Morphology of Anemone sylvestris L. flower (Ranunculaceae)

During the monitoring of populations of Anemone sylvestris L. (Ranunculaceae), a protected species in Poland, we found that the seed set is impaired. The flower is considered an adaptation that has coevolved to achieve effective pollination and successful fertilization. Therefore we have focused on the morphological and anatomical characteristics of the flowers of A. sylvestris L. as a prelude to the study of the species’ pollination biology and plant breeding system. The large size of the flower (50.6 ± 16.4 mm in dimensions) and its bowl shape fulfil both the biotic pollination syndrome and the aerodynamic requirements for pollen dispersal and capture. The opening and closing of the perianth provide a shelter for beetles. The odourless perianth, absence of nectar, scarcity of pollen (approximately 200 000 pollen grains per flower) and its traits – small size (axis P = 18.52 ± 1.0 μm; E = 16.59 ± 0.9 μm), lack of balsam on the exine surface, starch accumulation in more than 95% of pollen grains correspond to the specialization in anemophily. The stigma is papillous, the dense hairs are situated between single carpels indicating adaptation to capturing dry pollen and specialization in the wind pollination syndrome. The flower of A. sylvestris is an example for an intermediate form between entomophily and anemophily, i.e. a secondary and more advanced feature among Ranunculaceae

Floral nectar production and carbohydrate composition and the structure of receptacular nectaries in the invasive plant Bunias orientalis L. (Brassicaceae)

The data relating to the nectaries and nectar secretion in invasive Brassicacean taxa are scarce. In the present paper, the nectar production and nectar carbohydrate composition as well as the morphology, anatomy and ultrastructure of the floral nectaries in Bunias orientalis were investigated. Nectary glands were examined using light, fluorescence, scanning electron and transmission electron microscopy. The quantities of nectar produced by flowers and total sugar mass in nectar were relatively low. Total nectar carbohydrate production per 10 flowers averaged 0.3 mg. Nectar contained exclusively glucose (G) and fructose (F) with overall G/F ratio greater than 1. The flowers of B. orientalis have four nectaries placed at the base of the ovary. The nectarium is intermediate between two nectary types: the lateral and median nectary type (lateral and median glands stay separated) and the annular nectary type (both nectaries are united into one). Both pairs of glands represent photosynthetic type and consist of epidermis and glandular tissue. However, they differ in their shape, size, secretory activity, dimensions of epidermal and parenchyma cells, thickness of secretory parenchyma, phloem supply, presence of modified stomata and cuticle ornamentation. The cells of nectaries contain dense cytoplasm, plastids with starch grains and numerous mitochondria. Companion cells of phloem lack cell wall ingrowths. The ultrastructure of secretory cells indicates an eccrine mechanism of secretion. Nectar is exuded throughout modified stomata

Aspekty kwitnienia, pylenia i oblotu przez owady kilku gatunków z rodzaju Hydrangea L.

In the years 2001-2004 the observations of blooming and the abundance of pollen flow delivered by Hydrangea shrubs were made. Hydrangea heteromalla D. Don, H. arborescens L., H. arborescens ssp. discolor (Raf.) McClintock, H. paniculata 'Grandiflora' grown in the Botanical Garden in Lublin were studied. The investigated species form inflorescences consisting of two types of flowers. Fertile flowers deliver pollen flow and sterile flowers attract pollinators optically. The following pollen efficiency values were measured: 0.6 g (H. paniculata 'Grandiflora'), 7-11 g (H. arborescens, H. arborescens ssp. discolor), 19.7 g (H. heteromalla) per one shrub, on average. The main pollinators were Apis mellifera, Bombus sp., Andrena, while H. paniculata attracted mainly Diptera.W latach 2001-2004 prowadzono obserwacje kwitnienia i oblotu przez owady oraz badano obfitość pylenia 4 gatunków hortensji: Hydrangea heteromall D. Don, H. arborescens L., H. arborescens ssp. discolor (Raf.) McClintock, H. paniculata 'Grandiflora'. Krzewy rosły w kolekcji Ogrodu Botanicznego UMCS w Lublinie. W kwiatostanach występowały dwa rodzaje kwiatów: płodne dostarczające pyłku i płone stanowiące powabnię optyczną dla owadów. Jeden krzew dostarczał przeciętnie 0,6 g pyłku (H. paniculata 'Grandiflora'), 7-11 g (H. arborescens, H. arborescens ssp. discolor), 19,7 g (H. heteromalla). Owadami odwiedzającymi kwiaty hortensji były przede wszystkim pszczołowate, głównie pszczoła miodna oraz trzmiele i pszczoły samotnice, tylko w przypadku H. paniculata dominowały muchówki

Distribution and abundance of bee forage flora across an agricultural landscape – railway embankments vs. road verges

In this study, we evaluated if railway embankments and road verges create refuge habitats for bee flora across agricultural landscape. The survey was conducted in 2009–2012, in the Lublin Province, SE Poland. Data on the bee forage flora were obtained while making floristic charts along 60 transect plots × 300 m, with a total length of 18 000 m, for each type of linear structure. Forage bee flora was compared with respect to species richness, diversity, and evenness indices. The canonical correspondence analysis (CCA) was used to characterize relationship between species composition and environmental variables. The bee forage species richness and abundance were significantly greater on railway embankments than on road verges. The composition of species varied considerably; the number of bee forage species common to both habitats was only approximately 38% in entire data set. Most good-value bee forage species were recorded along the embankments of railways with an intermediate traffic volume. Bee forage species diversity benefits from the location of habitat elements (forests or meadows), primarily if the distance is <50 m. The lack of dense patches of valuable bee forage species in the road verges was related to the high density of non-nectariferous graminoids. Our results demonstrate how the value of man-made areas in an agricultural ecosystem can vary with respect to floral resources across the landscape, suggesting that it is inappropriate to generalize about agricultural systems as a whole without first addressing differences among habitats

Floral biology of Senecio macrophyllus M. BIEB. (Asteraceae), a rare Central European steppe plant

Knowledge of the flowering phase and plant pollination ecology is very important for understanding the life history of long-lived perennials. In the case of rare species, the information may have implications for conservation practices. Our studies on flower morphology and blooming biology of the vulnerable plant Senecio macrophyllus M. BIEB. were conducted in situ (flowering, activity of insect visitors) in the largest population in SE Poland and in laboratory (light and scanning electron microscopy). The disc florets open diurnally with most intensive anthesis in the early afternoon and attract insect visitors with nectar and pollen. In highly protandrous disc florets, pollen viability decreases in time, whereas stigma receptivity increases. The upper part of the pistil forms a brush-like pollen presenter, covered with unicellular trichomes with chromoplasts. Pollen presentation lasts 4–11 hours per floret, and 8 days in a single head, the main function of which is to extend the availability of male gamets for reproduction. The number of florets per head, the head size, and the number of pollen grains produced per anther, and the pollen grain viability differed significantly between microsites. The finding indicates that, apart from the biotic factors, abiotic conditions may considerably influence generative reproduction of the species. In the study area, the principal visitors of S. macrophyllus flowers were Hymenoptera, with predominance of Apis mellifera (53.4% of visits). The remarkable share of butterflies (13.9%) recognized as the long-distance moving insects may improve the genetic variability of individuals within a fragmented population. A more detailed study is necessary to explain the role of insect visitors in effective pollination and in gene transfer between patches. The assessment of optimal conditions for the generative reproduction is fundamental for the in situ conservation of this rare species

Pollination and floral biology of Adonis vernalis L. (Ranunculaceae) – a case study of threatened species

Although the knowledge of pollination systems of rare and threatened species is one of the principles for development of optimal conservation and management strategies, the data about their pollination requirements are scarce or incomplete. Different problems are listed (xerothermic habitat disappearance, overgrowing of patches, plant biology i.e., slow plant growth, problems with seed germination) among the possible causes of Adonis vernalis being threatened, but until now no consideration was given to the flowering biology and pollination. The observations of flowering biology of A. vernalis (Ranunculaceae), a clonal species, were conducted in an out-of-compact-range population, in the Lublin Upland, Poland (51°18'55" N, 22°38'21" E), in 2011–2013. The reproductive potential of A. vernalis is related to the population age structure, pollination syndrome, and breeding system. The flowers exhibit incomplete protogyny. The dichogamy function is supported by different (biological, morphological) mechanisms. Stigma receptivity occurred about one day before anthers started shedding self-pollen, and pollen viability was increasing gradually during the flower life-span (66.3% in distal anthers vs. 77.3% in proximal). The decrease in pollen production and in pollen viability coincided with the lowest degree of seed set, irrespective of the pollination treatment. Pollen vectors are necessary for efficient pollination, as the proportion of pistils setting fruits after open pollination (41–82.1%) was significantly higher compared to spontaneous self-pollination (only 5.5–12.3%). The pollination requirements together with pollen/ovule ratio (P/O = 501) indicate a facultative xenogamous breeding system in A. vernalis. Therefore, in the conditions of the global lack of pollinators, improper pollination may weaken the population by leading to a decrease in the proportion of recombinants, and in addition to other factors, may accelerate extinction of small A. vernalis populations

Nectar and pollen production of Helianthus tuberosus L. – an exotic plant with invasiveness potential

In Central Europe, Helianthus tuberosus L. is a late summer/autumn bloomer (August/November). The disc florets produce both nectar and pollen. Floral reward is available in male-phase flowers (pollen and nectar) and in female-phase flowers (nectar). The floral reward is attractive to a variety of insect visitors (honey bees, wasps, flies and butterflies). The season of blooming as well as the total sugar yield (25.4 – 47.4 kg ha–1) and pollen yield (57.8 – 212.7 kg ha–1) indicate that H. tuberosus is important in the enhancement of food resources for pollinators. The generative reproduction in H. tuberosus is impaired (the species does not set seeds/fruits). However, due to its attractiveness for a variety of pollinators in both rural and urban areas, the spread of H. tuberosus should be monitored. Moreover, its propagation needs to be attended with restrictions

The influence of artificial wind blow on the pollination and fructification of blackcurrant (Ribes nigrum L.) cultivars

The experiment of the additional blow of bushes of 8 cultivars of blackcurrant (Ribes nigrum L.) was conducted in 1995–1997 in Pulawy, Poland. The artificial wind blow generated by the vacuum cleaner fan was used. The additional blow of freepollinated and isolated bushes did not caused better pollination of flowers and did not have any positive effect on the weight of 100 fruits, the yield structure or the number of seeds per fruit.Badania dodatkowego owiewania krzewów 8 odmian porzeczki czarnej prowadzono w latach 1995–1997 na terenie RZD w Puławach. Wykorzystano ruch powietrza pochodzący od wentylatora odkurzacza. Dodatkowe owiewanie krzewów zarówno swobodnie dostępnych dla owadów, jak i całkowicie izolowanych nie wpłynęło na lepsze zapylenie kwiatów, nie powodował również zmian w strukturze plonu, masie owoców oraz liczbie zawartych w nich nasion

The need for weeds : man-made, non-cropped habitats complement crops and natural habitats in providing honey bees and bumble bees with pollen resources

In Europe, honey bees and bumble bees are among the most important pollinators, and there is a growing interest in understanding the effects of floral resource availability on their survival. Yet, to date, data on nectar and pollen supplies available to bees in agricultural landscapes are still scarce. In this paper, we quantify species-, habitat- and landscape-scale pollen production in the Lublin Upland, SE Poland. The production per unit area was highest (mean = 2.2–2.6 g/m$^{2}$) in non-forest woody vegetation, field margins and fallows, whilst significantly lower pollen amounts were shown to be available in road verges and railway embankments (mean = 1.3–1.6 g/m$^{2}$). At landscape scale, natural and semi-natural areas (forests and meadows/pastures) offered ca. 44% of the total pollen resources during the year. Relatively high amounts of pollen (ca. 35% of the year-round total pollen resources) were from winter rape, but this resource was short-term. Man-made, non-cropped habitats added only ca. 18% of the total pollen mass offered for pollinators during flowering season. However, they provided 66–99% of pollen resources available from July to October. There exists an imbalance in the availability of pollen resources throughout the year. Hence, a diversity of natural, semi-natural and man-made, non-cropped areas is required to support the seasonal continuity of pollen resources for pollinators in an agricultural landscape. Efforts should be made to secure habitat heterogeneity to enhance the flower diversity and continual pollen availability for pollinators

Invasive flora within urban railway areas: a case study from Lublin (Poland) and Lviv (Ukraine)

Heterogeneous and disturbed habitats within railway areas create an ideal environment for establishment of invasive plant species. In this study, we compared the invasive species composition and abundance within railway areas of two cities, Lublin, SE Poland and Lviv, W Ukraine. In total, 70 invasive species were recorded. The invasive species list was similar for the two cities, with the most invasive species occurring at both (81.4%), 8.5% occurring only in Lublin and 10% only in Lviv. The proportion of invasive species in the total flora was almost 1.5-fold higher at Lviv compared to Lublin. Invasive species have originated mainly from continental America (45.7%), followed by Asia and Eurasia. The participation of invasive plants derived from Asia and Eurasia at Lviv is higher than at Lublin. The invasive flora includes a wide range of taxonomic groups, with a predominance of Asteraceae and Poaceae. The ecological attributes of invasive species on railway areas are: mainly annual therophytes, mostly wind- and insect pollination modes, a predominance of generative reproduction, anthropochorous and anemochorous dispersal and short-term persistent, long-term persistent or transient seed banks