Glandular hairs in the genusDrosera (Droseraceae)

On the leaves and sepals of 52 species, representing all sections of the genusDrosera except one, 14 different types of glandular hairs were found: two-celled papillae, peltate scales, several types with unbranched, bi- or multiseriate stalk with a two- or multicellular gland, and one type with a multiseriate stalk and a two-armed gland. The combination of these hairs and the presence of non-glandular hairs confirm the actual classification of the genus. In combination with simple morphological characters (e.g., the type of insertion of the petiole) glandular hairs facilitate the identification of species even in the pharmaceutically important cut crude drug.     

Anti-herbivore structures of Paulownia tomentosa: morphology, distribution, chemical constituents and changes during shoot and leaf development

Background and Aims: Recent studies have shown that small structures on plant surfacesserve ecological functions such as resistance against herbivores.The morphology, distribution, chemical composition and changesduring shoot and leaf development of such small structures wereexamined on Paulownia tomentosa. Methods: The morphology and distribution of the structures were studiedunder light microscopy, and their chemical composition was analysedusing thin-layer chromatography and high-performance liquidchromatography. To further investigate the function of thesestructures, several simple field experiments and observationswere also conducted. Key Results: Three types of small structures on P. tomentosa were investigated:bowl-shaped organs, glandular hairs and dendritic trichomes.The bowl-shaped organs were densely aggregated on the leavesnear flower buds and were determined to be extrafloral nectarines(EFNs) that secrete sugar and attract ants. Nectar productionof these organs was increased by artificial damage to the leaves,suggesting an anti-herbivore function through symbiosis withants. Glandular hairs were found on the surfaces of young and/orreproductive organs. Glandular hairs on leaves, stems and flowerssecreted mucilage containing glycerides and trapped small insects.Secretions from glandular hairs on flowers and immature fruitscontained flavonoids, which may provide protection against someherbivores. Yellow dendritic trichomes on the adaxial side ofleaves also contained flavonoids identical to those secretedby the glandular hairs on fruits and flowers. Three specialtypes of leaves, which differed from the standard leaves inshape, size and identity of small structures, developed nearyoung shoot tips or young flower buds. The density of smallstructures on these leaf types was higher than on standard leaves,suggesting that these leaf types may be specialized to protectyoung leaves or reproductive organs. Changes in the small structuresduring leaf development suggested that leaves of P. tomentosaare primarily protected by glandular hairs and dendritic trichomesat young stages and by the EFNs at mature stages. Conclusions: The results indicate that P. tomentosa protects young and/orreproductive organs from herbivores through the distributionand allocation of small structures, the nature of which dependson the developmental stage of leaves and shoots.     

乌鲁木齐乌头, 新疆毛茛科一新种

该文描述了发现自中国新疆天山北部的毛茛科乌头属一新种,即乌鲁木齐乌头(Aconitm urumqiense),此新种与新疆乌头(A. sinchiangense)近缘。两者的区别在于此新种(乌鲁木齐乌头)的茎无毛,不存在基生叶,总状花序轴和花梗被黄色腺毛,萼片背面疏被柔毛、边缘被缘毛,上萼片较宽,花瓣唇在顶端啮蚀状,子房幼时疏被柔毛。     

Glandular hairs are a possible means of limiting aphid damage to the potato crop

Glandular hairs on leaves and stems stuck naturally-occurring aphids to field grown plants of Solamim polyadenium, S. berthaultii, and first and second generation hybrid S. tuberosum cv. Pentland Crown ×berthaultii, but none became stuck on Pentland Crown. S. polyadenium had most glandular hairs, stuck most aphids and had fewest free aphids. In the glasshouse, the percentage of stuck aphids was positively correlated with the abundance of glandular hairs, especially on the leaves, so counting the hairs may be a simple preliminary method of screening for aphid-trapping ability.     

Trap diversity and evolution in the family Droseraceae

We review trapping mechanisms in the carnivorous flowering plant family Droseraceae (order Caryophyllales). Its members are generally known to attract, capture, retain and digest prey animals (mainly arthropods) with active snap-traps (Aldrovanda, Dionaea) or with active sticky flypaper traps (Drosera) and to absorb the resulting nutrients. Recent investigations revealed how the snap-traps of Aldrovanda vesiculosa (waterwheel plant) and Dionaea muscipula (Venus’ flytrap) work mechanically and how these apparently similar devices differ as to their functional morphology and shutting mechanics. The Sundews (Drosera spp.) are generally known to possess leaves covered with glue-tentacles that both can bend toward and around stuck prey. Recently, it was shown that there exists in this genus a higher diversity of different tentacle types and trap configurations than previously known which presumably reflect adaptations to different prey spectra. Based on these recent findings, we finally comment on possible ways for intrafamiliar trap evolution.     

菱的腺毛发育及分泌活动的超微结构研究

菱的腺毛由单列圆筒状细胞组成,具有短暂的分泌功能。它们起源于叶片远轴面、叶柄的表皮细胞以及苗端茎轴、花柄的表皮细胞。处于分泌期的腺毛细胞其胞质浓厚,液泡化程度小,细胞具丰富的线粒体、高尔基体。腺毛丧失了分泌功能后即发育成为表皮毛。粘液物质由高尔基体分泌小泡携带至腺毛细胞侧壁,经胞吐与渗透结合的方式分泌至细胞外,粘液的化学成分主要为多糖。     

ASSOCIATION OF MUCILAGE WITH THE LIGULE OF SEVERAL SPECIES OF SELAGINELLA

Mucilage bodies of protein and some polysaccharide were closely associated with ligules of Selaginella kraussiana (Kunze) A. Braun grown in the greenhouse, and Selaginella wallacei Hieron. and Selaginella oregana D.C. Eat. from natural habitats. With S. wallacei and S. oregana, several mucilage bodies were associated with some ligules. No mucilaginous material was associated with the ligules of Selaginella douglasii Hook, et Grev., Selaginella densa Rydb. or Selaginella apoda (L.) Fernald from natural habitats. When stem tips of S. kraussiana and S. douglasii were placed in sterile culture on a medium with sucrose, massive amounts of mucilage appeared around the ligules in the tight interstices of the stem tip leaves and extended out on the surface of the leaves. The mucilage from a cultured stem tip of S. kraussiana contained 0.034 μgm of protein, 14.6 μgm of apparent glucose equivalents as polysaccharide and no significant amounts of phenolics. In stem tips with tightly appressed leaves, either ligules or young leaves could have produced the mucilage; however, in more mature regions of the stem where internodal elongation had separated the leaves, mucilage coated only the apical portions of the ligules and was not associated with leaves. No other possible source of mucilage (bacteria or fungi) was detected among the leaves. When stem tips of S. wallacei, S. densa and S. apoda were placed in culture, mucilage was not produced. Since mucilage is closely associated with the ligule of some species of Selaginella growing in nature, the greenhouse, or tissue culture, the ligule may be glandular.     

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.     

The utilization of nitrogen from insect capture by different growth forms of Drosera from Southwest Australia

Summary Plants of Drosera species, neighbouring noncarnivorous plants, and arthropods on or near each Drosera sp. were collected at 11 contrasting habitat locations in SW Australia. At three of the sites clones of the rare glandless mutant form of D. erythrorhiza were collected alongside fully glandular counterparts. The ¹⁵N value (¹⁵N/¹⁴N natural isotope composition) of insect-free leaf and stem fractions was measured, and the data then used to estimate proportional dependence on insect N (%N_dI) for the respective species and growth forms of Drosera. The data indicated lower %N_dI values for rosette than for self-supporting erect or for climbing vine species. The latter two groups showed an average %N_dI value close to 50%. The %N_dI increased with length and biomass of climbing but not erect forms of Drosera. ¹⁵N values of stems were positively correlated with corresponding values for leaves of Drosera. Leaf material was on average significantly more ¹⁵N enriched than stems, possibly due to delayed transport of recent insect-derived N, or to discrimination against ¹⁵N in transfer from leaf to the rest of the plant. The comparison of ¹⁵N values of insects and arthropod prey, glandless and glandular plants of D. erythrorhiza indicated %N_dI values of 14.3, 12.2 and 32.2 at the respective sites, while matching comparisons based on ¹⁵N of insect, reference plants and glandular plants proved less definitive, with only one site recording a positive %N_dI (value of 10.4%) despite evidence at all sites of feeding on insects by the glandular plants. The use of the ¹⁵N technique for studying nutrition of carnivorous species and the ecological significance of insect feeding of different growth forms of Drosera growing in a large range of habitats is discussed.     

木香薷腺毛形态结构发生发育规律的研究

采用常规石蜡切片法及扫描电镜技术对木香薷(Elsholtzia stauntoni Benth)腺毛发生发育及其规律进行了研究。结果表明：木香薷表皮上主要有两种表皮毛：无分泌细胞的表皮毛与有分泌细胞的腺毛。前者包括单细胞乳头状毛、2~3细胞管状毛、分枝状毛及多细胞管状毛;后者包括头状腺毛与盾状腺毛。成熟头状腺毛头部由1、2或4个分泌细胞构成,头部呈圆球形或半圆球形;成熟盾状腺毛头部由8~12个分泌细胞构成,分泌细胞横向扩展形成盾状头部。木香薷腺毛主要在茎端幼叶处大量发生,从茎端第一对幼叶处开始产生;从幼叶期到成熟期均有腺毛发生,大部分腺毛在幼叶期发生发育,只有极少部分在叶的成熟期进行发生发育。     

A new subspecies ofArenaria grandiflora (Caryophyllaceae) from the Rif mountains (Northern Morocco)

A new subspecies,A. grandiflora subsp.gomarica (Caryophyllaceae), is described from the mountains of northern Morocco. The new taxon is tetraploid and has been confused in the past either with the Balearic endemicA. grandiflora subsp.glabrescens or with the widespreadA. grandiflora subsp.grandiflora, which is also present in the African continent. Detailed morphological analysis showed that plants from the Rif mountains are closely related toA. grandiflora subsp.glabrescens, but differ from it in having a longer calyx, smaller seed size, and a glandular indument on pedicels, leaves and calyx.Arenaria grandiflora subsp.gomarica can be distinguished from all infraspecific taxa of theA. grandiflora complex by the combined presence of a heterotrichous (simple and pluricellular eglandular hairs, glandular hairs) indument on the inflorescences and glandular hairs on the calyx.     

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.     

Glandular hairs on Solatium polyadenium lessen damage by the Colorado beetle

Four-lobed glandular hairs on the leaves and stems of the potato species Solanum polyadenium provide a form of resistance to larvae of the Colorado beetle Leptinotarsa decemlineata. On contact, a sticky material was discharged from these hairs trapping a few larvae and encasing the feet of others. Larvae with encased feet fell from the plants to die.     

Phytochemistry of the Carnivorous Sundew Genus Drosera (Droseraceae) – Future Perspectives and Ethnopharmacological Relevance

Species of the carnivorous genus Drosera L. have long been a source of valuable natural products. The various phytochemicals characteristic of these species, particularly 1,4‐naphthoquinones and flavonoids, have contributed to the diverse utilization of sundews in traditional medicine systems worldwide. A growing number of studies have sought to investigate the comparative phytochemistry of Drosera species for improved sources of pharmaceutically important compounds. The outcomes of these studies are here collated, with emergent trends discussed in detail. Important factors which affect production of secondary metabolites in plants are critically examined, such as environmental influences and in vitro culture, and recommendations subsequently presented based on this. Explicitly, the current review aims to i) present an updated, comprehensive listing of the phytochemical constituents of the genus (including quantitative data where available), ii) summarize important factors which may influence the production of phytopharmaceuticals in plants, and iii) recommend guidelines for future research based on the above, including improved standardization and quality control. We have also included a section discussing future perspectives of research on Drosera spp. based on three different research lines i) the potential to produce much needed lead compounds for treatment of tuberculosis, ii) the potential role of anthocyanins in nitrogen transport, and iii) research into ‘Natural Deep Eutectic’ solvents produced by Drosera spp. in the droplets or ‘dew’ employed to capture insect prey.     

东北桤木叶表皮盾状腺毛的形态及其变化过程

利用电镜扫描技术,观察东北桤木叶片表面,发现其远轴面表皮上具有盾状腺毛。其由2个基细胞、4个柄细胞和20～25个头部细胞组成,随着分泌物质的积累,细胞逐渐破裂。幼叶远轴面表皮无盾状腺毛,仅有气孔分布。观察东北桤木叶片横切面,发现其为异面叶,远轴面表皮上的盾状腺毛细胞与叶脉维管组织相连。外文资料显示用于表述桤木属表皮上的盾状腺毛的名词较多,该毛状体应为“Peltate glandular hairs”。同时建议对“Glandular scales”、“Peltate gland”、“Peltate scale”、“Peltate glandular hairs”等名词进行规范统一。另外有关东北桤木叶表皮上毛状体从原表皮细胞的发生过程及其分泌物的成份,需进一步研究。     

Observations on the trapping of the whitefly Bemisia tabaci by glandular hairs on tomato leaves

Observations were made on the role of glandular leaf hairs of four tomato cultivars in trapping cotton whitefly, Bemisia tabaci, adults. Dead, trapped whitefly occurred in similar numbers on both the upper and lower surfaces of leaves even though glandular hairs were denser on the former. Females constituted 58% of untrapped but 86% of trapped adults, many becoming trapped during oviposition which occurred mainly on the lower surfaces. Of the four cultivars studied, Strain B trapped more whitefly than Ace, Marglobe or Moneymaker.     

Glandular trichomes and essential oil constituents ofCalamintha menthifolia (Lamiaceae)

Plant material ofCalamintha menthifolia was collected from two populations grown in the Vikos-Aoos area (NW. Greece). The structure and ontogeny of the glandular trichomes and the chemical composition of the secreted essential oil were studied. The leaves ofC. menthifolia have numerous glandular trichomes of three morphological distinct types: 1) glandular scales with a unicellular foot and stalk, and a 12-celled head, 2) glandular hairs with a unicellular foot and stalk, and a unicellular pear-shaped head and 3) glandular hairs with a unicellular foot, a bicellular stalk and a unicellular elongated head. Qualitative and quantitative GC-MS analyses of the essential oils revealed piperitone oxide as the main constituent in both populations. In the light of these results the relationships beweenC. menthifolia and other members of theSatureja group as well as its taxonomy are discussed.     

Glandular Hairs and Essential Oil in Developing Leaves of Ocimum basilicum L. (Lamiaceae)

The types of glandular hairs and their pattern of distributionon leaves of Ocimum basilicum L. at different stages, were investigated.Their essential oil at the various stages was chemically analysed.The density of the glandular hairs appears to be very high onyoung meristematic leaves and on meristematic regions of olderleaves. When the leaf regions start to expand no new glandularhairs are produced and their density decreases. The essentialoil differs in the percentage of some of its components betweenyoung and mature leaf regions.Copyright 1993, 1999 AcademicPress Ocimum basilicum, sweet basil, glandular hairs, leaf development, essential oil, cugenol, methyl chavicol, 1,8-cineole     

Saussurea balangshanensis sp. nov. (Asteraceae), from the Hengduan Mountains region,SW China

Saussurea balangshanensis, based on populations from Balang Mountain in the Hengduan Mountains region, SW China, is described and illustrated as a new species of Asteraceae. It can be distinguished from other species in Saussurea by its concolorous leaves, swollen and hollow upper stems, articulate hairs and stipitate glandular hairs, laciniate margins of uppermost stem leaves, numerous and sessile capitula, and narrow involucre. Based on nucleotide sequence data from the internal transcribed spacer (ITS), phylogenetic analyses also support the recognition of these populations as representing a new species. The new species is known only from a single location in Balang Mountain, at elevations of 4500–4700 m. Its habitat can be easily disturbed or destroyed by a tourist arterial highway and the over grazing. We propose that the species should be listed as Critically Endangered based on the International Union for Conservation of Nature Red List Categories and Criteria B2a.     

Effect of adult females' predation risk on oviposition site selection in a water strider

In many egg‐laying species, females avoid ovipositing at sites where the predation risk is high. Previous studies have mainly focused on the risk for offspring. The effect of predation risk for the females has been considered in some taxa in which parents spend much time at an oviposition site for parental care or mating (e.g., birds, amphibians). In species in which females do not perform activities other than oviposition at sites, the effect of predation risk for females on oviposition site selection has been rarely investigated. We examined whether the predation risk for ovipositing females affects the decision on oviposition in the water strider Aquarius paludum insularis (Motschulsky) (Heteroptera: Gerridae). Adult A. paludum are preyed upon by a backswimmer, Notonecta triguttata (Motschulsky) (Heteroptera: Notonectidae), but N. triguttata does not prey upon eggs or early instars of A. paludum. We allowed female A. paludum to oviposit under one of three conditions: in presence of N. triguttata, in presence of its chemicals, and in absence of the predator or its cues (control). Female A. paludum less frequently oviposited in presence of N. triguttata than in its absence. Oviposition frequency did not differ between females in presence of chemicals of N. triguttata vs. those in the control. Female A. paludum recognized the predation risk upon themselves from the presence of N. triguttata and avoided ovipositing. This study is the first to directly show that the predation risk upon ovipositing females changes oviposition site selection in species in which the time spent at an oviposition site is short.