Winter Flowering Research Articles

バラ養液栽培における多孔質セラミックス培地の粒径と給液量が切り花の収量・品質に及ぼす影響

To test porous ceramic ball (PCB) as a new substrate for soilless culture of roses, the influence of particle size and fertigation quantity on the yield and quality of cut roses cv. Rote-rose was investigated using rockwool (RW) as a control. The solid phase distribution in three phases of PCB was a little less than 40 %, without regard to the particle size. The liquid phase distribution was directly proportional to the particle size so that the smaller the particle size, the larger the liquid phase ; for particle size ranging from 0.5a1.5 (mm/φ) it was 47%. Phosphoric acid was less concentrated in the exhaust fluid of PCB than it was in the nutrient solution. A decrease in PCB particle size increased the water capacity of the substrate which resulted in heavier cut flower fresh weights and longer stems, but a smaller percentage of dry matter. Increasing the amount of fertigation had a more positive influence on cut flower fresh weight, stem length, and leaf area than did the increase in water capacity of the substrate. However, neither the water capacity of the substrate nor the fertigation quantity had little influence on the yield of cut flower. Compared to PCB particles, when RW was used for substrate, both the quantity and quality of the cut flowers were decreased. Moreover, the vase life of cut flower grown on RW was shorter than that on PCB. It was concluded that the optimum particle size of PCB for soilless culture of roses ranged from 0.5 to 4.5 (mm/φ). With this substrate setted approximately 2.5 liter/plant, the amount of fertigation for each rose plant per day estimated 900 ml during the summer and 450 ml in winter. When the waterlogging was combined, decreasing the amount of fertigating by half of standard did not cause any ill-effect on the quality of cut flower in autumn and winter so the practice was considered to be effective.

HURRICANE CAUSES RESOURCE AND POLLINATION LIMITATION OF FRUIT SET IN A BIRD-POLLINATED SHRUB

Hurricanes can strip leaves from plants and provide other stresses that can reduce resource availability for subsequent reproduction. In addition, hurricanes commonly reduce populations of bird pollinators. I measured both resource and pollination limitation of fruit set for Bahama Swamp-bush (Pavonia bahamensis) on San Salvador Island in the Bahamas before and after two seasons of hurricanes. Before the hurricanes in the winter flowering season in 1994–1995, fruit set of P. bahamensis was 100% for most shrubs. After a mild hurricane, in 1995–1996, fruit set was 48%. After the severe Hurricane Lili (Category 2) in 1996–1997, mean fruit set was only 11%. In both years after the hurricanes, lower fruit set reflected resource limitation. In 1996–1997 after Hurricane Lili, fruit set was severely reduced an additional 74% by pollination limitation. Pollination limitation was caused by declines of the two bird pollinators, Bananaquits and Bahama Woodstars. In 1994–1995, both species were frequent visitors to fl...

Hurricane Causes Resource and Pollination Limitation of Fruit Set in a Bird-Pollinated Shrub

Hurricanes can strip leaves from plants and provide other stresses that can reduce resource availability for subsequent reproduction. In addition, hurricanes commonly reduce populations of bird pollinators. I measured both resource and pollination limitation of fruit set for Bahama Swamp-bush (Pavonia bahamensis) on San Salvador Island in the Bahamas before and after two seasons of hurricanes. Before the hurricanes in the winter flowering season in 1994–1995, fruit set of P. bahamensis was 100% for most shrubs. After a mild hurricane, in 1995–1996, fruit set was 48%. After the severe Hurricane Lili (Category 2) in 1996–1997, mean fruit set was only 11%. In both years after the hurricanes, lower fruit set reflected resource limitation. In 1996–1997 after Hurricane Lili, fruit set was severely reduced an additional 74% by pollination limitation. Pollination limitation was caused by declines of the two bird pollinators, Bananaquits and Bahama Woodstars. In 1994–1995, both species were frequent visitors to flowers, but in 1996–1997 these birds were rarely seen on the island. A concurrent mist-netting study indicated that Bananaquit populations were decimated after Hurricane Lili in 1996. Nectar removal was virtually absent, and pollen deposition on stigmas was low. In 1994–1995, 98% of the stigmas had received pollen by the end of floral life. In contrast, in 1996–1997, 51% of the flowers had received no pollen, supporting the conclusion that pollination limitation of fruit set was strong. There was no compensatory pollination by other pollinators, either other bird species or insects. These results indicate that severe hurricanes can affect fruit set directly through resource limitation and indirectly through reducing bird pollinators and causing pollination limitation of fruit set. Reduced fruit set after a hurricane could be especially disadvantageous because hurricanes can create sites for plant recruitment. Although resource limitation of fruit set may affect many plant species, bird-pollinated species may be faced with a double jeopardy of resource limitation of fruit set and pollination limitation of fruit set. Whether this disadvantage affects the recruitment of bird-pollinated plants after hurricanes or their adaptations for recruiting after hurricanes remains to be examined.

Fenologia de uma comunidade de duna frontal no sul do Brasil

Este estudo visou descrever os padrões fenológicos em uma comunidade de dunas costeiras em Santa Catarina (27ºS), avaliar suas relações a fatores climáticos e comparar estes padrões aos de comunidades situadas em outras latitudes na costa brasileira. O estudo foi realizado com espécies da duna frontal da Praia da Joaquina, Ilha de Santa Catarina, SC. Empregou-se um método com base em freqüência, calculando-se mensalmente a ocorrência das espécies e de suas fenofases (n=73 quadrados fixos de 1x1m). Ocorreram espécies florescendo e frutificando ao longo de todo o ano. como observado nas comunidades situadas a menores latitudes (SP: 24ºS e ES: 20ºS). O maior número de espécies em floração e frutificação ocorreu no período quente e super-úmido. De forma distinta ao que ocorre no extremo sul do Brasil (RS: 32ºS), observaram-se várias espécies em floração nos meses mais frios de inverno. Muitas destas, entretanto, com floração longa, mostraram redução em suas amplitudes de floração neste período. Isto pode sugerir certa limitação por temperaturas mais baixas e/ou refletir o déficit hídrico ocorrido neste período. Das 34 espécies monitoradas, 15 mostraram episódios de germinação, sendo estes mais freqüentes em meses de outono/inverno, com temperatura e umidade em declínio. A germinação no outono/inverno é discutida como estratégia utilizada pelas espécies de duna como forma de escapar das condições de maior temperatura e evapotranspiração no verão. Processos de rebrota foram registrados para 17 espécies, sendo também mais freqüentes no período do outono/inverno. Restrições de umidade com ocorrência de déficit hídrico afetam tanto os eventos de floração e frutificação, como os de germinação e brotamento.

Sending Flowers to the Moon: Notes on Flowers and Writing

Short, delicate, heady breaths. I disappear into the bouquet on my desk of white flowers—white flowers in winter, white flowers longing to become snow. All the other memory-short senses are utterly, magnificently dreary beside this one. And yet, the language of flowers is woeful—their fragrant gestures are feeble; no sooner are they uttered than they droop and Still, the old, elusive language of flowers is more accurate than our own. * Knowledge. What do we know that a flower cannot say? What does a flower know that we cannot? What has not been said about flowers, said with flowers? Every rose knows roses, speaks of past roses, quotations spelled out in red, pink, yellow dust. What does the muse know of flowers? In a poem called Envoi, Eavan Boland writes: The winter-flowering jasmine casts a shadow outside my window in my neighbor's garden. These are the things that my muse must know. Perhaps the muse, a woman's muse, is a small and plain, speckled bird. Or, maybe, a bumblebee. Attracted by bowls of sugar water, pots of geraniums left on desks, trompe-l'oeil paintings of intricate bouquets. * Necessity. On my desk, small pink roses...When I am alone the flowers are really seen; I can pay attention to them. They are felt as presences. Without them I would die. (May Sarton). The writer has a room of her own, she has food in her belly. Now she needs bunches of flowers in her rooms. Flowers decorating the stanzas of her poems. Vines growing up over the windows, It's a tangled world of vines, syllables, honeysuckle, colors, and words... (Clarice Lispector). Flowers on top of words on top of flowers. They perish and perish. Are renewed. A flower moves through time, because we crave something beautiful, alive. Because beauty isn't just one thing. We watch flowers bloom and peak, and wither and wilt and brown and droop and sag, lose petals and decay. Watching them perish, we learn how to live, which is the same as learning to write. Sending Flowers to the Moon: Notes on Flowers and Writing http://www.langandlit.ualberta.ca/archives/vol11papers/flowers.htm

First Report of Tobacco Streak Ilarvirus from Honeysuckle.

A honeysuckle (Lonicera fragrantissima) shrub on the grounds of the former Plant Quarantine Station, Glenn Dale, MD, had chlorotic leaves on some shoot tips and a mild veinal chlorosis. Young leaves were triturated in buffer and rub-inoculated onto a series of potential indicator hosts. The virus incited necrotic local lesions and necrosis of the growing point in Chenopodium quinoa, etched ringspots on inoculated leaves of Nicotiana tabacum Xanthi nc, mosaic in Zinnia violacea, and chlorotic local lesions in Tetragonia tetragonioides. It did not infect any of 46 other herbaceous genera in families Cucurbitaceae, Fabaceae, Asteraceae, Solanaceae, or Brassicaceae. In gel diffusion tests with symptomatic leaves from tobacco, this virus reacted with antiserum to tobacco streak virus (TSV) HR strain, but did not react with antisera to alfalfa mosaic or with antisera to 12 viruses in the NEPO or Sobemovirus groups. Virus in leaves directly from the source shrubs, tested by enzyme-linked immunosorbent assay (ELISA), also reacted with TSV strain HF antiserum. Examination by electron microscopy of leaf dips revealed isometric particles 27 nm in diameter. The now 12-ft tall shrubs were grown from seed imported from China in 1914 (PI 40689). This species is now widely commercially available in the U.S. and grown for its fragrant late winter flowers (2). Viral-infected Lonicera spp. have been reported from Europe, Russia, Japan, and Canada (1). TSV is reported to be seed-borne in several other genera. Among other viruses reported from honeysuckle are Lonicera latent carlavirus, tobacco leaf curl geminivirus, alfalfa mosaic virus, tomato bushy stunt virus, a rhabdovirus, and an aphid transmitted virus.

Impact of flowering on bird community dynamics in some central Victorian eucalypt forests

Many species of Eucalyptus in Australia provide copious amounts of nectar during their reproductive seasons. The nectar is used by many animal species but especially by birds, insects and some bats, which act as pollinators. One of the major features of eucalypt flowering in southern Australia is the patchy, asynchronous flowering of different species, which appears to drive mass nomadism of nectarivorous birds among regions and among habitats. Here we explore whether flowering asynchrony or climate is primarily responsible for the influxes and effluxes of vast numbers of nectarivorous birds in central Victoria, Australia. By using a structured sampling program, we show that winter flowering by red ironbark Eucalyptus tricarpa is the most likely agent controlling avian‐nectarivore dynamics rather than climatic differences among regions. Densities and species richness of nectarivores, and numbers of nectarivory events, are all closely related to measures of flowering intensity. However, non‐ nectarivores, such as insectivores and granivores, show no relationships with either habitat or region. We discuss how dependence on a patchily distributed but highly rewarding resource such as nectar influences population densities and community structure in birds.

The use of the pheno-climatic model for forecasting the pollination of some arboreal taxa

Air temperature is one of the most frequent parameters for the application of pheno-climatic models which can give information for the forecasting of the beginning of pollination of various species. For the present study 12 years of aerobiological monitoring data concerning the pollination of hazel, alder, elm, poplar, and willow have been employed to forecast the beginning of their pollination assuming that the beginning of pollination of one species corresponds to a specific moment of phenological development for another species with later pollination. The difference expressed in days between the pollination of two winter taxa with successive flowering is very variable. If this interval is expressed in terms of heat (summation of mean daily temperature above a certain threshold) the differences are smaller. The delay between the pollination of alder and elm varies between 3 and 21 days depending on the climatic trend, but during this period elm on average accumulates 26 degree-days (base temperature 4°C) with a lesser variability. In this way we can begin to calculate the heat requirement for elm from the beginning of alder flowering. This application can be used for other couples obtaining statistical values which are more significant than those obtained with the phenological model, with the exception of willow. The results indicate that for the majority of the species with winter flowering there is a linear relation between the flowering dates and air temperature.

Floristic and structural habitat preferences of yellow-bellied gliders ( Petaurus australis) and selective logging impacts in southeast Queensland, Australia

The floristic and structural habitat requirements of the yellow-bellied glider ( Petaurus australis) and the influence of selective logging on habitat quality in the Maryborough District of southeast Queensland, Australia were determined. Yellow-bellied gliders showed a definite preference for forest associations which contained gum-barked and winter flowering species. Within these associations, abundance was correlated with microhabitat variables and a structural variable representing forest age and degree of disturbance using a Poisson regression analysis. The significant explanatory variables included the structural variable, site productivity and the number of dead hollow-bearing trees. These variables relate to the foraging and denning requirements of the yellow-bellied glider. Implications for forest management in southeast Queensland include the need to retain both mature gum-barked eucalypt species and live hollow-bearing trees during harvesting operations.

Landscape Dynamics of Bird Communities in Relation to Mass Flowering in Some Eucalypt Forests of Central Victoria, Australia

The large-scale dynamics of bird communities in central Victoria, Australia, were studied in relation to eucalypt flowering by recording community changes throughout the annual cycle in sites north and south of the Great Dividing Range (GDR). Two kinds of forest habitat were considered, one of which flowers profusely in winter ('ironbark') while the other flowers little but over the warmer months ('stringybark'). There were eight sites, two of each habitat in both the northern and southern regions. In the absence of flowering in ironbark sites during summer, the avian communities of both kinds of habitat are virtually the same in each region. However, the sets of communities in each region differ significantly from one another at this time. With the onset of winter flowering, avian community composition in ironbark habitats in each region diverges greatly from the non-flowering ironbark and stringybark communities, but converges back to those communities as flowering declines. Most of these changes are due to the influx of high densities of nectarivores, especially honeyeaters and lorikeets. Such influxes in stringybark habitats did not occur, probably because the flowering intensity was at most an order of magnitude less than that in ironbark sites. The results show the dramatic impact that eucalypt flowering has on avian communities in south-eastern Australia, and the influence of habitat differences. Thus, although nectarivores move into the northern region of the study area to capitalize on winter flowering, they show high habitat specificity and virtually avoid the non-flowering stringybark habitats. The results are discussed in terms of landscape and regional dynamics of birds and the possible interactions among avian sub-communities (the 'nectarivores' and 'non-nectarivores').

Flowering seasonality and flower characteristics ofLoranthus acaciae Zucc. (Loranthaceae): Implications for advertisement and bird-pollination

The flowering biology and pollination ecology ofLoranthus acaciae was studied at Hazeva in the northern Arava Valley in Israel. Flowers at anthesis had red anthers, a red stigma and a green corolla which turned red as a postfloral phenomenon. Their flowering period was approximately 10 months long (from mid-June until mid-April) during which time two main flowering patterns were distinguished. Some plants flowered twice a year, with separate summer and winter flowering periods; other plants flowered continuously, with two peaks, one in the summer and one in the winter. Several significant differences between summer and winter flowering and fruiting were found: (1) the summer flowering period was shorter than that of winter, (2) flowering synchrony between individual plants was lower in summer than in winter, (3) in summer the plants produced a larger proportion of female flowers, whereas in winter most of the plants produced a larger proportion of hermaphrodites, (4) in summer a limited number of plants produced smaller flowers while the majority produced normal-sized flowers, whereas in winter the entire population produced only normal-sized flowers, and (5) fruit set percentage was lower in summer than in winter.L. acaciae was found to be self-compatible, but, since it was not spontaneously self-pollinated, it showed high dependence on pollinator activity. In summer the flowers were visited by a wide spectrum of pollinators, both birds and insects, while in winter flowers were visited almost exclusively by the orange-tufted sunbird (Nectarinia osea osea, Nectariniidae). These seasonal changes in flowering characteristics and pollinator activity could explain why reproductive success is higher in winter than in summer.

トルコギキョウの高温遭遇後の抽だい特性に基づくロゼット性の品種分類

Seedlings of Eustoma grandiflorum (Raf.) Shinn. form rosettes and do not bolt (elongation of internodes) when they are grown at a high temperature. The rosetted plants will bolt after being subjected to a certain period of cool temperature. To explain the rosette characteristics of cultivars, we examined weekly the bolting ratios of every cultivar after high temperature treatments at four experiments, and classified 125 cultivars from the data.When exposed to a cool temperature after a high temperature treatment, the rapidity of bolting was very different among seedlings or cultivars. We considered that the seedlings which bolted early were insensitive to high temperature, conversely, the seedlings bolted late were sensitive and needed longer period of cool temperature for bolting.The species is propagated by seeds and occasionally maintains hybrid vigor by out-breeding. So, individuals in a cultivar are not uniform in their response to a high temperature treatment, and the degree of uniformity differs among cultivars. Therefore, it was necessary to consider not only the rapidity but also the uniformity for classification.Using the data (weekly cumulative bolting ratios), the rapidity and uniformity of bolting were arrived at by ascertaining when the bolting ratio of a cultivar reached 20%, 50%, and 80% (a-value, b-value, and c-value), respectively. The b-value is considered to represent the average rapidity; whereas, the difference between a- and c-value represents the degree of variation within the cultivar. Using this method, the cultivars were classified into grades, A to E based on their b-values, and into categories, 1 to 5 based on theire c- minus a-values. Hence, cultivars classified as being in group A would have seedlings most insensitive to high temperature and which would bolt readily upon exposure to cool temperature; whereas, cultivars in group E would have seedlings most sensitive to high temperature and which tend to remain in the rosette stage for an extended period after being transferred to a cool environment. Cultivars classified as being in category 1 respond uniformly to the temperature treatment, whereas those in category 5 do not. The data obtained in this study with 125 cultivars will be useful for selecting or breeding cultivars which will raise seedling in summer and flower in winter.

In vitro corm production of Gladiolus dalenii and G. tristis

The ability of the summer flowering Gladiolus dalenii Van Geel and the winter flowering G. tristis L. to form corms in vitro was investigated. G. dalenii spontaneously formed corms on a shoot induction medium consisting of the basal medium of Murashige & Skoog (1962) with up to 2.0 mg l-1 benzyladenine (BA), 3% sucrose and solidified with 2 g l-1 Gelrite®. The effect of different BA and sucrose concentrations as well as different temperatures on in vitro corm production of G. tristis was further investigated. The best production of shoots per explant was achieved on a medium containing 0.5 to 1.0 mg l-1 BA, sucrose concentrations of 6 to 9% and cultured at 15°C. The best corm production was achieved at the same temperature and with the same medium with the exception that BA was omitted from the medium. To test the effect of the osmotic potential on the formation of shoots and corms, sucrose was substituted by mannitol at various concentrations. Sucrose proved to be essential for both shoot and corm production and the use of mannitol had no beneficial effect.

Miniature Gladiolus Cultivars Bred for Winter Flowering

Most of the commercial gladioli in the world have been bred to provide cut flowers in the summer. Growing these cultivars in subtropical and Mediterranean climates during the winter months frequently results in low-quality flowers (Halevy, 1985; Magic and Cowperthwaite, 1954; McKay et al., 1981; Shillo and Halevy, 1976a). The failure to grow high-quality gladiolus flowers during the winter months has been attributed to the sensitivity of these summer cultivars to low light intensities (Shillo and Halevy, 1975, 1976b), short photoperiods (Shillo and Halevy, 1976c, 1981), and the combined effect of low irradiance with low night temperatures (Halevy, 1985; Shillo and Halevy, 1963) during flower development. The European restriction on the importation of cut flowers to the winter months generated the need to develop gladiolus cultivars selected to produce high-quality flowers under winter conditions. [In December, the average daylength in Tel-Aviv, Israel, is 10 h and 5 rein, with an average irradiance of 850 to 1000 μmol·s ·2 (400-700 nm).] In addition, the flower industry required a smaller, lightweight flower able to respond favorably to higher density planting, produce higher yields, and reduce shipping costs. In response to the demands of the cut flower industry and the renewed interest in smaller cultivars (Barnard, 1972; Halevy et al., 1984), a new group of miniature gladiolus was developed for the cut flower market. Their main properties are: winter flowering, light weight, and attractive variety of colors. The group was nicknamed ‘Orchidiola’ (orchid glads) by the Israeli flower industry. The name was inspired by the petal shape and the variation

BOOK REVIEWS

Book reviewed in this article:East African Weeds and their Control. G. W. Ivens.The Names of Plants. D. Gledhill. vi + 202 pp.Hardy Orchids. Phillip Cribb and Christopher BailesThe Genus Dionysia. Christopher Grey‐WilsonThe Royal Horticultural Society Gardeners' Encyclopedia of Plants and Flowers. Editor‐in‐chief, Christopher BrickellSarawak. Notes during a residence in that country with H.H. the Rajah Brooke. Hugh Low, with an introduction by R. H. W. ReeceSpring and Winter Flowering Bulbs of the Cape. Barbara Jeppe and Graham DuncanFrench Flower Painters of the 19th Century. Elisabeth Hardouin‐Fugier and Etienne Grafe (ed. by P. Mitchell)The Botanic Garden Wellington, a New Zealand History 1840–1987. Winsome Shepherd and Walter CookFrank Kindon‐Ward. Charles LyteBiddulph Grange, Staffordshire ‐ A Victorian garden rediscovered. Peter HaydenThe Medicinal Plants of Mauritius. Malcy de Chazal.Hellebores. Brian Mathew. 180 pp. including 32 pp. colour plates and photographsModern Miniature Daffodils, Species and Hybrids. James S. WellsThe Green Tapestry. Beth Chatto. 192pp., numerous colour photographs. William CollinsSons &Co. Ltd

Spring and Winter Flowering Bulbs of the Cape.

Spring and Winter Flowering Bulbs of the Cape.

The effects of light spectra fluence, duration and time of application on flowering of Gypsophila

The effectiveness of different lamps and illumination regimes was tested over a wide range of light fluences, thus providing a basis for economic calculations of the optimal illumination regime for winter flowering in Gypsophila. Lamps emitting light in the 550–770-nm range were almost equally suitable. Flowering date was directly related to the logarithm of the total light fluence between 1 and 100 mMol m −2 night −1. The most economical application was to illuminate the plants throughout the night. Cyclic lighting did not provide any saving of energy.

Flowering in a Zostera marina bed off San Juan island (Washington, U.S.A.) during winter

Winter flowering in a shallow bed of Zostera marina L. off San Juan Island (Washington, U.S.A.) is reported. Flowering shoots were scarce (0.8 m −2), grouped in small aggregates of 2–3 shoots, and showed different phases of development. Pollination occurred but no mature fruits or seeds were observed. It is not known whether this out-of-season flowering response was under the influence of environmental factors other than temperature or whether the eelgrass population involved displayed a genotypic variation.

Population Regulation of the Eurasian Pine Adelgid (Homoptera: Adelgidae) in Hawaii

Population dynamics of the Eurasian pine adelgid, Pineus pini (Macquart), and its predator, Leucopis obscura Haliday, were studied over a 2-yr period in Hawaii. Densities of both species tended to be lowest during the summer dry season and highest at times of increased rainfall and tree flowering in winter. Correlation analysis of predator and adelgid densities indicated that the P. pini population was regulated by L. obscura at its higher densities, below economically significant levels.

Forecasting of banana harvest (‘Williams’) in the subtropics using seasonal variations in bunch development rate and bunch mass

Forecasting banana supplies is an important priority both for growers and for the local marketing organisation. Achieving this requirement is complicated by the floral ontogeny of banana which induces flowering and fruit production throughout the year. At the two experimental localities Burgershall and Levubu, in the Eastern Transvaal, totals of 2571 and 2057 ratoon ‘Williams’ banana bunches, respectively, from uniform plantations, were analysed over a 3-year period. Mean flower emergence to harvest interval and mean bunch mass were calculated for 24 flowering periods of 15 days each. Seasonal variations at both localities were substantial and were related to temperatures prevailing at flower initiation and during fruit development. At Burgershall, the shortest flowering to harvest interval was 110 days (early summer flowering) and the longest 204 days (autumn flowering). Bunch mass varied from 57.8 kg (July flowering) to 37.2 kg (October flowering), the latter bunches resulting from winter flower initiation. Levubu data differed substantially from Burgershall, although the seasonal trends were similar. A practical crop forecasting model is proposed which is based on new flower counts every 15 days, and the overall box/bunch potential of the grower. Using the experimental data base, the total boxes are forecast from seasonal yield adjustment factors, and harvest spread is forecast from the harvest distribution of experimental bunches for each flowering period. Each cultivar-locality combination must be forecast separately, and the model assumes year-to-year uniformity, farm-to-farm uniformity, optimum management, and an absence of major damage due to wind, hail or frost.