis, which are important for epizoic fruit propagation, were investigated using light and scanning electron microscopy. The essential oil secreted by the hairs was analysed by chromatographic methods including gas chromatography/mass spectrometry and with a laser microprobe mass analyser. The glandular hairs consisted of a large multicellular stalk and a multicellular secreting head. The apical layer of glandular head cells was characterized by leucoplasts and calcium oxalate crystals. Below the apical cells there were up to six layers of cells containing many chloroplasts around the nucleus and surrounded by vacuoles filled with flavonoids and tannins. The essential oil originating in the head cells was secreted into the subcuticular space and may be liberated by rupture of the cuticle. It was mainly composed of sesqui- and diterpenes, with the sesquiterpene hydrocarbon germacrene-D as the main component. Monoterpenes, n-alkanes and their derivatives as well as flavonoid aglycones were also detected. The stickiness of the essential oil is probably associated with the high content of oxygenated sesqui- and diterpenes. In addition to long-stalked trichomes, small biseriate trichomes occurred, secreting small quantities of essential oil into a subcuticular space.     

The caddisfly Ceraclea fulva and the freshwater sponge Ephydatia fluviatilis: a successful relationship

The association between the aquatic phases of the caddisfly Ceraclea fulva (Trichoptera, Leptoceridae) and the freshwater sponge Ephydatia fluviatilis (Porifera, Spongillidae) has been investigated by means of scanning and transmission electron microscopy (SEM, TEM). Ceraclea fulva habitually feeds on sponges and builds its case by using the siliceous spicules of the sponge, which are arranged side by side, inter-crossed, cemented with silk, and organised in layers. In the newly hatched larva, the case is strengthened exclusively by cemented siliceous spicules, while during growth, the insect adds sponge fragments to it. The fine organisation of the sponge tissues growing on the case proves that the sponge is functional. Inter-spaced, small protrusions, derived from the outermost compact silk layer, form a series of "bridges" enhancing case/sponge adhesion. Tube-case shape varies according to the aquatic developmental phase of the insect: in the mature larva and pupa, this shelter carries larger sponge fragments dorsally. The caddisfly acts as carrier of the sponge, thus facilitating its dispersal and the colonisation of new habitats. This justifies regarding this association as a successful mutualistic relationship, and not as a unilateral parasitic behaviour on the part of the insect.     

Rumen ciliated protozoan fauna of the yak (Bos grunniens) in China with the description of Entodinium monuo n. sp

Rumen ciliate species composition was surveyed in domestic yaks kept in Tibet, Sichuan, and Inner Mongolia, China. Twelve genera including 36 species with 18 formae were identified. The species compositions were slightly different among the three areas: yaks in Tibet had the simplest fauna, in contrast, the fauna of yaks in Inner Mongolia were the most abundant and similar to those found in the cattle kept in the same area. This suggests that the rumen ciliate composition of yaks is affected by that of cattle kept together or in proximity. A new species belonging to the genus Entodinium, Entodinium monuo n. sp., was recognized from the yaks in all areas. This new species was common in the yaks but was not detected in the cattle fed near yaks in Inner Mongolia. There was a similar generic ciliate composition in yaks kept in respective areas. Entodinium was the most predominate ciliate (51.9-61.0%) with total ciliate densities estimated as 10(5)/ml per yak.     

Effect of lanthanum on ion absorption in cucumber seedling leaves

Scanning electron microscope and energy-dispersive X-ray analysis were used to study the tissular distributions of elements Na, Mg, Cl, K, Ca, Mn, and Fe in leaves of cucumber seedlings in the absence or presence of La³⁺. The results showed that the atomic percentages of Na, Mg, Cl, K, and Ca were basically reduced and those of Mn and Fe were increased in the presence of La³⁺; in addition, at 0.02 mM La³⁺, the reduced or increased degrees were higher than those at 2.0 mM La³⁺. The effects of La³⁺ on ion absorption were similar to those of Ca²⁺, suggesting that the rare earth element lanthanum affects the plant physiological mechanism by regulating the Ca²⁺ level in plant cell.     

杜鹃花属映山红亚属植物叶表皮显微形态特征及其分类学意义

为澄清映山红亚属(Rhododendron subg. Tsutsusi)内的系统关系问题,该研究选择杜鹃花属映山红亚属37种植物作为对象,其中29种为首次报道,通过扫描电镜观察其叶表皮显微特征。结果表明:(1)气孔器均为无规则型且均在远轴面。(2)根据叶片微形态特征将映山红亚属的种类分为杜鹃型(R. simisii-type)、岭南杜鹃型(R. mariae-type)、皋月杜鹃型(R. indicum-type)、崖壁杜鹃型(R. saxatile-type)及丁香杜鹃型(R. farrerae-type)5种类型。(3)杜鹃型植物的气孔器周边无或具间断的条形突起。(4)岭南杜鹃型植物的气孔器周围有多层条形突起环绕,保卫细胞两极不具T型加厚。(5)皋月杜鹃型植物的叶表皮保卫细胞两极具有T型加厚,与叶状苞亚属(Subg. Therorhodion)叶状苞杜鹃(R. redowskianum)的气孔器特征相似,推测其与叶状苞亚属具有一定的亲缘关系。(6)崖壁杜鹃型植物的叶表皮毛单一,多呈卷曲状,与其他类型有所不同且未见腺体。(7)丁香杜鹃型植物的叶表皮仅有腺体。(8)依据叶表皮微形态特征讨论了一些近缘种类的关系,如倾向于将背绒杜鹃(R. hypoblematosum)和千针叶杜鹃(R. polyraphidoideum)处理为独立的种,支持保留紫薇春(R. naamkwanense var. cryptonerve)作为南昆杜鹃(R. naamkwanense)的变种地位,不支持将腺花杜鹃(R. adenanthum)并入细瘦杜鹃(R. tenue)作异名处理等。该研究结果表明叶表皮显微特征在映山红亚属内物种划分上具有重要价值。     

Cypris morphology in the barnacles Ibla and Paralepas (Crustacea: Cirripedia Thoracica) implications for cirripede evolution

We used scanning electron microscopy (SEM) to describe cypris morphology in species of the barnacles Ibla and Paralepas, both of which are pivotal in understanding cirripede evolution. In Ibla, we also studied late naupliar stages with video and SEM. Special emphasis was put on the lattice organs, the antennules and the thorax and telson. In Paralepas we had settled specimens only and could therefore only investigate the carapace with the lattice organs. Cyprids of Ibla quadrivalvis and Paralepas dannevigi have five sets of lattice organs, grouped as two anterior and three posterior pairs. The organs are of the pore‐field type and the terminal pore is situated anteriorly in the first pair, just as in the Rhizocephala and the Thoracica. In Ibla the armament of antennular sensilla resembles that found in the Thoracica but differs from the Rhizocephala. The absence of setules on the A and B setae sited terminally on the fourth antennular segment is a similarity with the Acrothoracica. The attachment disc is angled rather than facing distally and is encircled by a low cuticular velum. The thoracopods have two‐segmented endopods and exopods as in the Thoracica, but the number, shape, and position of thoracopodal setae differ somewhat from other species of that superorder. Both Ibla and Paralepas cyprids have a deeply cleaved telson, but no independent abdominal part. In cypris morphology, Ibla and Paralepas show several synapomorphies with the clade comprising Rhizocephala and Thoracica and there are no specific apomorphies with either the Acrothoracica, the Rhizocephala or any particular subgroup within the Thoracica. This is in agreement with recent molecular evidence that Ibla (Ibliformes) is the sister taxon to all other Thoracica and the ibliforms therefore become the outgroup of choice for studying character evolution within the superorder. Paralepas, and other pedunculated barnacles without shell plates, are apparently not primitive but are secondarily evolved and nested within the Thoracica. J. Morphol., 2009. © 2008 Wiley‐Liss, Inc.     

Lateral organs in sedentary polychaetes (Annelida) – Ultrastructure and phylogenetic significance of an insufficiently known sense organ

Lateral organs are sense organs visible as densely ciliated pits or papillae between the noto‐ and the neuropodia in certain taxa of sedentary polychaetes. Ultrastructural studies in about 10 species of the following taxa Maldanidae, Opheliidae, Orbiniidae, Paraonidae, Magelonidae, Spionidae, Poecilochaetidae and Terebellidae have been designed to evaluate whether these organs are homologous among polychaetes. In spite of great external diversity, the investigations revealed an overall ultrastructural similarity. Differences between species investigated mainly concern the size of the organs as well as the number and arrangement of cells. The organs comprise supportive cells and uniciliated penetrative sensory cells. Their dendrites are closely arranged and thus their cilia may resemble multiciliated cells. There are two types of sensory cells: one type possesses no or mainly thin microvilli of which usually only a few reach the cuticular surface, and in the other type the cilium is consistently surrounded by 10 strong microvilli, which form a pore‐like opening in the cuticle. Further differences occur in the structure of the rootlet system. Basally, a retractor muscle attaches to the organ. The systematic significance of these organs within Annelida is discussed with respect to the conflicting phylogenetic hypotheses explaining the relationships of annelid taxa.     

ISOLATION OF A NON‐PHAGE‐LIKE LYTIC VIRUS INFECTING AUREOCOCCUS ANOPHAGEFFERENS1

We have been working to characterize viruses that infect the HAB‐forming pelagophyte Aureococcus anophagefferens Hargraves et Sieburth. Field samples were collected during brown‐tide events in 2002 and tested for the presence of lytic agents. Here, we describe a recently isolated, lytic virus‐like particle (VLP) that is morphologically similar to particles observed in thin sections of infected A. anophagefferens cells from natural samples. TEM and SEM have revealed VLPs consistent with the morphological characteristics of previously described Phycodnaviridae. Large icosahedral particles (～140 nm) of similar shape and morphology dominate cell lysates and are accompanied by smaller phage‐like particles and heterotrophic prokaryotes that appear to be incurable from our cultures. To determine which of these particles interacts with the Aureococcus cells, we preserved cultures during the early stage of infection so that SEM could be used to visualize those particles that attach to the surface of naïve cultures. SEM revealed that 63% of the large icosahedral‐shaped particles attached to A. anophagefferens cells after only 30 min of exposure, while no significant frequency of attachment to the alga was observed for the phage‐like particles. The results of these observations are in contrast to previous studies, where phage‐like particles were reported to infect cells. When considered in conjunction with field observations, the results suggest that this newly isolated virus represents the dominant virus‐morphotype associated with bloom collapse and termination.     

Photoluminescence properties of LiBaPO4:M3+ phosphor for near‐UV light‐emitting diode (M = Eu and Dy)

A novel phosphor LiBaPO₄ doped with rare earths Eu and Dy prepared by high temperature solid‐state reaction method is reported. The phosphors were characterized by X‐ray powder diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL). The emission and excitation spectra of these materials were measured at room temperature with a spectrofluorophotometer. The excitation spectra of LiBaPO₄:Eu³⁺ phosphor can be efficiently excited by 394 nm, which is matched well with the emission wavelength of near‐UV light‐emitting diode (LED) chip. PL properties of Eu³⁺‐doped LiBaPO₄ exhibited the characteristic red emission coming from ⁵D₀ → ⁷ F₁ (593 nm) and ⁵D₀ → ⁷ F₂ (617 nm) electronic transitions with color co‐ordinations of (0.680, 0.315). The results demonstrated that LiBaPO₄:Eu³⁺ is a potential red‐emitting phosphor for near‐UV LEDs. Emission spectra of LiBaPO₄:Dy³⁺ phosphors showed efficient blue (481 nm) and yellow (574 nm) bands, which originated from ⁴ F_9/2 → ⁶H_15/2 and ⁴ F_9/2 → ⁶H_13/2 transitions of the Dy³⁺ ion, respectively. The 574 nm line is more intense than the 481 nm lines, which indicates that the site Dy³⁺ is located with low symmetry. This article summarizes fundamentals and possible applications of optically useful inorganic phosphates with visible photoluminescence of Eu³⁺ and Dy³⁺ ions. Copyright © 2015 John Wiley & Sons, Ltd.