Development of the glandular and non-glandular leaf hairs of Avicennia marina (Forsskål) Vierh.

The course of development of the glandular and non-glandular hairs of Avicennia marina was found to be the same up to the three-celled stage. The further cell divisions of the two types of developing hairs differed in their orientation. In the non-glandular hair the cells continued to divide transversely, whereas in the glandular hair the uppermost of the three cells divided longitudinally.
In the mature hairs of both types, the peripheral wall of the cell just above the basal cell was heavily cutinized. The existence of narrow canals in the cuticle of the secretory cells of the glandular hairs was confirmed. The homology of the glandular and non-glandular hairs is discussed and it is concluded that the two types are phylogenetically related.     

羽叶薰衣草表皮毛的发育解剖学研究

对羽叶薰衣草(LavandulapinnataL.)茎和叶上两种表皮毛(腺毛和非腺毛)发育的解剖学观察表明,两者的发生都源于茎或叶的原表皮细胞,但外部形态、发育过程及功能明显不同。腺毛有头状腺毛和盾状腺毛两种类型,均由1个基细胞、1个柄细胞和头部细胞构成。头状腺毛的头部只有1个或2个分泌细胞,盾状腺毛由8个分泌细胞构成头部。非腺毛由3-20个细胞组成,可分为三种类型:单列不分枝、二叉分枝和三叉及三叉以上多分枝的树状分枝。非腺毛的顶部细胞由基部到顶部逐渐变细,先端成尖形。腺毛发育由原表皮细胞经两次平周分裂形成,由于柄细胞和头部细胞所处的分化状态不同而发育成两类腺毛。非腺毛由非腺毛原始细胞经二次或多次平周分裂和不均等分裂,再发育成数个至二十多个子细胞。     

Photoreceptor ultrastructure in the Antarctic mussel shrimp Acetabulastoma (Crustacea; Ostracoda), a parasite of Glyptonotus antarcticus (Crustacea; Isopoda)

The ultrastructure of the nauplius eye of the tiny Antarctic ostracode Acetabulastoma sp. is described and conclusions about its possible function are drawn. Each of the three eye-cups measures approximately 20 μm in diameter and is optically isolated from its neighbour by screening pigments, which are contained in pigment cells behind a tapetum of concentrically arranged, ca. 1-μm-long and 0.1-μm-thick, crystals. Three and sometimes four separate rhabdoms with microvilli measuring 50–60 nm in diameter project from the concave side of the tapetum up to 5 μm deep into the eye-cup interior, which is filled by the retinula cell bodies with their spherical nuclei and various organelles. Desmosomes and microtubules are seen and light-induced cell or membrane damage was minimal. The observations suggest that the Acetabulastoma eye has photoreceptors that can tolerate an exposure to bright light and it may be used to inform its owner of the approach of danger, the depth of water, and/or the season. Accepted: 27 August 1998     

Cytoarchitecture and pattern of cytoplasmic streaming in root hairs ofMedicago truncatula during development and deformation by nodulation factors

Summary The cytoarchitecture and the pattern of cytoplasmic streaming change during the development of root hairs ofMedicago truncatula and after a challenge with nodulation (Nod) factors. We measured the speed and orientation of movement of 1–2 μm long organelles. The speed of organelle movement in cytoplasmic strands in the basal part of growing root hairs is 8–14 μm/s and is of the circulation type like in trichoblasts, bulges before tip-growth initiation, and full-grown hairs. In the subapical area of growing hairs, reverse-fountain streaming occurs discontinuously at a slower net speed. The reason for the slower speed is the fact that organelles often stop and jump. Reverse-fountain streaming is a pattern in which the main direction of organelle transport reverses 180 degrees before the cell tip is reached. Within minutes after their application to roots,Rhizobium leguminosarum-derived Nod factors, cause an increase and divergence in the subapical cytoplasmic strands. This phenomenon can best be observed in the growth-terminating hairs, since in hairs of this developmental stage, subapical cytoplasmic strands are transvacuolar. First, the tips of these hairs swell. The organelle movement in the swelling tip increases up to the level normal for circulation streaming, and the number of strands with moving organelles increases. When a new polar outgrowth emerges, reverse-fountain streaming is set up again, with all its characteristics like those seen in growing hairs. This outgrowth may obtain a new full root hair length, by which these hairs may become twice as long as nonchallenged hairs. Dedicated to Professor Walter Gustav Url on the occasion of his 70th birthday     

Long,smooth hair sensilla on the spider leg coxa: Sensory physiology,central projection pattern,and proprioceptive function (Arachnida,Araneida)

Summary Rows of long, smooth hair sensilla situated on both sides of the leg coxae were examined in the spider Cupiennius salei (Ctenidae). The hair shafts point into the space between adjacent legs and are deflected when the hairs of one coxa touch the cuticle of the neighboring coxa. 1. Unlike the serrated hair shafts of the ubiquitous tactile and chemosensitive setae of spiders, these hairs are entirely smooth. At their base they are articulated in a socket with an asymmetrical groove that determines the direction of hair deflection. Hair shafts are up to 1000 m long. The exact grouping of smooth hairs in rows is typical of the coxae for each pair of legs. 2. Unlike the other, multiply innervated cuticular sensilla of spiders, smooth hairs are supplied by only a single mechanosensitive neuron. This is confirmed by electrophysiological recordings from single hairs. Threshold deflection to elicit a spike response lies near 1°. The response to maintained, step-like stimuli declines rapidly. 3. All central endings of these hair receptors in the fused segmental ganglia are confined to dorsal neuropil of the ipsilateral neuromere. The specific arborization pattern resembles an elongated, three-pronged fork with a long central prong. Topography, natural stimulus situation, and the phasic response characteristic of smooth hairs suggest that spiders use these sensilla to monitor the relative distance between leg coxae during locomotion.     

Microprojectile particle effect on stable transformation of black spruce via bombardment

Three types of microprojectile particles, 1.0-μm gold, 1.3-μm tungsten, and 1.6-μm gold, were studied for their effectiveness on genetic transformation of black spruce via bombardment with somatic embryos as the target tissue. Different particles resulted in different levels of transient expression of theGUS reporter gene; 1.0-μm gold particles produced the highest level of expression, and 1.6-μm gold particles produced the lowest level. Particle type also affected stable transformation; 1.0-μm gold particles had a 10-fold higher stable transformation efficiency than did 1.6-μm gold particles and a 2-fold higher efficiency than did 1.3-μm tungsten particles. This study indicates that microprojectile particle type and size are important in bombardment-mediated plant transformation.     

Root hair elongation is inhibited by hypaphorine, the indole alkaloid from the ectomycorrhizal fungus Pisolithus tinctorius, and restored by indole-3-acetic acid

Hypaphorine, the major indolic compound isolated from the ectomycorrhizal fungus Pisolithus tinctorius, controls the elongation rate of root hairs. At inhibitory concentrations (100 μM), hypaphorine induced a transitory swelling of root hair tips of Eucalyptus globulus Labill. ssp. bicostata. When the polar tip growth resumed, a characteristic deformation was still visible on elongating hairs. At higher hypaphorine concentrations (500 μM and greater), root hair elongation stopped, only 15 min after application. However, root hair initiation from trichoblasts was not affected by hypaphorine. Hypaphorine activity could not be mimicked by related molecules such as indole-3-acetic acid (IAA) or tryptophan. While IAA had no activity on root hair elongation, IAA was able to restore the tip growth of root hairs following inhibition by hypaphorine. These results suggest that hypaphorine and endogenous IAA counteract in controlling root hair elongation. During ectomycorrhiza development, the absence of root hairs might be due in part to fungal release of molecules, such as hypaphorine, that inhibit the elongation of root hairs. Received: 27 October 1999 / Accepted: 14 March 2000     

Hair regeneration during moulting in the spiderCiniflo similis (Araneae,Dictynidae)

Summary The mechanoreceptive and chemoreceptive hairs on the legs of the cribellate spiderCiniflo similis were examined during the moulting cycle. In mechanoreceptive hairs the new hair shaft is formed around the extended dentrites, which emerge from near the tip of the newly forming hair and continue to the old sensillum within the extended dendritic sheath. Thus there is no ecdysial canal in the base of the hair shaft as found in insect mechanoreceptive hairs. The dendritic connection with the old hair is maintained until shortly before ecdysis by which time new tubular bodies have developed in the same dendrites at the base of the new hair. In chemoreceptive sensilla the new hair shaft is also formed around the elongated outer segment of the dendrites (19 chemosensitive and 2 mechanosensitive). The two mechanosensitive dendrites develop new tubular bodies at the base of the hair. As ecdysis occurs the old dendritic sheath and dendrites are snapped off at the tip of the new hair but the pore remains open. The ultrastructural evidence indicates that the roles of the three main enveloping cells are as follows: The dendritic sheath cell secretes the dendritic sheath, the middle enveloping cell forms the hair shaft while the outer enveloping cell forms the socket. This pattern corresponds closely to that observed in insecta sensilla. The extreme length of the chemoreceptive dendrites during moulting is mentioned in connection with receptor function. The unique multi-layered nature of the middle enveloping cell is seen as a device for the formation of regularly occurring rows of small spines on the shaft of the hair.     

LEAF HAIRS IN ENCELIA (ASTERACEAE)

Four different kinds of leaf hairs occur in Encelia species. These are unicellular-based and multicellular-based uniseriate hairs, moniliform hairs, and biseriate glandular hairs. The unicellular-based uniseriate hairs appear responsible for increased leaf spectral reflectance by species within the genus. In particular, it appears that elongation of the distal cell of the uniseriate hair is necessary for increased leaf reflectance.     

The morphogenesis of cell hairs on Drosophila wings

We describe in this paper details of morphogenesis of wing hairs in Drosophila pupae. The ultimate objective is to relate specific protein components used in hair construction to specific components produced in the rapidly changing patterns of gene expression that are characteristic for the period of hair differentiation in wing cells (H. K. Mitchell and N. S. Petersen, 1981, Dev. Biol. 85, 233-242). Hair extrusion to essentially full size occurs quite suddenly at about 34 hr (postpupariation) and this is followed by deposition of a double-layer of cuticulin during the next 4 to 5 hr. Extreme changes in shape of cells and hairs, probably related to actin synthesis, then occur for the next 5 to 6 hr. Deposition of fibers within the hairs and on hair pedestals follows. Formation of cuticle on the cell surface begins and continues until some time in the 60-hr range. It appears that cuticle is formed only on the cell surface and not in hairs or on the top of hair pedestals. The protein synthesis patterns associated with these events are described.     

The seasonal abundance and vertical distribution of the <3-μm phytoplakton in the north basin of Lake Biwa

The seasonal changes in the size-fractionated chlorophylla concentrations (<3 μm, 3 to 25 μm, and >25 μm) were investigated at a pelagic site of the north basin of Lake Biwa during June to December 1985. Autofluorescing plankton cells in the <3-μm fractions were also examined using the fluorescein isothiocyanate staining epifluorescence microscopic technique. The <3-μm phytoplankton (usually dominated by chroococcoid cyanobacteria except for a few cases dominated by small eukaryotes) showed a clearly different pattern of seasonal change compared with the larger fractions. That is, from August to early September, chlorophylla of the larger fractions declined considerably, while the <3-μm chlorophylla did not decrease significantly. Moreover, cyanobacterial cell density in the <3-μm fraction showed a maximum value (2–3.5×10⁵ cells·ml⁻¹) during this period. The relative contribution of the <3-μm chlorophylla to the total chlorophylla increased from <5% to 45% during the course of this change. No clear vertical trend in the distribution and composition of the <3-μm phytoplankton was found, except that relatively large cyanobacteria (>4 μm³) appeared at a depth of 15m but not at 0,5 and 10 m from late July to August. These large cells were also found in November and December. The drastic seasonal change of phytoplankton size structure occurring in this basin was discussed in relation to grazing, nutrient depletion and sinking. Contribution from Otsu Hydrobiological Station, Kyoto Univeristy (No. 308, foreign language series).     

Studies on the Development of Glandular Hairs in Nymphoides peltatum and the Ultrastructure During Their Secretory P

Each glandular hair of Nyrnphoides peltaturn (Gmel.) O. Kuntz consisted of only one row of cylindar cells with secretory function. The hairs originated from the protoderm cells on the adaxial surface of the second leaf primordium from the shoot apex. Cells of the glandular hairs prossessed dense cytoplast during the secretory period, but the vacuoles were very small. There were not only abundant mitochondria, Golgi bodies and endoplasmic reticulum in the glandular hair cells, but also many plasmodesmata. The authors' research indicated that the mucilage was carried to the edge of the cells by the membranous multilamellar bodies and the vesicles from both Golgi bodies and endoplasmic reticulum. The mucilage was secreted extracellularly by either exocytosis or ecrine secretion. The side walls of the glandular hairs swelled because of mucilage mass accumulation in the walls. The mucilage, being tested to be composed of polysaccharides and a trace of protein, played an important role in protecting the development of the vegetative buds of N. peltatum.     

ULTRASTRUCTURAL EVIDENCE FOR SECRETORY PHASES IN THE LIFE HISTORY OF STIGMATIC HAIRS OF COTTON: A DRY TYPE STIGMA

Stigmatic hairs of the cotton flower were studied through their developmental stages up to anthesis. Stigmatic hairs invariably develop from a densely straining band of epidermal cells opposite the transmitting tissue cells. At anthesis, these are single cell structures measuring up to 300 μm long. At the 5-mm stage of stylar length (7–10 days before anthesis), some stigmatic hair cells begin to accumulate an osmiophilic substance between the plasmalemma and the cell wall, possibly synthesized in the endoplasmic reticulum. This material is apparently never secreted outside the cell wall. Immediately following this secretory phase in some stigmatic hair cells a second secretory phase starts. A dense osmiophilic substance, different in appearance from the previous phase, accumulates in the vacuoles of each hair cell. Concomitantly, dimorphism develops in the cytoplasmic densities of stigmatic hair. Some stigmatic hair cytoplasm appears very dense and shows signs of degeneration while other cytoplasm appears normal. A third secretory phase, which begins at anthesis, occurs in the normal hair cells. This phase is characterized by enhanced activity in the cytoplasm of the endoplasmic reticulum and Golgi apparatus. Large vesicles containing granular material are seen fusing with the plasmalemma. Coincident with this activity there is dissolution of the middle layers of the cell wall and the cuticle is ruptured at various points. The dense osmiophilic substance that had accumulated in the vacuole breaks down into fine granular material. Significance of these changes is discussed in relation to the pollen germination mechanism on the dry type stigma of cotton.     

Fine structure of the tibiotarsal and pretarsal sensory organs in Monobella grassei banyulensis Deharveng (Collembola : Neanuridae)

The fine structure of the tibiotarsal and pretarsal sensory organs of Monobella grassei banyulensis Deharveng (Collembola : Neanuridae) has been examined by electron microscopy.Three types of sensory organs have been observed. (1) the most numerous setae of the tibiotarsus are classic mechanosensitive setae with one bipolar sensory cell, whose distal outer segment ends in a tubular body. (2) Two small setae are arranged on each side of the basal part of the claw; they show 3 sensory cells, 2 of which are mechanosensitive cells of the scolopidial type; the outer segments of the 2 mechanosensitive cells end at the base of the sensory hair. The dendrite of the 3rd sensory cell extends into the hair shaft. (3) Two similar chordotonal sensilla link the tibiotarsus and the pretarsus; each sensillum is composed of 2 bipolar sensory cells enveloped in sheath cells. The first type of sensory organ shows the characteristics of insect exteroceptive mechanosensitive hairs. The mechanosensitive cells of the 2nd and 3rd tibiotarsus sensory organs are probably proprioceptive and control the movements of the pretarsus in relation to the tibiotarsus. Two features are noteworthy: (1) the association of the scolopidial cells with a chemosensitive one has never been observed in other insect sensory organs, except in the Collembola; and (2) there is an important morphological diversity in the ciliary roots of the various scolopidial cells, which are in other respects very similar.     

Trichome morphology provides phylogenetically informative characters for Tremandra, Platytheca and Tetratheca (former Tremandraceae)

Summary Trichomes of Tremandra R.Br. ex DC., Platytheca Steetz and Tetratheca Sm. (Elaeocarpaceae, former Tremandraceae), together with two outgroup species of Elaeocarpus L., are illustrated using scanning electron microscopy, and their distribution on various plant organs is documented. Various trichomes types were identified that relate taxa: simple hairs, stellate hairs, short glandular trichomes, long glandular trichomes, and three forms of tubercules. Both outgroup and ingroup taxa have simple hairs. Stellate hairs are confirmed as unique to Tremandra. Prominent and sculptured multicelled tubercules, some bearing a stout hair, are characteristic of Platytheca. Smaller multicelled tubercules occur in both Platytheca and Tetratheca, except for the Western Australian taxon Te. filiformis Benth. (possibly plesiomorphic). Unicellular tubercules (papilla) characterise two species of Tetratheca. Short glandular trichomes, usually found on the ovary, also occur in both of these genera but not in all species (possibly secondary losses), while long glandular trichomes, usually on stems and leaves, occur only in some groups of Tetratheca. Within Tetratheca, Western Australian taxa that have five-merous flowers fall into three ‘groups’: seven species (together with one from South Australia) that have short glandular trichomes but no long glandular trichomes; six species that have long glandular trichomes but no short glandular trichomes; and four species that have both trichome types. All other species of Tetratheca have four-merous flowers and form two ‘groups’: 12 eastern species (including one from South Australia) that have both short glandular trichomes and long glandular trichomes; 4 western species and six eastern species that lack short glandular trichomes. On the basis of these characters, a phylogenetic hypothesis for the three genera is presented.     

Morphology and secretion of glandular trichomes in Tamus communis

Light and scanning electron microscopical investigations were carried out to study distribution, morphology and secretion of glandular trichomes during leaf development in Tamus communis . During leaf growth glandular trichomes arise continously from single protodermal cells. At maturity, they are composed of a 6-celled gland head, a secretory neck cell, an "endodermal" cell, and one basal or reservoir cell. During the early stage of secretion, several regularly arranged crater-like pores differentiate on the cuticular surface of the gland head. Through these pores (1–1.5 μm in diameter), the secretion flows out as a thin film or as rods (0.4 μm in diameter) spreading on the trichomes and on the leaf surface. Histochemical tests indicate that the secretion is composed of a small amount of carbohydrates and an abundant fraction of lipophilic material. Proceeding towards senescence, the wall degeneration of the gland head gives rise to a strong histochemical reaction for insoluble polysaccharides. The results presented are compared with those of other investigations on the pattern of secretion in glandular trichomes.     

紫苏腺毛的形态发生研究

紫苏叶上有两种腺毛：质状腺毛和头状腺毛。两者都具１个基细胞、１个柄细胞和头部。前者的头部可由１、２、４或８个分泌细胞组成,扩展成质状;后者的头部由１、２或４个分泌细胞组成,聚成圆球状。两种腺毛的原始细胞都来源于原表皮细胞,经两次平周分裂产生基细胞、柄细胞和顶细胞。在腺毛后期的形态发生中,柄细胞的分化状态决定腺毛的类型。若柄细胞保持扁平关且处于分生状态时,其顶细胞将发育成质状腺毛的头部;若柄细胞纵向     

Glandular Hair Formation in Origanum Species

Eleven Origanum species were investigated in this study. Inall these species, leaf glandular hairs have the same structureand they have been found to follow a common developmental pattern.They originate from a single protodermal cell which dividessuccessively parallel to leaf surface to give rise to the footcell, the stalk cell and the mother cell of the head. The latterundergoes a series of symmetric and asymmetric anticlinal divisionsresulting in a 12-celled head (four small cells in the centreand eight large cells peripherally arranged). Determinationof the glandular scale morphology within the Lamiaceae generaand further comparison between the various gland types wouldbe helpful to systematics. Origanum species, Lamiaceae, glandular hair, development     

Impact of medium volume and oxygen concentration in the incubator on pericellular oxygen concentration and differentiation of murine chondrogenic cell culture

Previous studies have demonstrated that oxygen environment is an important determinate factor of cell phenotypes and differentiation, although factors which affect pericellular oxygen concentration (POC) in murine chondrogenic cell culture remain unidentified. Oxygen concentrations in vivo were measured in rabbit musculoskeletal tissues, which were by far hypoxic compared to 20% O₂ (ranging from 2.29 ± 1.16 to 4.36 ± 0.51%). Oxygen concentrations in murine chondrogenic cell (C3H10T1/2) culture medium were monitored in different oxygen concentrations (20% or 5%) in the incubator and in different medium volumes (3,700 or 7,400 μl) within 25-cm² flasks. Chondrogenic differentiation was assessed by glycosaminoglycan production with quantitative evaluation of Alcian blue staining in 12-well culture dishes. Expression of chondrogenic genes, aggrecan, and type II collagen α1, was examined by quantitative real-time polymerase chain reaction. Oxygen concentrations in medium decreased accordingly with the depth from medium surface, and POC at Day 6 was 18.99 ± 0.81% in 3,700-μl medium (1,480-μm depth) and 13.26 ± 0.23% in 7,400-μl medium (2,960-μm depth) at 20% O₂ in the incubator, which was 4.96 ± 0.08% (1,480-μm depth) and 2.83 ± 0.42% (2,960-μm depth) at 5% O₂, respectively. The differences of POC compared by medium volume were statistically significant (p = 0.0003 at 20% and p = 0.001 at 5%). Glycosaminoglycan production and aggrecan gene expression were most promoted when cultured in moderately low POC, 1,000 μl (2,960-μm depth) at 20% O₂ and 500 μl (1,480-μm depth) at 5% O₂ in 12-well culture dishes. We demonstrate that medium volume and oxygen concentration in the incubator affect not only POC but also chondrogenic differentiation.     

Ultrastructure of the marine predatory flagellate <Emphasis Type="Italic">Metromonas simplex</Emphasis> Larsen et Patterson, 1990 (Cercozoa)

The ultrastructure of the marine predatory flagellate Metromonas simplex Larsen et Patterson was studied. The cell is surrounded by a low-contrast fibrous layer composed of thin hairs covered by a thin bilayer membrane and an outer layer of thin short fibers. The plasmalemma lies under these layers. The predator captures whole cells of the prey, usually bodonids or chrysomonads. The cytostome as a cell pocket is undetectable. The long flagellum bears very thin mastigonemes (hairs) with lengths of 0.8–1.0 μm; the short flagellum is naked and reduced in length. The transitional zone lacks spirals or other additional elements. The transversal plate is elevated on the cell surface. The flagellar root system is very simple and has one microtubular band which originates near the kinetosomes. The latter are parallel to each other and interconnected by fibrous bridges. The vesicular nucleus, Golgi apparatus, and endoplasmic reticulum are of typical structures. The oval mitochondria of 0.6–2.5 μm contain lamellar cristae. The cylindrical extrusomes (trichocysts) found in the cytoplasm have lengths of 1.0–1.4 μm and diameters of 0.12–0.08 μm. The trichocysts have a wheel-shaped structure with 13 spokes visible in cross-sections. The contractile vacuole is absent. The similarity that M. simplex shares with Metopion fluens Larsen et Patterson, cryothecomonads, and other predatory flagellates is discussed.