Annual Flowering Plant Research Articles

萌芽菊芋块茎对盐碱土壤胁迫的生理响应

PDF HTML阅读 XML下载 导出引用 引用提醒 萌芽菊芋块茎对盐碱土壤胁迫的生理响应 DOI: 10.5846/stxb201610262181 作者: 作者单位: 东北林业大学,东北林业大学盐碱地生物资源环境研究中心,东北林业大学,东北林业大学盐碱地生物资源环境研究中心 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31470467） Physiological response of sprouting Jerusalem artichoke tubers to saline-alkali stress Author: Affiliation: Northeast Forestry University,,Northeast Forestry University,Alkali Soil Natural Environmental Science Center,Northeast Forestry University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:土壤盐碱化是影响全球农业生产和生态环境的重要问题。在农田、轻度盐碱草地和重度盐碱草地设置样地以块茎种植菊芋，次年5月块茎萌发阶段取块茎样品测定丙二醛、游离脯氨酸、可溶性糖含量以及抗氧化酶活性并进行蛋白质组学分析，分析了萌芽菊芋块茎对盐碱土壤胁迫的生理响应。0-20 cm土层的电导率（表征土壤可溶盐含量）表明从农田到轻度、重度盐碱草地土壤盐碱胁迫逐渐增强，丙二醛含量变化反映出菊芋块茎受害程度逐渐增加，并且基于游离脯氨酸的渗透调节能力也在逐渐增强。蛋白质组学分析结果显示与遗传信息加工相关的差异蛋白数量最多（占28.75%）且多为表达上调，意味着DNA复制和转录、蛋白质合成和折叠的相关蛋白在响应盐碱胁迫中发挥关键作用。碳水化合物及多糖代谢（占15%）、氨基酸代谢（占11.25%）以及能量代谢（占7.5%）相关的差异蛋白数量也较多，说明调节物质代谢平衡在萌芽菊芋块茎应对盐碱土壤胁迫过程中有重要作用。这些结果为揭示萌芽菊芋块茎适应盐胁迫的生理机制奠定了基础。 Abstract:Soil salinization is one of the most common abiotic stresses affecting plant growth and is becoming an important issue, owing to its impact on agricultural production and the environment. Saline-alkali soil is becoming particularly widespread and may cover more than 50% of all arable lands by the year 2050. The combination of soil salinization and high pH conditions represents a major impediment for plant growth and crop productivity. The study area was a typical alkalinized grassland in northeastern China. Jerusalem artichoke (Helianthus tuberosus) is an annual flowering plant that has been cultivated as a vegetable, fodder crop, and bioenergy material in many countries, owing to its high levels of polysaccharides, especially inulin. The ability to survive in the saline-alkali soils of semiarid areas is one of the most important characters of Jerusalem artichoke. Jerusalem artichoke tubers were sown in farmland, light saline-alkali, or severe saline-alkali soil and sprouting tubers were collected from the sample in May of the following year. The malondialdehyde, free proline, and soluble sugar contents, antioxidant enzyme activity, and protein profile were quantified, in order to assess the physiological response of Jerusalem artichoke to saline-alkali stress. The soil electrical conductivity (0-20 cm) indicated that the soluble salt contents of the three soil types were significantly different, with the lowest soluble salt content in the farmland soil and the greatest content in the severe saline-alkali soil. With increasing soluble salt content, the malondialdehyde content increased, obviously indicating higher levels of stress, and increased free proline content indicated that Jerusalem artichoke could enhance its resistance to salt stress via osmotic adjustment. To investigate the proteomic response of the sprouting tubers to saline-alkali stress, two-dimensional gel electrophoresis (2-DE) gels from three biological experiments were analyzed. Then, using ImageMaster 2D Platinum Software, we identified more than 1000 highly reproducible protein spots on the coomassie brilliant blue (CBB)-stained 2D gels. A total of 80 differentially expressed proteins were successfully identified using MALDI-TOF/TOF analysis, according to the peptide matching results provided by MASCOT. Among these proteins, 42 were detected in the sprouting H. tuberosus tubers from the light saline-alkali soil and 38 of the proteins accumulated differentially in the tubers grown in the severe saline-alkali soil. KEGG pathway analysis attributed these proteins to eleven different metabolic pathways, which included carbohydrate and polysaccharide metabolism (15%), energy metabolism (7.5%), genetic information processing (28.75%), amino acid metabolism (11.25%), nucleotide metabolism (2.5%), biosynthesis of secondary metabolites (3.75%), signal transduction (17.5%), transport and catabolism (2.5%), cell motility (2.5%), and unknown (8.75%). The differentially expressed proteins were mainly involved in genetic information processing, which might indicate that the regulation of proteins involved in DNA replication, transcription, protein synthesis, and protein folding are responsive to saline-alkali stress and play a pivotal role in salinity tolerance. Carbohydrate, energy, and amino acid metabolism-related proteins constituted one-third of the differentially expressed proteins, which suggests that metabolism homeostasis is important for the survival of seedlings exposed to saline-alkali stress. These findings provide new insight into the underlying molecular mechanisms of saline-alkali resistance in Jerusalem artichoke. 参考文献 相似文献 引证文献

Nigella sativa – A Functional Spice From A Pharaoh’s Tomb to Modern Healthcare

Black cumin, Nigella sativa (NS), which is also known as black seed (Kalijeera), is an annual flowering plant from the Ranunculaceae family. Its seeds were used in most ancient medical systems. For ages it was considered to be a panacea. It is rooted in our traditions and has flourished into an intensively investigated medicinal plant. There is an abundance of reports on the biological activities of Nigella sativa seeds or extracts. The spectrum of its activity is impressive and includes antimicrobial, antiviral, anticancer, antimalarial as well as an antidiabetic or immunostimulatory potency. In this review both in vitro and in vivo results are gathered and the results of clinical trials are discussed. Patents and the industrial use of NS as both a food supplement and as animal feed are also mentioned. An analysis of the literature data showed that the comprehensive investigations of Nigella sativa are fairly well translated into actual everyday healthcare. The data presented in this review reveals future use of this valuable plant.

Geographical distribution of the genus Alternaria Nees on annual flower and ornamental plants

Geographical distribution of the genus Alternaria Nees on annual flower and ornamental plants

An Overview of Products and Bias in Research.

Cannabis is a genus of annual flowering plant. Cannabis is often divided into 3 species-Cannabis sativa, Cannabis indica, and Cannabis ruderalis-but there is significant disagreement about this, and some consider them subspecies of the same parent species. Cannabis sativa can grow to 5-18 feet or more, and often has a few branches. Cannabis indica typically grows 2-4 feet tall and is compactly branched. Cannabis ruderalis contains very low levels of Δ-9-tetrahyocannabinol so is rarely grown by itself. Cannabis ruderalis flowers as a result of age, not light conditions, which is called autoflowering. It is principally used in hybrids, to enable the hybrid to have the autoflowering property. There are > 700 strains of cannabis, often with colorful names. Some are strains of 1 of the 3 subspecies. Many are crossbred hybrids. The strains can be named in a variety of ways: smell or lineage are common ways of naming. There are only a few rules about how the strains are named, and most strains' names do not follow the rules. There are 4 basic preparations of marijuana: bhang, hasish, oil (or hash oil), and leaves and/or buds. In medical marijuana trials, subjective outcomes are frequently used but blind breaking can introduce significant bias. Blind breaking occurs when patients figure out if they are in the control or the treatment group. When this occurs, there is significant overestimation of treatment effect.

Consumer Preferences for Traditional, Neonicotinoid-free, Bee-friendly, or Biological Control Pest Management Practices on Floriculture Crops

Neonicotinoids have recently been implicated by the media as a contributing factor to the decline of honey and bumblebees. We sought to better understand consumer perceptions and willingness to pay for traditional, neonicotinoid-free, bee-friendly, or biological control pest management practices as growers may seek alternative management practices to systemetic insecticides. We conducted a nationwide Internet survey (n = 3082), where consumers answered attitudinal, comprehension, likelihood-to-buy, and demographical questions about indoor (marketed in 10-cm pots) and outdoor (marketed in 30-cm hanging baskets or 10-cm pots) floriculture products. The likelihood-to-buy questions were analyzed using conjoint analysis to determine which attributes had the greatest part-worth scores or which ones were viewed most positively by survey respondents. Of the total participants, 65.1% (n = 2002) of the subjects had purchased an annual flowering plant in the 12 months before the survey. Respondents reported that the most important plant health and appearance factors that affect their purchasing decisions were that the flowering plants have no plant damage, while the second most important factor was that plants have no insects on them. The least important factor in the ranking of stated importance was that no neonicotinoid insecticides were used during the production of the plant. This finding may have resulted from 56.6% of all participants who reported that they did not understand the term. For those who viewed the indoor 10-cm flowering plants (n = 1052), the plant species accounted for 41.2% of the decision to purchase the plant, followed by production type (32.8%) and price (26.0%). All three product attributes were of equal importance to the subjects who viewed the outdoor 10-cm flowering plants (n = 1024), whereas only price had a lower relative importance when compared with production type and species for those who viewed the 30-cm hanging baskets (n = 1006). Across all three studies, use of the term “bee-friendly” had the greatest economic value because it had the highest part-worth utility score, or the greatest willingness-to-buy. For the subjects who viewed the outdoor plants, “bee-friendly” and “use of beneficial insects” had greater economic value (with positive part-worth utility scores), but “neonicotinoid-free” and “traditional insect control” both had negative part-worth utility scores, indicating they were valued less and detracted from the dollar value of the plant. The term “bee-friendly” was worth up to five times more to those respondents that had bought a plant in the last 12 months compared with those who had not. Therefore, if ornamental plants are labeled with pest management practices, most consumers value the term “bee-friendly” more and will likely discount products labeled “neonicotinoid-free.”

The Current State and Prospects of Perennial and Annual Flower Plants Selective Breeding and Introduction Development

The Current State and Prospects of Perennial and Annual Flower Plants Selective Breeding and Introduction Development

First Report of Downy Mildew Caused by Hyaloperonospora camelinae on Camelina sativa in Slovenia.

Camelina or false flax (Camelina sativa), of the Brassicaceae, is an annual flowering plant native to Europe and Central Asia where it is grown commercially as an oilseed crop. At the end of May 2012, symptoms of downy mildew were observed on camelina plants grown in the Savinja Valley in Slovenia. The disease was found in four monitored fields (total area 3 ha), and the incidence ranged from 2 to 38% depending on the variety. Symptomatic plants showed whitish, abundant, and fluffy mycelia covering the stems, flowers, seed pods, and undersides of the leaves. The disease mainly affected the upper half of the plants, and the stems were reduced and distorted. During disease progression, the mycelium turned from gray to black. Microscopic observations revealed hyaline, straight conidiophores that were branched monopodially (3 to 4 times) with 6 to 12 re-curved tips/branch, and measured 140 to 300 × 12 to 20 μm. Conidia were hyaline, oval to broadly ellipsoidal, 24 to 29 × 18 to 24 μm. Oospores formed in necrotic stem and leaf tissues were dark brown and measured 30 to 38 μm in diameter. Based on these morphological characteristics, the causal agent was identified as Hyaloperonospora camelinae (1,3,4,5). DNA was extracted from mycelium and conidia collected from infected plants in two fields in the Savinja Valley (1HpC and 2HpC). Nuclear internal transcribed spacer (ITS) regions of ribosomal DNA (rDNA) were amplified by PCR assay from two isolates using the universal primers ITS4 and ITS5, and sequenced. Both samples yielded a 781-bp sequence, which showed 100% identity to H. camelinae ITS sequence JX445136 in GenBank. The nucleotide sequence was assigned to GenBank Accession No. KJ768405. Pathogenicity was confirmed by spraying 25 3-week-old plants of C. sativa cv. Ligena planted in pots (5 plants/pot) with a conidial suspension (105 conidia/ml) obtained from 10 infected plants of the same variety collected from the field 1HpC. Inoculated plants were covered with polyethylene bags for 2 days to maintain high humidity, and incubated at 20°C with a 12-h photoperiod/day in a growth chamber. Downy mildew symptoms first developed on leaves 6 days after inoculation. An additional 25 control plants sprayed with sterilized distilled water and otherwise treated similarly to the inoculated plants developed no symptoms. The identity of the pathogen on the inoculated plants as H. camelinae was confirmed based on the morphological features described above. Downy mildew of false flax caused by H. camelinae has been reported in Europe from Austria, Bulgaria, Germany, Poland, Portugal, Spain, and Switzerland (2); and in the United States from Florida, Oregon, Minnesota, Montana, Nebraska, and Washington (1,3,4,5). To the best of our knowledge, this is the first report of downy mildew caused by H. camelinae on C. sativa in Slovenia. The representative samples were deposited in the phytopatological herbarium of the Slovenian Institute of Hop Research and Brewing.

Characterization of Gypsophila species and commercial hybrids with nuclear whole-genome and cytoplasmic molecular markers

The genus Gypsophila contains about 150 annual and perennial flowering plant species native to the temperate regions of Europe and Asia. Nowadays Gypsophila species are present worldwide as garden ornamental plants. Although Gypsophila is one of the most economically important ornamental crops, little is known about its genetic variability and the relationships among the different wild species, cultivars, and commercial hybrids. The aim of our work was to analyze genetic distances among 5 wild species and 13 commercial hybrids of Gypsophila with similar phenotypes but unknown origin. For this purpose, we have used amplified fragment length polymorphism, target region amplification polymorphism, and inter simple sequence repeat whole-genome markers and chloroplast simple sequence repeat (cpSSR), targeting chloroplast DNA. Nuclear markers were found to distinguish all the analyzed samples while cpSSR markers were found to discriminate the different wild species, but could not sufficiently separate the commercial hybrids. This notwithstanding, the data obtained allowed us to cluster the commercial hybrids into different sub-groups and to determine the relationships with the putative species of origin.

Parasitic Beechdrops (Epifagus virginiana): A Possible Ant-Pollinated Plant

Abstract Epifagus virginiana (Beechdrop) is an annual flowering plant that parasitizes Fagus grandifolia (American Beech) roots. The pollination biology of the chasmogamous flowers of E. virginiana is unknown. In September 2011–2012, we observed insect visitors to E. virginiana flowers. Insect visitors included Bombus impatiens, Crematogaster spp., and Prenolepis imparis, but were dominated by P. imparis (over 96% of insect visits). In September 2012, we captured ants (Crematogaster and P. imparis) on E. virginiana flowers in three different areas found in the Coastal Plain and Piedmont physiographic provinces. With the use of 2,5-diphenyl tetrazolium bromide (MTT), we tested E. virginiana pollen from flowers and ant integuments for viability. We observed no significant difference (P > 0.05) between the viability of pollen taken directly from E. virginiana flowers and pollen removed from the ants. Our data suggests that ants can be playing an important role in the pollination of E. virginiana.

Evaluation of phytoremediation potential of Tagetes patula L. for the degradation of textile dye Reactive Blue 160 and assessment of the toxicity of degraded metabolites by cytogenotoxicity

Tagetes patula is an annual flowering plant belonging to family Asteraceae. The present study deals with in vitro decolorization and remediation of a textile dye Reactive Blue 160 by T. patula. There was considerable (∼90%) decolorization of the dye within 4d of incubation, as confirmed by UV–vis, HPLC and FTIR analysis. The enzymes responsible for the remediation were lignin peroxidase, tyrosinase, laccase and NADH–DCIP reductase which were found in root tissues of the plantlets. GC–MS analysis of the products revealed formation of six metabolites such as sodium benzenesulfonate, 6-chloro 1,3,5-triazine-2,4-diamine, disodium benzene-1,4-disulfonate, sodium 3-amino-4-hydroxybenzenesulfonate, 1-phenylmethanediamine and sodium 4-amino-3-carboxybenzenesulfonate after phytoremediation of Reactive Blue 160. Based on the FTIR and GC–MS results, the possible pathway for the biodegradation of Reactive Blue 160 has been traced. The non-toxic nature of the degraded products was confirmed by performing cytogenotoxicity tests on root tip cells of growing Allium cepa.

Flowers for better pest control? The effects of apple orchard ground cover management on green apple aphids (Aphis spp.) (Hemiptera: Aphididae), their predators and the canopy insect community

Effects of habitat diversification through ground cover management on green apple aphids (Aphis spp.) (Hemiptera: Aphididae), woolly apple aphid (Eriosoma lanigerum [Haussmann]) (Hemiptera: Aphididae), their insect natural enemies and the most abundant canopy insects (in the Neuroptera, Fulgoromorpha, Cicadomorpha, Heteroptera, Coleoptera and Formicidae) were studied in an apple orchard over 6 years. The composition and diversity of the main functional groups of canopy insects was also compared. Habitat diversification was achieved by changing ground cover conditions within the orchard. In the treatment termed FLOWER, annual and/or perennial flowering plants were sown in the alleys of an apple orchard. Other ground cover treatments were weed-free bare ground (termed BAREgr) and orchard plots with alleys of mowed grass (termed GRASS), which served as control treatments. We found no evidence that habitat diversification enhanced the biological control of green apple aphids compared to the control treatments. However, the greater plant cover in FLOWER resulted in increased woolly apple aphid infestations compared to BAREgr or GRASS. The abundance of various beneficial or neutral canopy insects – Chrysoperla carnea sensu lato (Neuroptera, Chrysopidae) adults, leafhoppers and treehoppers, planthoppers, herbivorous (non-apple feeding) beetles, dipterans and parasitoid wasps – also increased in FLOWER as compared to BAREgr, with GRASS being intermediate between the other treatments. Significantly greater species richness and diversity was found in FLOWER than in BAREgr for most of the functional groups sampled, although the number of predacious insect species was similar among treatments. The composition of the studied functional groups showed high similarity in FLOWER and GRASS, but these treatments were different from BAREgr. Effects of groundcover management on the dominant insect species are discussed.

Functional mapping of ontogeny in flowering plants

All organisms face the problem of how to perform a sequence of developmental changes and transitions during ontogeny. We revise functional mapping, a statistical model originally derived to map genes that determine developmental dynamics, to take into account the entire process of ontogenetic growth from embryo to adult and from the vegetative to reproductive phase. The revised model provides a framework that reconciles the genetic architecture of development at different stages and elucidates a comprehensive picture of the genetic control mechanisms of growth that change gradually from a simple to a more complex level. We use an annual flowering plant, as an example, to demonstrate our model by which to map genes and their interactions involved in embryo and postembryonic growth. The model provides a useful tool to study the genetic control of ontogenetic growth in flowering plants and any other organisms through proper modifications based on their biological characteristics.

Attractiveness of common insectary and harvestable floral resources to beneficial insects

Resources for natural enemies are often lacking in agricultural fields. The provisioning of floral resources in crop fields can ameliorate this problem by providing nectar and pollen to natural enemies. To select an appropriate floral resource, plants must be screened for their flowering times and attractiveness to natural enemies and pests. We tested the attractiveness of nine species of annual flowering plants to hoverflies, which are important predators of aphids in California lettuce fields. We also sampled arthropods in the foliage of tested plants, to assess the abundances of other natural enemy and pest species that were present. Tested plants included three commonly-used insectary plants and six flowering plant species that showed potential as either harvestable herbs or cut flowers. Harvestable insectary plants may provide additional economic incentive for growers to set aside land for floral resources. The commonly-used insectary plant sweet alyssum consistently attracted the most hoverflies and the least bees, while potentially harvestable plants attracted few hoverflies. Competition with bees may have reduced hoverfly visits to several of the tested plant species. Sweet alyssum also stayed in bloom the longest, and contained the highest numbers of predatory hemipterans. Results suggest that plants should be screened for their attractiveness to not only the target biological control agent, but also to other potential competitors for floral resources. While this initial study focused on a limited selection of harvestable annual plants, a wide variety of other marketable plant species, particularly perennials, remain to be tested for their attractiveness to hoverflies or other beneficial arthropods.

Protocols for in vitro cultures and secondary metabolite analysis of aromatic and medicinal plants

This book edited by S. Mohan Jain and Praveen K. Saxena covers a range of topics vital for the continued production of this essential but sometimes forgotten group of plants. Plants have always been an important part of traditional medicine; however, recently there has been increasing interest in and acceptance of using plant-based medicines. This has led to indiscriminate harvesting of wild species resulting in many species becoming endangered. This is a recurring theme in the book; micropropagation of endangered species, germplasm conservation, or using cell culture as an alternative to field cultivation for the aromatic and medicinal species. The book consists of 31 chapters, which are divided into five sections titled as follows: ‘Micropropagation and chemical analysis’, ‘Transgenic approaches’, ‘Molecular markers and microsatellites’, ‘Biotransformation, bioreactors and metabolomics’, and ‘Altered gravity and biotechnology’. The first section gives step-by-step procedures for propagating a number of medicinal plants that are endangered or hard to germinate. These chapters also cover the important bioactives found in the plants, the uses of these compounds, and protocols for biochemical analysis of the tissue-culture-derived plants. All chapters provide excellent notes on in vitro culture of the plants, the materials required, the media formulations, and the suppliers of the equipment or chemicals. The notes are in depth, with one example of field instructions reminding readers to ‘bring a raincoat’ and ‘understand risks from wild animals, spiders, insects or snakes’. The second section deals with transformation of medicinal and aromatic plants for the production of bioactive compounds and for basic research. Transformation via hairy root cultures, particle bombardment, and Agrobacterium tumefaciens-mediated transformation methodologies are provided as well as procedures for analysis of the transformants. The third section of the book deals with molecular markers and microsatellites. These two chapters deal with identification of medicinal plants by microarrays with MLPA (multiplexed ligase-dependent probe amplication) and microsatellites. Identification of the correct plant species is extremely important for medicinal plants, as wrong classification of a plant can have deadly results. The fourth section of the book focuses on biotransformation, bioreactors and metabolomics. A number of medicinal plants are very hard to grow or are slow growing, and therefore field cultivation is not the most desired system for producing the medicinally important bioactives. Developing cell cultures from these medicinal and aromatic plants and extracting the pharmaceutical compound is an alternative method to field production. Bioreactors allow for continuous extraction of the important bioactives from plant cell suspensions. This section also gives information on metabolomic analysis of cell cultures, a newer approach to survey all the metabolites in a plant. The last section looks at biotechnology for anti-cancer compounds and plant secondary metabolism under altered plant environments (altered gravity). These chapters are reviews and do not contain protocols but discuss results. The book takes us from micropropagating endangered plants for return to field conditions all the way to growing plants for long-term colonization of space. The methodology does not stop at the tissue culture stage, but goes on to include biochemical analysis of the plants for the important bioactive compounds. One of the benefits of this book is to have both aspects within one volume. The book covers a number of plant families (annual flowering plants, woody species, berries, tubers, water plants, orchids and bryophytes) that are grown in China, India, North America and Europe. These plants have bioactives that are beneficial for treatment of a range of diseases and ailments. The chapters are easy to read and the protocols are easy to follow. All the necessary information is within the chapter. Most of the chapters have pictures depicting the equipment, tissue cultures at different stages, or in vitro derived plants. Unfortunately, the pictures are all in black and white. I feel that it would have been beneficial to have some of the pictures in colour, especially the ones illustrating callus or suspension cultures. In conclusion, I would recommend this book to researchers and students working in the area of plant tissue culture and biochemical analysis. This book would also be beneficial as a text book or laboratory manual in plant tissue culture courses.

The influence of the environmental factors on some physiological processes at annual flower species

The culture of the annual flower plants presents some advantages: low price, simple culture, fast development and growth, a lively, bright colouring, various possibilities to use. We considered necessary to estimate the influence of the environmental factors on the evolution of some physiological processes at annual flower species, with various uses, in the conditions of the climatic changes. The biological material was represented by ten annual flower species. For this species, in the beginning of the blossoming, determinations on some physiological parameters in accordance with the climatic factors were made by using some non destructive methods. In this purpose the LC pro photosynthesis portable system was used. The following parameters were determined: the incident active radiation, the temperature in the leaf’s room, the stomatal conductance, the photosynthesis rate, the transpiration rate.

Temporal variation in the pollen:ovule ratios of Clarkia (Onagraceae) taxa with contrasting mating systems: field populations

Among plants, pairs of selfing vs. outcrossing sister taxa provide interesting systems in which to test predictions concerning the magnitude and direction of temporal changes in sex allocation. Although resource availability typically declines towards the end of the growing season for annual taxa, temporal changes in mating opportunities depend on mating system and should change less in selfing taxa. Consequently, given that the pollen:ovule (P:O) ratio of flowers reflects the investment in (and potential fitness pay-off due to) male vs. female function, we predicted that the P:O ratio should also be less variable among and within selfers than in closely related outcrossers. To test these predictions, we measured temporal changes in sex allocation in multiple field populations of two pairs of sister taxa in the annual flowering plant genus Clarkia (Onagraceae). In the outcrossing Clarkia unguiculata and the selfing Clarkia exilis, ovule production declined similarly from early to late buds, whereas pollen production remained constant or increased in the outcrosser but remained constant or decreased in the selfer. Consequently, the P:O ratio increased within unguiculata populations but marginally increased or stayed constant in exilis populations. In all populations of the selfing Clarkia xantiana spp. parviflora and the outcrossing C. x. spp. xantiana, both ovule and pollen production per flower declined over time. The effects of these declines on the P:O ratio, however, differed between subspecies. In each xantiana population, the mean P:O ratio did not differ between early and late flowers, although individuals varied greatly in the direction and magnitude of phenotypic change. By contrast, parviflora populations differed in the mean direction of temporal change in the P:O ratio. We found little evidence to support our initial predictions that the P:O ratio of the selfing taxa will consistently vary less than in outcrossing taxa.

Food for insect pollinators on farmland: insect visits to flowers of annual seed mixtures

Intensification of agriculture in recent decades has impoverished farmland for insect pollinators by removing their food plants. Arable farmland can be enhanced as a habitat for these insects by growing annual nectar- and pollen-producing herbaceous plants for them in non-cropped areas such as set-aside and field margins. In 1996 and 1997, observations were made in Hertfordshire, UK, on the flowering phenology and flower-attractiveness to visiting Hymenoptera, Diptera and Lepidoptera of plots sown to mixtures of six annual flowering plant species: borage (Borago officinalis), buckwheat (Fagopyrum esculentum), cornflower (Centaurea cyanus), mallow (Malva sylvestris), marigold (Calendula officinalis) and phacelia (Phacelia tanacetifolia) in different proportions. The mixtures had good agronomic and biological properties. They established and flowered well from a range of seed rates and sowing-dates. They attracted a diversity of flower-visiting insects, including the honey bee and eightspecies of bumble bee amongst 16 species of aculeate Hymenoptera, 17 species of Diptera, mostly syrphids, and six species of Lepidoptera. Sequential sowings provided nectar and pollen from early summer to late autumn during the period after arable crops had finished flowering and food for pollinators was scarce. Different insect species were favoured by different sowing-dates and plant species

Effects of simulated herbivory on growth and reproduction of two beach annuals, Cakile edentula and Corispermum hyssopifolium

Cakile edentula var. lucustris (sea rocket) and Corispermum hyssopifolium (bugseed) are two annual flowering plants that grow on the sandy shores of the Great Lakes. This habitat is extremely unpredictable and plants are subject to grazing by a number of insect herbivores as well as browsing by white-tailed deer. The objectives of these studies were to estimate the extent of herbivore damage under natural conditions, to determine the most vulnerable stage of damage, and to examine the compensatory ability of each species to tolerate herbivory. Greenhouse experiments showed that both species were able to compensate for low to moderate levels of artificial defoliation. However, high levels near the time of anthesis reduced the growth and reproductive output of both species. Similar experiments in the field revealed that although the critical time of damage was still the same, the plants were less able to tolerate herbivory. Cakile edentula plants exposed to natural herbivory in an unsprayed cabbage field were quickly attacked by large numbers of specialist insect herbivores and completely defoliated in 11 days. The fact that such damage does not occur in its natural habitat suggests that Cakile edentula escapes heavy damage because insects are unable to locate these populations along the shoreline. Key words: white-tailed deer, defoliation intensity, defoliation stage, compensatory response, indeterminate growth.

The habitat of Lythrum hyssopifolia L. in cambridgeshire, its only surviving English locality

Lythrum hyssopifolia, always a scarce species in the British Isles, is now confined to Cambridgeshire and to Jersey, Channel Islands. In Cambridgeshire it is restricted to an area of 10 km 2, where it occurs locally in shallow depressions in arable fields, consistently associated with Bryum klinggraeffii, Juncus bufonius, Plantago major ssp. intermedia and Polygonum persicaria. it is dependent on both winter flooding and the regular ploughing of these sites for its survival. The vegetation in which it is found is referable to the Isoeto-Nanojuncetea, largely composed of annual flowering plants and ephemeral bryophytes. Lythrum and its most frequent associates share: (1) the ability to germinate in spring; (2) the lack of long-term competitive ability; (3) a similar floral biology, being predominantly self-pollinated; and (4) potentially long-lived seeds. Two groups of bryophytes grow with Lythrum, monoecious species reproducing sexually and dioecious species reproducing vegetatively by rhizoid-tubers.

Toxicity of Dibrom Vapors to Greenhouse Insects1

The application of liquid concentrates containing Dibrom® (1,2-dibromo-2,2-diehloroethyl dimethyl phosphate) to heating pipes in greenhouses resulted in good control of greenhouse white fly ( Trialeurodes raporariorum (Westwood)), potato aphid ( Maerosiphum enphorbiae (Thomas)), two-spotted spider mite ( Tetranychus telarius (L.)), and other pests on bearing tomatoes. Good control or green peach aphid ( Myzus persicae (Sulzer)) on several types of vegetable and annual flowering plants was also obtained. Mushroom mite ( Tyrophayus putrescentiae (Schrank)) was not satisfactorily controlled by Dibrom vapor treatments. Dibrom vapor treatments killed insects and mites in all parts of the greenhouse with no lingering residue problems.