scholarly journals The biology of flowering of winter aconite (Eranthis hyemalis (L.) Salisb.)

2012 ◽  
Vol 64 (2) ◽  
pp. 25-32 ◽  
Author(s):  
Krystyna Rysiak ◽  
Beata Żuraw

<i>Eranthis hyemalis</i> belongs to the Ranunculaceae family whose representatives enrich early spring pollen flow and nectar for pollinating insects. Flowering biology and morphological characteristics flowers of winter aconite were studied. The forage value was estimated as the rate of nectar production. Observations were carried out between 2008 and 2011 in the Botanical Garden of the Maria Curie-Skłodowska University located in the Lublin area. In the conditions of Lublin, flowering of winter aconite plants started at the beginning of February and lasted until the end of March. The seasonal bloom dynamics was strongly affected by maximum temperatures, which intensified flower blooming, and snowfalls which hampered this process. During the day, flowers opened between 8.00 am and 3.00 pm, but the highest intensity was between 10.00 am and 12.00 am. The process of pollen release, with the average number of 29 stamens shedding pollen in the flowers, lasted from 2 to 3 days. During the day the largest number of anthers opened at noon hours, between 11.00 am and 1.00 pm, though a certain rise in this number was also observed in the morning hours between 8.00 and 9.00 am. <i>Eranthis hyemalis</i> flowers develop funnel-shaped nectaries, on average 3-6 per flower. The determined amount of nectar per flower was 1.23 mg, while the concentration of sugars in it averaged 72.11%. The weight of nectar sugar per flower was 0.88 mg.

2007 ◽  
Vol 67 (4) ◽  
pp. 715-719 ◽  
Author(s):  
HF Paulino-Neto

The pollination biology and breeding system of Couepia uiti was studied. In this species, flowers opened at 06:00 AM anthesis, and nectar production began at around 0800 h, reached a maximum volume from 09:30 AM to 10:30 AM, and decreased thereafter. The nectar sugar concentration increased continuously, but showed an abrupt increase from 10:00 AM to 12:00 AM. Pollen release occurred at about 09:30 AM and was quickly collected. The stigmas became receptive at around 12:00 AM. The pollinators of C. uiti included the bees Apis mellifera, Xylocopa sp. and Bombus sp., and three species of wasps. This conclusion was based on the observation that these hymenopterans had C. uiti pollen on their bodies, visited the receptive flowers, and touched the anthers and stigmas, thereby promoting pollination. Of these floral visitors, A. mellifera was considered to be the most efficient pollinator. However, mixed pollination also occurred. The number of C. uiti flowers visited in the morning (n = 52) was three times smaller than in the afternoon (n = 62), and the species richness of floral visitors was also bigger in the afternoon (eight in the afternoon versus five in the morning). This finding indicated that these floral visitors preferred to exploit nectar rather than pollen. Controlled pollination experiments showed that C. uiti was a self-incompatible species that produced fruits only by cross-pollination. Treatments such as agamospermy and spontaneous and self-pollinations did not produce fruits.


2014 ◽  
Vol 67 (3) ◽  
pp. 13-20 ◽  
Author(s):  
Ernest Stawiarz ◽  
Anna Wróblewska

<p class="abstracttekst">Under the conditions of Lublin (central-eastern Poland), observations were conducted on the flowering of <em>Caragana arborescens </em>shrubs for two growth seasons as well as nectar and pollen production by the flowers of this species was investigated.</p><p class="abstracttekst">The flowering period of <em>Caragana arborescens </em>began at the turn of April and May and lasted for 24 days, while for a single flower it was 6.30 ± 0.79 days. The average weight of nectar, sugars and pollen produced by 10 Siberian peashrub flowers was, respectively: 46.70 ± 8.39 mg, 22.79 ± 6.10 mg, and 4.45 ± 0.34 mg. The nectar sugar concentration amounted 49.60 ± 10.08%. Pollen grains reached average dimensions of 21.94 ± 0.76 µm x 21.52 ± 0.71 µm. During a growing season, one <em>Caragana arborescens</em> shrub can provide on average 101.8 g of nectar, 49.7 g of sugars, and 9.7 g of pollen.</p>


1988 ◽  
Vol 78 (4) ◽  
pp. 673-682 ◽  
Author(s):  
Garrick McDonald ◽  
A. Mark Smith

AbstractPopulations of Nysius vinitor Bergroth were studied from 1979 to 1982 in two weed hosts, Arctotheca calendula and Polygonum aviculare, and eight irrigated sunflower crops in a summer cropping area of northern Victoria, Australia. The spring generation began with the adults colonizing flowering A.calendula plants in September and concluded with the rapid development of late stage nymphs and an exodus of adults from these plants from mid-November to December. Gradual invasion of sunflowers occurred mostly in late December and reached a peak at flowering, after which nymphs appeared. P. aviculare attracted adults from February and hosted a number of overlapping generations until winter. The weed sustained diminishing numbers of adults through the winter, except in 1982, when a further generation produced an early spring peak. Immigrant populations were regarded as a common source of adults for initiating the spring and summer generations. The rate of development of N. vinitor in spring was more rapid than that predicted by phenological simulation based on ambient temperatures and laboratory-derived day-degree estimates. This was attributed to increased body temperatures through absorption of solar radiation, and the simulation model was adjusted by increasing daily minimum and maximum temperatures by 1·3 and 5·5°C for young and older instars, respectively. This suggested that older nymphs have lower developmental thresholds or are better able to optimize body temperatures.


2002 ◽  
Vol 80 (11) ◽  
pp. 1203-1208 ◽  
Author(s):  
Lorena Ashworth ◽  
Leonardo Galetto

In dioecious and monoecious plants that depend on animal vectors for reproduction, pollinators have to be attracted to male and female flowers for pollination to be effective. In the monoecious Cucurbita maxima ssp. andreana, male flowers are produced in greater quantity, are spatially more exposed to pollinators and offer pollen in addition to nectar as floral rewards. Nectar traits were compared between male and female flowers to determine any differences in the characteristics of the main reward offered to pollinators. Nectar chemical composition and sugar proportions were similar between flower types. Total nectar sugar production per female flower was threefold higher than per male flower, and nectar removal did not have any effect on total nectar production in both flower morphs. Pollinators reduced nectar standing crops to similar and very scarce amounts in both flower types. Results indicate indirectly that pollinators are consuming more nectar from female flowers, suggesting that the higher nectar production in female flowers may be a reward-based strategy to achieve the high female reproductive output observed in this species.Key words: Cucurbitaceae, Cucurbita maxima ssp. andreana, nectar production, nectar sugar composition, removal effects, standing crop.


2019 ◽  
Vol 14 (3) ◽  
pp. 17-24
Author(s):  
D. M. Anatov ◽  
Z. M. Аsadulaev ◽  
R. M. Osmanov ◽  
K. I. Akhmedova

Aim. The paper presents the results of assessment of the indigenous nature and  degree of similarity of apricot cultivars growing in the collection of the Mountain  Botanical Garden, Gunib, Dagestan, Russia based on a comparative analysis of the  variability of leaf morphological characteristics.   Material and Methods. The material assessed consisted of 33 apricot cultivars of  various ecological and geographical origins aggregated in the following groups: (a)  Dagestan – traditional cultivars; (b) Moscow ‐ selection from the Tsytsin Main Moscow Botanical Garden, Russian Academy of Sciences based on wild forms of Tajikistan and Kyrgyzstan; (c) European and (d) Asian ‐ from Central Asia, Tajikistan, China  and Altai.   Results. The closeness of Dagestan and European varieties in comparison with Asian  and Moscow varieties was shown. Most Dagestan (16 of 19) and European varieties  have round‐shaped leaves (leaf shape index 80‐ 100%), while those from Asia and  the Moscow Botanical Garden have leaves which are elongated elliptical and oval  (60‐80%). Using the method of principal component analysis (PCA), it was established that most cultivars of Dagestan origin have similar leaf shapes and sizes, of  which Tlama kurak (wide‐round), Hekobarsh (elongated) were distinguished by leaf  shape and Esdelik by leaf size.   Conclusion. Based on a discriminant analysis (Squared Mahalanobis Distances), it  was found that the indices of indicators of leaf attributes (width/length of leaf lamina; petiole length/length of lamina; apex angle/corner of leaf base) are more reliable criteria for differentiating apricot varieties into ecological and geographical  groups than their morphological characteristics.  


2021 ◽  
Author(s):  
Ghislain Comlan AKABASSI ◽  
Elie Antoine Padonou ◽  
Achille Ephrem Assogbadjo ◽  
Noël Zirihi Guede

Abstract Picralima nitida is an important African medicinal plant species used in pharmaceutical industries and traditional medicine to treat several diseases. Despite its importance, the species faces conservation problem. This study evaluated the effect of climate and habitat on morphological characteristics and fruit production of P. nitida. A total of 132 fruiting trees was randomly sampled from three habitat types (home gardens, botanical garden and natural forest) and three soils (Nitisols, Arenosols and Acrisols) in Dahomey Gap and Guineo-Congolese zone. A total of 5 morphological traits and fruit production were recorded per tree to describe the relationship between morphological determinism of the species and climate. Pearson correlation was performed to identify the suitable habitat type in each climatic zone. Harmonized World Soil Database was used to determine physicochemical characteristics of the soil types on which the species occurred. Results revealed that the climatic zones (p < 0.001) and habitat types (p < 0.0001) influenced significantly the morphological characteristics and fruit production of P. nitida. High trees with more number of fruits were observed in home gardens on acid soils (Nitisols (pH: 5) and Arenosols (pH: 5.3)) in Dahomey Gap. In Guineo-Congolese zone, the species was more present in natural forest on acid Acrisols (pH: 5).


2000 ◽  
Vol 125 (5) ◽  
pp. 567-575 ◽  
Author(s):  
Cayetana Schluter ◽  
Zamir K. Punja

Morphological characteristics of flowers, duration of flowering, degree of self-pollination, and extent of berry and seed production in North American ginseng (Panax quinquefolius L.) were studied under controlled environmental conditions as well as under field conditions. A comparison was also made between plants of 3 and 4 years of age at two field locations. The duration of flowering was ≈4 weeks and was similar in plants of both age groups grown in the two environments; however, 4-year-old plants produced an average of 40% more flowers (≈100 per plant in total) compared to 3-year-old plants. Flowers were comprised of five greenish-colored petals, five stamens, and an inferior ovary consisting of predominantly two fused carpels and stigmatic lobes. Anthers dehisced in staggered succession within individual flowers, and flowering began with the outermost edge of the umbel and proceeded inwards. At any given time during the 4-week flowering period, ≈10% of the flowers in an umbel had recently opened and were producing pollen. Stigma receptivity was associated with separation of the stigmatic lobes; this occurred at some time after pollen release. Growth of pollen tubes through the style in naturally pollinated flowers was most evident when the stigmatic lobes had separated. The proportion of flowers that developed into mature berries (pollination success rate) was in the range of 41% to 68% for both 3-year-old and 4-year-old plants. However, when the inflorescence was bagged during the flowering period, berry formation was increased by 13% to 21% in 4-year-old plants, depending on location. A majority of the berries (92% to 99%) contained one or two seeds in an almost equal frequency, with the remaining berries containing three seeds. In 4-year-old plants, the frequency of two-seeded berries was increased by ≈13% by bagging the inflorescence. These observations indicate that P. quinquefolius is highly self-fertile and that several physiological and environmental factors can affect seed production.


2019 ◽  
Vol 23 (5-6) ◽  
pp. 803-817 ◽  
Author(s):  
Rosi Rollings ◽  
Dave Goulson

Abstract There is great interest in planting urban areas to benefit pollinating insects, with the potential that urban areas and gardens could act as an extensive network of pollinator-friendly habitats. However, there are a great many different plant cultivars available to the gardener, and a paucity of evidence-based advice as to which plants are truly most attractive to flower-visiting insects. Here, we report insect visitation to metre square plots of 111 different ornamental plant cultivars at a site in central UK. Data were collected over 5 years, and comprise over 9000 insect observations, which were identified to species (for honeybees and bumblebees) or as ‘solitary bees’, Syrphidae, Lepidoptera and ‘others’. Unlike some previous studies, we found no difference in numbers of insects attracted to native or non-native species, or according to whether plants were annuals, biennials or perennials, but we did find that native plants attracted a significantly higher diversity of flower-visiting insects. Overall, the most-visited plants were Calamintha nepeta, Helenium autumnale and Geranium rozanne. However, patterns of visitation were quite different for every insect taxa examined. For example, different species of short-tongued bumblebees showed little overlap in their most-preferred plant cultivars. Interestingly, very similar plant cultivars often attracted different insect communities; for example, 72% of visitors to Aster novi belgii were honeybees or bumblebees, while the related Anthemis tinctoria, which also has daisy-like flowers, did not attract a single honeybee or bumblebee but was popular with solitary bees, hoverflies, and ‘other’ pollinators. Some plant cultivars such as Eryngium planum and Myosotis arvensis were attractive to a broad range of insects, while others attracted only a few species but sometimes in large numbers, such as Veronicastrum virginicum and Helenium autumnale which were both visited predominantly by honey bees. It is clear that we do not yet fully understand what factors drive insect flower preferences. Recommendations are made as to which flower cultivars could be combined to provide forage for a diversity of pollinator groups over the season from early spring to autumn, though it must be born in mind that some plants are likely to perform differently when grown in different environmental conditions.


2019 ◽  
Vol 180 (3) ◽  
pp. 12-18
Author(s):  
K. G. Tkachenko ◽  
G. A. Firsov ◽  
L. F. Yandovka ◽  
A. V. Volchanskaya ◽  
N. E. Staroverov ◽  
...  

Pyrus zangezura Maleev (Rosaceae) is a rare species representing the native vegetation of Armenia (Southern Transcaucasus). It was first described in 1936. P. zangezura has been cultivated at the Peter the Great Botanical Garden of the Komarov Botanical Institute (St. Petersburg, Russia) since 1949, where it has reached the height of 8,0 m. For many years, it was in its vegetative state. The first flowering was observed in 2016 (the plant entered the reproductive state). The first progeny from seed was obtained in April 2019. Fruit size was assessed for P. zangezura plants in the dynamics of their development. The studied plants of P. zangezura in the environments of St. Petersburg have demonstrated a high fruiting potential – on average, 109 flowers per 1 m of a shoot. Observations have shown that not all ovules in the opened flowers of P. zangezura are fertilized and produce fruits and seeds. A significant part of the opened flowers, a few days after the onset of flowering, dry up and fall off. On average, 7 fruits are set on 1 m of the shoot in P. zangezura. The reasons for the low flower setting may be variable: impaired pollination processes and insufficient fertility of pollen, underdevelopment of the flower morphological structures, or lack of pollinating insects due to adverse weather conditions. An X-ray analysis of the seeds from the harvests of 2016, 2017 and 2018 showed that the number of plump and fully developed seeds (grades IV and V) in fruits has been growing year by year. As an ornamental plant, P. zangezura may adorn any botanical garden, but it is also promising for urban landscaping, for example, in St. Petersburg. Even in the vegetative state, its elongated lanceolate glossy leaves make it appreciably different from the common P. communis L., and it is especially ornamental during flowering and fruiting. It is as winter-hardy as the common pear-tree, demonstrates resistance to diseases and pests, and may be of importance for breeding programs aimed at the development of resistant cultivars for the Northwest of Russia.  


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