Composition of rugosa rose (Rosa rugosa thunb.) hydrolate according to the time of distillation

Rugosa rose (Rosa rugosa Thunb.) is one of the most common rose species in Poland. It has mild soil and climate requirements and is resistant to low temperatures. Rugosa rose hips are a valuable raw material used in food and pharmaceutical industries, while flowers and petals may be a source of fragrant products, such as essential oil and hydrolate. The main aim of this study was to verify usefulness of dried R. rugosa petals for essential oil and hydrolate production. We also assessed the use of rugosa rose petals remaining after oil distillation for hydrolate production.The R. rugosa dried petals immersed in water were subjected to simple distillation and five fractions of primary rose hydrolate were obtained. In parallel, essential oil from the second sample of petals was obtained by hydrodistillation in Clevenger-type apparatus. The distillation residue was used for obtaining four fractions of secondary hydrolate. The volatiles from hydrolate fractions were isolated by liquid–liquid extraction with diethyl ether. The essential oil and hydrolate volatiles were analyzed by GC–FID–MS.Hydrolate fractions contained similar amounts of volatiles (20–30 mg/L) with the exception of the first fraction of primary hydrolate (60 mg/L). β-Phenylethanol, citronellol, geraniol, and nerol were the main volatile constituents of primary hydrolate. β-Phenylethanol, citronellic acid, and geranic acid were the main volatile constituents of secondary hydrolate. The content of alcohols decreased, while the content of monoterpene esters (citronellyl, neryl, and geranyl acetate) as well as monoterpene acids (citronellic, neric, and geranic acid) increased in successive fractions of both hydrolates.The scent and composition of essential oil and hydrolate obtained from R. rugosa petals were similar to those of rose oil and rose water produced from damask rose (Rosa damascena Mill.). This proves, that rugosa rose distillation products may become an alternative to fragrant damask rose products.     

Odorous and Non-Fatal Skin Secretion of Adult Wrinkled Frog (Rana rugosa) Is Effective in Avoiding Predation by Snakes

The roles played by nonfatal secretions of adult anurans in the avoidance of predation remain unknown. The adult Wrinkled frog (Rana rugosa) has warty skin with the odorous mucus secretion that is not fatal to the snake Elaphe quadrivirgata. We fed R. rugosa or Fejervarya limnocharis, which resembles R. rugosa in appearance and has mucus secretion, to snakes and compared the snakes’ responses to the frogs. Compared to F. limnocharis, R. rugosa was less frequently bitten or swallowed by snakes. The snakes that bit R. rugosa spat out the frogs and showed mouth opening (gaping) behavior, while the snakes that bit F. limnocharis did not show gaping behavior. We also compared the responses of the snakes to R. rugosa and F. limnocharis secretions. We coated palatable R. japonica with secretions from R. rugosa or F. limnocharis. The frogs coated by R. rugosa secretion were less frequently bitten or swallowed than those coated by F. limnocharis secretion. We concluded that compared to different frog species of similar sizes, the adult R. rugosa was less frequently preyed upon by, and that its skin secretion was effective in avoiding predation by snakes.     

Hybridization with invasive Rosa rugosa threatens the genetic integrity of native Rosa mollis

Hybridization between invasive and native species often has severe consequences on fitness and survival of the native relative. We investigated the extent of hybridization between the neophyte Rosa rugosa and native R. mollis, an endangered species in Germany. Rosa mollis is found in only one large population in Germany close to the Baltic coast, which has been heavily invaded by R. rugosa for at least 60 years. We analysed all individuals of R. mollis from this mixed population using microsatellite markers and morphological characters and compared these data with those from allopatric populations of R. mollis and R. rugosa. In the mixed population we identified nine plants (45% of the population) as hybrids between R. mollis (seed parent) and R. rugosa (pollen parent) by the presence of microsatellite alleles private for R. rugosa. These individuals were also morphologically intermediate between the parental species. Gene flow from R. mollis into R. rugosa was negligible. We detected a very low genetic diversity and a low number of seeds per hip in the mixed population of R. mollis, pointing to genetic depletion and low fitness. In the light of these results and the difficulties in removing invasive R. rugosa from European coastlines, we discuss possible conservation strategies for this endangered population. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 170 , 472–484.     

Molecular cloning and expression analysis of RrNHX1 and RrVHA-c genes related to salt tolerance in wild Rosa rugosa

Salt stress is one important factor influencing the growth and development of plants, and salt tolerance of plants is a result of combined action of multiple genes and mechanisms. Rosa rugosa is not only an important ornamental plant, but also the natural aromatic plant of high value. Wild R. rugosa which is naturally distributed on the coast and islands of China has a good salt tolerance due to the special living environment. Here, the vacuolar Na⁺/H⁺ reverse transporter gene (NHX1) and the vacuolar H⁺-ATPase subunit C gene (VHA-c) closely related to plant salt tolerance were isolated from wild R. rugosa, and the expression patterns in R. rugosa leaves of the two genes under NaCl stress were determined by real-time quantitative fluorescence PCR. The results showed that the RrNHX1 protein is a constitutive Na⁺/H⁺ reverse transporter, the expression of the RrNHX1 gene first increased and then decreased with the increasing salt concentration, and had a time-controlled effect. The RrVHA-c gene is suggestive of the housekeeping feature, its expression pattern showed a similar variation trend with the RrNHX1 gene under the stress of different concentrations of NaCl, and its temporal expression level under 200 mM NaCl stress presented bimodal change. These findings indicated that RrNHX1 and RrVHA-c genes are closely associated with the salt tolerance trait of wild R. rugosa.     

Invasion of coastal dunes by the alien shrub Rosa rugosa is associated with roads,tracks and houses

Mapping the distribution of invasive alien plant species is significant for testing ecological hypotheses and for guiding effective management. Little is known about the distribution of invasive plants at landscape scale, and the factors controlling their dispersal and establishment are still poorly understood. This is the case for Rosa rugosa, an invasive shrub with negative effects on biodiversity in dune ecosystems of NW Europe. The aim of the study was to identify the factors which determine the distribution of R. rugosa in coastal dunes. In a large semi-natural dune area of NW Denmark (2364 ha) all patches of the species (1321, 1.3–59.1 m²) were GPS mapped. Patch distribution was GIS analysed, based on aerial photographs and vegetation maps. The distance of R. rugosa from the most conspicuous landscape elements was compared with randomly placed reference points. The species had invaded 0.35% of the dune landscape, and it was present in all vegetation types and all parts of the study area. Rosa rugosa patches were slightly smaller in grey dunes than in white dunes and brown dunes, and some of the largest patches were found close to villages. The occurrence of the shrub was positively correlated with distance to the coastline, to roads, tracks and houses. We conclude that the distribution of R. rugosa is determined by both natural and anthropogenic factors. It is further discussed how these factors may control dispersal and establishment of the species, and how the results can be used for improved management of coastal dunes.     

Root-Associated Fungi of Rosa rugosa Grown on the Frontal Dunes of the Baltic Sea Coast in Lithuania

The aim of the present study was to assess fungal communities associated with fine living roots of Rosa rugosa Thunb grown on the frontal dunes of Curonian Spit at the Baltic Sea coast in Lithuania. The roots of R. rugosa were sampled at five sites (Nida, Preila, Pervalka, Juodkrante and Smiltyne) situated at a distance ca. 5–15 km from each other. Direct amplification, cloning and sequencing of fungal ITS rRNA from the fine roots resulted in 134 high-quality sequences, representing 31 fungal taxa among which saprotrophs and endophytes Mycena sp. (14.2 %), Tumularia sp. (14.2 %), Penicillium spinulosum (11.9 %) and Cadophora malorum (9.0 %) were most common. Arbuscular mycorrhizal fungi including Entrophospora baltica (0.7 %) and Rhizophagus irregularis (0.7 %) and potentially root pathogenic fungi—Ceratobasidium sp. (4.5 %), Fusarium oxysporum (3.0 %), Fusarium culmorum (0.7 %) and Ilyonectria crassa (0.7 %)—were also detected at low proportions. In conclusion, the results demonstrated that the fine roots of R. rugosa are inhabited by various groups of fungi. Although saprotrophs and endophytes were dominant, the detection of arbuscular mycorrhizal fungi indicated that these may be important for mineral nutrition of R. rugosa established on dry and poor fertility coastal dunes.     

Antennal responses of an oligolectic bee and its cleptoparasite to plant volatiles

Cleptoparasitic or cuckoo bees lay their eggs in nests of other bees, and the parasitic larvae feed the food that had been provided for the host larvae. Nothing is known about the specific signals used by the cuckoo bees for host nest finding, but previous studies have shown that olfactory cues originating from the host bee alone, or the host bee and the larval provision are essential. Here, I compared by using gas chromatography coupled to electroantennographic detection (GC-EAD) the antennal responses of the oligolectic oil-bee Macropis fulvipes and their cleptoparasite, Epeoloides coecutiens, to dynamic headspace scent samples of Lysimachia punctata, a pollen and oil host of Macropis. Both bee species respond to some scent compounds emitted by L. punctata, and two compounds, which were also found in scent samples collected from a Macropis nest entrance, elicited clear signals in the antennae of both species. These compounds may not only play a role for host plant detection by Macropis, but also for host nest detection by Epeoloides. I hypothesise that oligolectic bees and their cleptoparasites use the same compounds for host plant and host nest detection, respectively.Key words: Macropis fulvipes, Epeoloides coecutiens, Lysimachia punctata, oligolectic oil-bee, floral scent, dynamic headspace, GC-EAD, cuckoo bee, host nest findingBees are the most important animal pollinators worldwide, and guarantee sexual reproduction of many plant species.^1,2 This is especially true for female bees, which collect pollen and mostly nectar for their larvae and frequently visit flowers. For finding and detection of suitable flowers, bees are known to use, besides optical cues,^3,4 especially olfactory signals.^5–8 However, c. 20% of bees do not collect pollen for their larvae by their own, but enter nests of host bees and lay eggs into the broodcells.^1,9 The parasitic larvae subsequently feed the food that had been provided for the host larvae. These so called cuckoo or cleptoparasitic bees can be generalistic, indicating that they use species of several other bee groups as host, whereas others can be highly specialized, laying eggs in cells of only few host species.¹ Until now little is known about the cues used by the cuckoo bees for finding host nests. Nevertheless, Cane¹⁰ and Schindler¹¹ demonstrated that parasitic Nomada bees use primarily visual cues of the nest entrance holes for finding possible nests, and olfactory cues for detection of suitable host nests. The chemical cues used by the cleptoparasites originate from the host bee^10,11 and also pollen,¹⁰ the main larval provision. In most bee species, pollen is mixed together with nectar as larval provision, and both floral resources are known to emit volatiles.^12,13 It is unknown, whether cuckoo bees in search for host nests also use volatiles originating from nectar. While the odours of the host bee used as signal by the cleptoparasites, e.g., cuticiular hydrocarbons and glandular secretions, are often species-specific,¹⁴ the chemical cues from the larval provision may just indicate the presence of pollen in the nest without more specifity. As a consequence cuckoo bees could use species-specific host odours to detect nests of a suitable host, and odours released from the larval provision could indicate to them that broodcells are foraged. However, especially those cuckoo bees with oligolectic hosts foraging pollen only on few closely related plant species,¹ may also use the olfactory signals from host broodcell supplies as more specific cue for host nest detection. Thus the same signal from certain flowers may be used for different informations: for the host bee for host plant and for the cuckoo bee for host nest detection.In this concern I tested oligolectic Macropis (Melittidae, Melittinae) and its specific cuckoo bee, Epeoloides (Apidae, Apinae) by using gas chromatography coupled to electroantennographic detection (GC-EAD) on floral scent of Lysimachia (Myrsinaceae). Macropis is highly specialized on Lysimachia, because it is not only collecting pollen from plants of this genus, but also floral oil. Both floral products are the only provision for the larvae.^1,15 Recently, we have shown that the oil bee Macropis is strongly attracted to floral scent of its oil host Lysimachia though the compounds used for host plant finding are still unknown.⁷ Macropis is the only host of Epeoloides, and larvae of this cleptoparasite only feed on the Lysimachia pollen-oil mixture provided for the larvae of Macropis. Worldwide, there are only 2 species of this genus, one in North America and the other in Europe/Asia.^1,16,17 I hypothesized that both bee species respond to specific Lysimachia compounds, which may be used for host plant as well as host nest detection.The measurements with M. fulvipes (F.) and E. coecutiens (F.) antennae demonstrate that both bees, host as well as cuckoo bee, respond to some scent compounds emitted by inflorescences of Lysimachia punctata L. (Fig. 1), a plant being an important pollen and oil source for M. fulvipes. Macropis responded to much more Lysimachia compounds compared to the cuckoo bee, however, two compounds elicited clear signals in the antennae of both bee species: the benzenoid 1-hydroxy-1-phenyl-2-propanone, and the fatty acid derivative 2-tridecanone. Interestingly, both compounds are also emitted from the floral oil of this plant,⁷ and both compounds were also detected in scent samples collected by dynamic headspace in the entrance of a Macropis nest (Dötterl, unpublished data). Therefore, an Epeoloides female being in search for a host nest can detect volatiles emitted from the provision of the host bee at the entrance of a bee nest, and may use these specific compounds for detection of a Macropis nest provisioned with Lysimachia pollen and oil.Open in a separate windowFigure 1Coupled gas chromatographic and electroantennographic detection of a Lysimachia punctata headspace scent sample using antennae of a female oligolectic Macropis fulvipes and a female cleptoparasitic Epeoloides coecutiens bee. (1) 1-hydroxy-1-phenyl-2-propanone, (2) 2-tridecanone.Present results show that an oligolectic oil-bee as well as its cleptoparasite detects volatiles originating from the host plant of the pollen collecting bee, and that oligolectic bees as well as their cuckoo bees may use the same specific signals for host plant and host nest finding, respectively. Biotests are now needed to test this hypothesis.     

Isolation of 2-phenylethanol biosynthesis related genes and their relationship with 2-phenylethanol accumulation in <Emphasis Type="Italic">Rosa rugosa</Emphasis>

Rosa rugosa is a famous traditional flower in China used not only as a landscape plant but also as a time-honored and valuable aromatic plant. The natural aromatic substance 2-phenylethanol is the major indispensable ingredient of rose flower and rose essential oil. This study adopted R. rugosa ‘Tanghong’ as a test material to isolate 2-phenylethanol biosynthesis related genes RrAADC and RrPAR. The temporal and spatial expression patterns of the two genes in different flower developmental stages and floral organ parts were measured, and the relationship of 2-phenylethanol accumulation to RrAADC and RrPAR expression in R. rugosa was determined. The content of 2-phenylethanol in R. rugosa gradually increased with the degree of flower opening and peaked at the withering stage. The expression level of RrAADC gradually decreased with the degree of flower opening. Meanwhile, the expression level of RrPAR gradually increased from the budding stage to the half opening stage, rapidly decreased at the full opening stage, and slightly increased again toward the withering stage. The content of 2-phenylethanol was the highest in the petals, followed by that in the stamens and pistils. However, this compound was not detected in other parts of the fully opened flower. The expression level of RrAADC peaked in the stamens but was relatively low in the other parts. The expression level of RrPAR was the highest in the stamens and calyxes, followed by that in the pistils and receptacles, and the lowest in the petals and stalks. These results suggest that RrAADC and RrPAR coordinately regulate the biological synthesis of 2-phenylethanol in R. rugosa.     

Permanent stigma closure in Bignoniaceae: Mechanism and implications for fruit set in self-incompatible species

The Bignoniaceae possess sensitive bilobate stigmas that close after stimulation. We determined factors involved in stigma closure and reopening in four species of Bignoniaceae from the National Parks of Catimbau, Northeastern Brazil (Anemopaegma laeve, Arrabidaea limae, Jacaranda rugosa and Tabebuia impetiginosa). The study showed that any mechanical touch promoted the stigmatic closure. Only the deposition of viable con-specific pollen (self- and cross-pollen), however, maintained stigmas permanently closed. In Arrabidaea limae part of the stigmas reopened after self- and cross-pollination. After mechanical stimulation, deposition of pollen from other plant species, of dead con-specific pollen or of sand, the stigma lobes opened again after 38 to 68 min. The definitive closure may have a negative effect on the reproductive success of the involved plants, because the stigmas are permanently unavailable for pollen deposition. In self-incompatible species with mass-flowering blooming pattern, where pollinators promote high levels of geitonogamy, definitive stigma closure causes low fruit set.     

Chemical cues involved in the attraction of the oligolectic bee Hoplitis adunca to its host plant Echium vulgare

Host recognition is a key process in oligolectic bees but the mechanisms through which they find and recognize appropriate pollen host plant are not entirely clear. Hoplitis adunca is a monolectic bee collecting pollen only from Echium spp. (Boraginaceae). We aimed to test whether Echium vulgare floral scent plays a major role in the attraction of H. adunca females, and to identify components of E. vulgare scent that may be involved in this specific attraction. We used a combination of behavioral and chemical (GC/GC–MS, PTR-MS) analyses. In order to identify the chemical cues likely to be involved in the specific attraction of H. adunca, we compared the scent of fresh flowers, nectar, pollen, and whole plants of E. vulgare and Anchusa officinalis, another Boraginaceae, which does not attract H. adunca. H. adunca females were attracted to the scent of E. vulgare flowers when offered against a blank or against the scent of A. officinalis flowers. However, H. adunca females were not attracted to the scent of A. officinalis flowers when offered against a blank. The emission spectra of the two plant species differed markedly, as did the emission spectra of various flower components (pollen, nectar and whole flowers) within a species. Pollen presented a low volatile release, but emitted significantly higher amounts of mass 55 (butanal, 1,3-butadiene, or other volatiles of molecular mass 54), and mass 83 (hexanal, hexenols, hexenyl acetate, or other volatiles of molecular mass 82) in E. vulgare than in A. officinalis. Nectar produced a particular emission spectrum with high emission rates of masses 109 and 123. Mass 109 may likely correspond to 1,4-benzoquinone, a volatile specifically measured in E. vulgare in parallel studies to this one. The flower emission spectrum was mainly a combination of the pollen and the nectar scents, although it also contained additional volatile compounds such as those of mass 63 or mass 81. As for terpenes, E. vulgare emitted limonene, longicyclene, junipene, trans-caryophyllene and α-humulene, that were not detected in A. officinalis, and the most emitted monoterpenes were α-pinene, junipene and limonene whereas the most emitted terpenoid by A. officinalis was α-pinene. After identifying these chemical cues, olfactory/behavioural assays with specific volatiles and combinations of volatiles are necessary to understand the chemical interactions of the H. adunca-E. vulgare system.     

Systematic importance of pollen morphological features of selected species from the genus Rosa (Rosaceae)

The aim of this study is verification of the taxonomic usefulness of the pollen grain features studied, based on pollen morphology of 32 wild species from all 4 subgenera and all 10 sections of the genus Rosa, mainly for delimitation of subgenera, sections, and species. The measurements and observations were carried out with both light microscopy and scanning electron microscopy. Only correctly formed pollen grains (30 per specimen) were measured, and 960 pollen grains were examined in total. They were analyzed for 14 quantitative features of pollen grains and exine sculpturing and the following qualitative ones: outline, shape, and operculum structure. Our study revealed that the diagnostic features of pollen grains studied were: exine sculpture, length of polar axis, and pollen shape (P/E ratio). On the basis of the above characters, five species were isolated and the remaining ones were included in several groups isolated on the basis of exine sculpture types. The following three exine sculpture types occurred in the species studied: granular-verrucate (in R.?stellata), striate-psilate (in R.?multibracteata and R.?multiflora), and striate (the remaining species). R.?banksiae is characterized by small pollen grains, while R.?setigera has strongly elongated pollen with P/E ratio >1.5. Exine sculpture features considered to be diagnostic should be treated as auxiliary because they fail to differentiate individual species, although they can be helpful in distinguishing groups of species of similar exine sculpture. The arrangement of the species examined on a dendrogram only slightly corroborates division of the Rosa genus into subgenera and sections currently adopted in taxonomy (Rehder 1940). An interesting result was reported for the species studied from the Caninae (R.?agrestis, R.?canina, R.?dumalis, R.?jundzillii, and R.?rubiginosa) section which, despite hybrid nature, with the exception of R.?villosa, grouped in the same, most separated group of species.     

玫瑰种群生物学研究进展

玫瑰(Rosa rugosa Thunb.)原产于我国东部沿海、日本、朝鲜半岛和俄罗斯远东地区,18世纪作为园艺种引入欧洲后逃逸并入侵至北海和波罗的海周边多个国家以及北美沙质海岸,而中国野生种群却在过去30年间持续萎缩,成为珍稀濒危物种。从玫瑰种群生物学角度,通过文献比较和综合,在阐明玫瑰生态学特性和野生分布变化的基础上,全面论述了玫瑰种群在我国的生境退化、种群动态、种子繁殖、遗传多样性、濒危机理、保育方面的成果和悬疑问题;并结合欧洲入侵种群分布范围和敏感生境、对本地群落和物种的影响、种子繁殖、遗传变异、种群扩张和模拟预测、管理和控制方面的研究进展,分析了濒危种群和入侵种群数量动态、群落组成、幼苗更新、遗传变异、管理策略方面的差异及其影响因素;进而提出未来的玫瑰研究可从濒危种群和入侵种群的比较研究、种群和灌丛的动态监测、适合度相关性状的变异及其遗传基础、基于种群生物学的保育或控制4个方面为切入点,集中探索玫瑰种群濒危和入侵动态的规律、遗传基础和主要驱动力,为玫瑰保育和管理提供理论依据,为相似物种的适应和进化机制研究提供例证。     

Involvement of Androgen Receptor in Sex Determination in an Amphibian Species

In mice and humans, the androgen receptor (AR) gene, located on the X chromosome, is not known to be involved in sex determination. In the Japanese frog Rana rugosa the AR is located on the sex chromosomes (X, Y, Z and W). Phylogenetic analysis shows that the AR on the X chromosome (X-AR) of the Korean R. rugosa is basal and segregates into two clusters: one containing W-AR of Japanese R. rugosa, the other containing Y-AR. AR expression is twice as high in ZZ (male) compared to ZW (female) embryos in which the W-AR is barely expressed. Higher AR-expression may be associated with male sex determination in this species. To examine whether the Z-AR is involved in sex determination in R. rugosa, we produced transgenic (Tg) frogs carrying an exogenous Z-AR. Analysis of ZW Tg frogs revealed development of masculinized gonads or ‘ovotestes’. Expression of CYP17 and Dmrt1, genes known to be activated during normal male gonadal development, were up-regulated in the ZW ovotestis. Testosterone, supplied to the rearing water, completed the female-to-male sex-reversal in the AR-Tg ZW frogs. Here we report that Z-AR is involved in male sex-determination in an amphibian species.     

Shared pollinators and pollen transfer dynamics in two hybridizing species, Rhinanthus minor and R. angustifolius

Gene flow between hybridizing plant species depends strongly on pollinator behaviour, which affects pollen transfer among floral types and reproductive isolation. We examined bumblebee behaviour and pollen transfer between two hybridizing Rhinanthus species that are very similar in ecology and floral traits. The two species, Rhinanthus minor and R. angustifolius, shared similar pollinator guilds and assemblages, but pollinator recruitment and flower visitation rates were higher in R. angustifolius sites, probably because of its higher reward levels and better visibility. When presented with Rhinanthus flowers, bumblebees that previously foraged on R. angustifolius were less prone to visit R. minor inflorescences, while R. minor foragers accepted both species in similar proportions. Although Rhinanthus has been cited as a case of mechanical isolation resulting from interactions between bee behaviour and differences in stigma and anther placement, we found no support for efficient mechanical reproductive isolation. Bumblebees that foraged on R. minor flowers carried more pollen, but pollen placement on their bodies was similar to that of bees that visited R. angustifolius, and cross-specific stigmatic pollen deposition was similar in both directions. However, the asymmetry in pollinator handling time between the two species, due to dissimilar pollen rewards, may have lowered relative heterospecific pollen receipt on R. angustifolius, suggesting that net gene flow resulting from pollen transfer dynamics is more likely towards R. minor, although this effect remains weak and will be most likely counterbalanced by context-based labile pollinator preference.     

Pollen tube reallocation in two preanthesis cleistogamous species, Ranalisma rostratum and Sagittaria guyanensis ssp. lappula (Alismataceae)

Pollen deposition on stigmas and pollen tube growth in two apocarpous species, Ranalisma rostratum and Sagittaria guyanensis ssp. lappula (Alismataceae), were examined with fluorescence microscopy. The reallocation of pollen tubes among pistils was observed in both species. The percentage of pollinated stigmas per flower was only 22.0% in R. rostratum and 51.0% in S. guyanensis, though the seed/ovule ratios are higher than 65% in both species. The number of pollen grains on each single stigma ranged from 0 to 96 in R. rostratum, and from 0 to 125 in S. guyanensis. When more than one pollen grain deposited on a stigma, all pollen tubes grew to the ovary, but only one of them turned towards the ovule and finally entered the nucleus. The other tubes grew through the receptacle tissue into ovules of adjacent carpels whose stigmas were unpollinated or pollinated later. The intercarpellary growth of pollen tubes could be a mechanism to increase the efficiency of sexual reproduction in an apocarpous gynoecium with low pollination on the pistils.     

机械损伤对重瓣玫瑰防御酶的诱导

为研究重瓣玫瑰（Rosa rugosa ‘plena’）的诱导抗虫性,采用机械损伤方式诱导处理重瓣玫瑰,研究机械损伤对重瓣玫瑰叶片防御酶活性的影响。结果表明,机械损伤可诱导重瓣玫瑰叶片苯丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)、过氧化物酶(POD)活性的增加,PPO、POD活性先升高后下降,PAL活性的升高持续时间较长。T3（打孔损伤,3孔/叶）处理为最适的损伤程度,诱导的PAL、PPO、POD活性分别在第7、3、5天达到最高值。因此认为,采用适度地损伤能够诱导重瓣玫瑰较高的防御酶活性,提高植株的防御能力。     

Effect of calcium and sucrose concentration on pollen germination invitro of sixRosa species

The germination of the pollen from11 individuals of six wildRosa species was studied. The presence of calcium resulted in increased pollen germination, longer pollen tubes, and in a decrease of the requirement of sucrose concentration in cultivation media. Pollen germination in the medium with Ca reached the values of pollen viability estimated by tetrazolium test in all cases except with roses with balanced heterogamy, of the sectionCaninae. The stimulating effect of calcium was generally most pronounced in the pollen from roses of hybrid nature, such asR. jundzillii, R. canina, and especially in the case of the calciphilous speciesR. eglanteria.