Mg Of Pollen Research Articles

<i>Prunus spinosa</i> L. pollen - quantity and nutritional quality

Pollen production and pollen quality in <i>Prunus spinosa</i> L. (Rosaceae), a common early-spring flowering plant from the temperate zone was evaluated. The species is an efficient pollen producer, as it can produce 0.23 mg of pollen per flower and 1.99 g of pollen per 1 m<sup>2</sup> of shrub surface, however, the values may differ considerably between seasons. Its pollen contains a high amount of proteins (22.1–34.2%). The total lipid content in the pollen ranged between 2.7 and 3.6%. The presence of omega-3, omega-6, and omega-9 fatty acids was found. Among omega-3 fatty acids, inflammation inhibitors, i.e., α-linolenic acid and arachidonic acid, were detected. The predominant mineral was potassium, followed by calcium and magnesium. <i>P. spinosa</i> pollen is an important ingredient of bee pollen loads containing 89.1–98.2% of <i>Prunus pollen</i>. <i>P. spinosa</i> should be recommended for planting in the agricultural landscape in order to support the early spring diet for pollinators.

Nectar secretion and pollen production in Hyacinthus orientalis ‘Sky Jacket’ (Asparagaceae)

Flowering, nectar secretion, and pollen production in <em>Hyacinthus orientalis</em> ‘Sky Jacket’ (Asparagaceae) were studied between 2013 and 2015 in Lublin, SE Poland (51°16' N, 22°30' E). The flowering was weather-dependent. It started at the beginning of April or at the end of the month and lasted 14–24 days. The mass of nectar, sugar concentration in the nectar, nectar sugar mass, anther size, and pollen mass in flowers all depended on the flower position in the inflorescence and differed significantly between the years of study. The greatest mass of sugars and pollen was recorded in low-positioned flowers. On average, <em>H. orientalis</em> ‘Sky Jacket’ produced 1.63 mg of sugars and 3.51 mg of pollen per flower. The floral reward was attractive for <em>Apis mellifera</em> and <em>Bombus</em> spp., which indicate that the species should be propagated not only for its decorative value but also for supporting pollinators in early spring.

Nectar and pollen production in ornamental cultivars of Prunus serrulata (Rosaceae)

Abstract Planting ornamental species can help to create pollinator-friendly habitats. In the present study the flowering phenology and floral reward (nectar and pollen) in two cultivars of Prunus serrulata (‘Kanzan’ and ‘Amanogawa’) were evaluated in 2014-2015 in the city of Lublin (south-east Poland). On average, the onset of flowering of P. serrulata occurred in the first ten days of April (‘Kanzan’) or at the end of April (‘Amanogawa’), and lasted 8-17 days. In each year of the study, P. serrulata ‘Kanzan’ started flowering 11-18 days earlier than P. serrulata ‘Amanogawa’. The double flowers of P. serrulata ‘Kanzan’ offered only tiny amounts of nectar and pollen. The total mass of sugars was 0.59 mg per flower and that of pollen 0.08 mg per flower. The semi-double flowers of P. serrulata ‘Amanogawa’ produced 4.5 mg of sugars per flower and 0.17 mg of pollen per flower. The frequency of pollinator visits to flowers was low in P. serrulata ‘Amanogawa’ and very low in P. serrulata ‘Kanzan’. Therefore, if pollinator-friendly arrangements are made in urban areas, these cultivars should not be planted.

Micromorphological and histochemical attributes of flowers and floral reward in Linaria vulgaris (Plantaginaceae)

The self-incompatible flowers of Linaria vulgaris have developed a range of mechanisms for attraction of insect visitors/pollinators and deterrence of ineffective pollinators and herbivores. These adaptive traits include the flower size and symmetry, the presence of a spur as a “secondary nectar presenter,” olfactory (secondary metabolites) and sensual (scent, flower color, nectar guide—contrasting palate) signals, and floral rewards, i.e. pollen and nectar. Histochemical tests revealed that the floral glandular trichomes produced essential oils and flavonoids, and pollen grains contained flavonoids, terpenoids, and steroids, which play a role of olfactory attractants/repellents. The nectary gland is disc-shaped and located at the base of the ovary. Nectar is secreted through numerous modified stomata. Nectar secretion began in the bud stage and lasted to the end of anthesis. The amount of produced nectar depended on the flower age and ranged from 0.21 to 3.95 mg/flower (mean = 1.51 mg). The concentration of sugars in the nectar reached up to 57.0%. Both the nectar amount and sugar concentration demonstrated a significant year and population effect. Pollen production was variable between the years of the study. On average, a single flower of L. vulgaris produced 0.31 mg of pollen. The spectrum of insect visitors in the flowers of L. vulgaris differed significantly between populations. In the urban site, Bombus terrestris and Apis mellifera were the most common visitors, while a considerable number of visits of wasps and syrphid flies were noted in the rural site.

Effect of sodium chloride, PGDO and Arabic gum in pollen liquid diluent on suspensibility of kiwi pollen

This study was conducted to develop the pollen liquid diluent suitable for the artificial pollination of kiwi. The pollen of ‘Matua’ kiwi was collected at 1 day before flowering. Five concentrations of sodium chloride (0, 50, 150, 250, and 350 mg․L -1 ), four concentrations of poly (glycolide-co-p-dioxanone) (0, 7, 14, and 21 mg․L -1 ), and four concentrations of arabic gum (0, 150, 350, and 550 mg․L -1 ) were tested on an absent condition of each component in the pollen liquid diluent. Twenty mg of pollen was distributed in beakers containing 10 mL of the pollen liquid diluent. Suspensibility of the pollen liquid diluent was measured by the sensory evaluation and particle size analyzer. The addition of sodium chloride in pollen liquid diluent was effectible for the suspensibility improvement and the promotion of pollen growth in kiwi pollen. The kiwi pollen in pollen liquid diluent could be suspended without damage in pollen germination at low concentration of poly (glycolide-co-p-dioxanone) (PGDO), which has been known as a safe surfactant. The addition of Arabic gum would be highly advantageous to the stabilization of the pollen liquid diluent without any contamination for pollen growth. Kiwi fruits were set and grown well by the artificial pollination using the pollen liquid diluent. Therefore, the use of the pollen liquid diluent in the artificial pollination of kiwi fruit should be an effective practice.

Pollen productivity and morphology of pollen grains in two cultivars of honeyberry (Lonicera kamtschatica (Sevast.) Pojark.)

In the years 2004-2006, investigations on the abundance of pollen production in two cultivars of <i>Lonicera kamtschatica</i> (Sevast.) Pojark. - Atut and Duet, were conducted at the Felin Experimental Farm of the Agricultural University in Lublin. Moreover, the viability of pollen grains was estimated and measurements of their size were taken. Ten flowers of both studied cultivars supplied 11.42 mg of pollen and the average pollen productivity per 1 ha of a several-years-old plantation was 30.04 kg. The pollen of the observed plants was eagerly collected by honey bees. Pollen grains of both cultivars are suboblate. Considering their size, they can be described as large ones (P=47.55 µm, E=60.37 µm). Pollen viability for both cultivars is high, about 95%.

Pollen production and characteristics of pollen grains in two species of Camassia Lindl. (Hyacinthaceae)

In the years 1999-2001 the study was carried out in the area of UMCS Botanical Garden in Lublin. Plants of <i>Camassia cusickii</i> S.Wats. and <i>Camassia leichtlinii</i> (Bak.) S.Wats. bloomed in May. During a day peak, of flowering occurred at 17.00 h. All anthers shed pollen simultaneously, just after tepals were expanded. Ten flowers produce 10.6-12.8 mg of pollen. The pollen viability ranged from 58 to 92%. The length of longitudinal equatorial axis (E) in <i>Camassia</i> Lindl. pollen grains reached 57,7 µm.

Flowering of two Arctium L. species and their significance as a source of pollen for visiting insects

SummaryThis study conducted in the years 2004–6 concerned the biology and abundance of flowering as well as pollen productivity of Arctium lappa L. (great burdock) and Arctium tomentosum Mill. (woolly burdock) (Asteraceae), growing in natural habitats in the area of Lublin, Poland (51° 14' N and 22° 34' E). Arctium tomentosum started to bloom in late June or early July, with A. lappa two to three weeks later. The flowering of these plants lasted for 6 to 9 weeks, depending on the species and weather conditions. During the growing season, one plant developed 10–15 lateral branches, comprising 320–471 flower heads which produced bisexual tubular florets. The mean number of flowers in the A. lappa inflorescence reached 79.5; in A. tomentosum 45.9. A single plant of A. lappa produced 29.8 thousand florets; A. tomentosum 13.2 thousand. The mean pollen mass produced by 10 florets was very similar for both species, reaching 2.91 mg and 2.99 mg, respectively. One flower head of A. lappa may provide 22.55 mg of pollen, compared to 13.72 mg of A. tomentosum. Pollen yield from one plant averaged 8.45 g and 3.94 g, respectively, corresponding to 23.6 g and 15.4 g per 1 m2.

Pollen production, flowering and insect visits on Euphorbia cyparissias L. and Euphorbia virgultosa Klok

SummaryThis study investigated the morphological features, flower biology, pollen output and insects which foraged on Euphorbia cyparissias L. and Euphorbia virgultosa Klok. The observations were made between 2002 and 2006 on ruderal plots in Lublin, south eastern Poland. Both species formed inflorescences of the pseudantium type, known as cyathia. The number of inflorescences was 117.06 per shoot for E. cyparissias and 84.72 for E. virgultosa. The opening of spathe in the successive cyathia occurred almost simultaneously in both species, as early as at 6.00 h with the peak between 7.00 and 8.00 h. All cyathia of E. cyparissias are hermaphroditic. In the case of E. virgultosa, the bisexual cyathia on the shoots accounted for 58.3%. Hermaphroditic cyathia are protogynous. Dichogamy in Euphorbia virgultosa is strengthened through the occurrence of exclusively male flowers in part of the cyathia. The mean number of anthers per cyathium in E cyparissias and E. virgultosa, was 17.22 and 14.22, respectively. The small stamens of E. cyparissias yielded a mean of 0.38 mg of pollen per 100 anthers while the larger stamens of E. virgultosa yielded 0.51mg per 100 anthers. The weight of pollen per plant averaged 2.64 mg in E. virgultosa and 3.68 mg in E. cyparissias. Several hymenopteran species (Apis mellifera L. and solitary bees) visit E. cyparissias flowers. Additionally, Bombus spp. forages on E. virgultosa. Among the pollinators of both plants taxa, Diptera were present. Over the five-year period of observation, the density of species studied per square unit varied, but the plants renew each year. The associations with E. cyparissiasand E. virgultosa are not subjected to rapid succession. Hence, the studied species should be considered as an important component of the food chain for Apoidea and Diptera.

An Isorhamnetin Rhamnoglycoside Serves as a Costimulant for Sugars and Amino Acids in Feeding Responses of Adult Western Corn Rootworms (Diabrotica virgifera virgifera) to Corn (Zea mays) Pollen

Adult beetles of Diabrotica virgifera virgifera LeConte (western corn rootworm) feed on pollen of Zea mays L. (corn) and other plant species. To identify D. virgifera feeding stimulants, beetle responses to mixtures of known and novel phagostimulants, presented at their naturally occurring concentrations in maize pollen, were compared to individual component responses applying the amount occurring in 0.2 mg of pollen per cellulose feeding disk. On a molar basis, three major sugars (fructose, glucose, and sucrose) were more prevalent in corn pollen buffer extract (CPE) than free amino acids. Western corn rootworm feeding was stimulated by the three sugars (28% disk consumption) and, to an even greater extent, by a mixture of 21 free amino acids (41% disk consumption). However, the combination of three sugars and 21 amino acids elicited a level of D. virgifera feeding (41% disk consumption) similar to that of the 21 amino acids alone. A novel maize pollen phagostimulant was purified from CPE by using solid-phase extraction followed by RP-HPLC. Based on its mass fragment pattern, two UV maxima (254 and 359 nm), and previous isolation from maize pollen, this phagostimulant is tentatively identified as isorhamnetin 3-O-neohesperidoside. This compound interacted additively with the mixture of three sugars and 21 amino acids, to produce 77% of the phagostimulation level of CPE. Therefore, a possible stimulatory mechanism for D. virgifera feeding on corn pollen has been elucidated.

Maize Pollen Coat Xylanase Facilitates Pollen Tube Penetration into Silk during Sexual Reproduction

Cell wall hydrolases are well documented to be present on pollen, but their roles on the stigma during sexual reproduction have not been previously demonstrated. We explored the function of the tapetum-synthesized xylanase, ZmXYN1, on maize (Zea mays L.) pollen. Transgenic lines (xyl-less) containing little or no xylanase in the pollen coat were generated with use of an antisense construct of the xylanase gene-coding region driven by the XYN1 gene promoter. Xyl-less and wild-type plants had similar vegetative growth. Electron microscopy revealed no appreciable morphological difference in anther cells and pollen between xyl-less lines and the wild type, whereas immunofluorescence microscopy and biochemical analyses indicated an absence of xylanase on xyl-less pollen. Xyl-less pollen germinated as efficiently as wild-type pollen in vitro in a liquid medium but less so on gel media of increasing solidity or on silk, which is indicative of partial impaired water uptake. Once germinated in vitro or on silk, the xyl-less and wild-type pollen tubes elongated at comparable rates. Tubes of germinated xyl-less pollen on silk did not penetrate into the silk as efficiently as tubes of wild-type pollen, and this lower efficiency could be overcome by the addition of xylanase to the silk. For wild-type pollen, coat xylanase activity on oat spelled xylan in vitro and tube penetration into silk were inhibited by xylose but not glucose. The overall findings indicate that maize pollen coat xylanase facilitates pollen tube penetration into silk via enzymatic xylan hydrolysis.

Quantification of consumption of corn pollen by the predator Coleomegilla maculata (Coleoptera: Coccinellidae) during anthesis in an Illinois cornfield

Abstract 1 Coleomegilla maculata DeGeer feeds on corn pollen in the field, but the degree to which this predator relies on corn pollen as part of its diet is not well understood. We quantified the amount of pollen consumed by C. maculata second, third and fourth instars and adults in the field.2 Laboratory experiments were conducted to determine the digestion rate and duration of different stadia or stages using temperature regimens that reflected field conditions during anthesis. Coleomegilla maculata larvae and adults were collected from the field and the amount of pollen in their digestive tracts was determined gravimetrically. The rate of digestion, duration of each life stage and the field observations were used to estimate the amount of pollen consumed by second, third and fourth instars and adults.3 Our models estimate that larvae consume 0.66, 1.67 and 3.30 mg of pollen during the second, third and fourth stadia, respectively. Adults consumed an estimated 13.15 mg during anthesis.4 The relevance of our results to ecological risk assessment of transgenic insecticidal corn and predator life history strategies is discussed. The results presented here are a first attempt to quantify pollen consumption by a predator, and future areas of research are suggested.

Pollen consumption in honey bee larvae: a step forward in the risk assessment of transgenic plants

In order to assess the potential impacts of transgenic plants on larvae of the honey bee, Apis mellifera, information on pollen consumption is needed. We here report on experiments that were conducted with small bee colonies kept in field cages (8 × 14 m) containing only flowering maize plants as protein source. Fully grown worker bee larvae were found to contain between 1720 and 2310 maize pollen grains in their gut before defecation, corresponding to 1.52-2.04 mg of pollen consumed per larva. On average, 74.5% of pollen grains were completely digested while 23.3% were partially digested and 2.2% remained undigested. Our data indicate that the contribution of the protein by directly feeding larvae with pollen is less than 5% in relation to the total amount of protein necessary for complete larval development. We suggest that our measurement for pollen consumption should be taken into account when establishing dose regimes to assess the risk that transgenic plants pose for honey bee larvae. Apis mellifera / pollen consumption / transgenic plant / agrochemical / maize / risk assessment

Uridine Diphosphate Glucose Metabolism and Callose Synthesis in Cultured Pollen Tubes of Nicotiana alata Link et Otto.

Membrane preparations from cultured pollen tubes of Nicotiana alata Link et Otto contain a Ca2+ -independent (1-3)-[beta]-D-glucan (callose) synthase activity that has a low affinity for UDP-glucose, even when activated by treatment with trypsin (H. Schlupmann, A. Basic, S.M. Read [1993] Planta 191: 470-481). Therefore, we investigated whether UDP-glucose was a likely substrate for callose synthesis in actively growing pollen tubes. Deposition of (1-3)-[beta]-glucan occurred at a constant rate, 1.4 to 1.7 nmol glucose min-1, in tubes from 1 mg of pollen from 3 h after germination; however, the rate of incorporation of radioactivity from exogenous [14C]-sucrose into wall polymers was not constant, but increased until at least 8 h after germination, probably due to decreasing use of internal reserves. UDP-glucose was a prominent ultraviolet-absorbing metabolite in pollen-tube extracts, with 1.6 nmol present in tubes from 1 mg of pollen, giving a calculated cytoplasmic concentration of approximately 3.5 mM. Radioactivity from [14C]-sucrose was rapidly incorporated into sugar monophosphates and UDP-glucose by the growing tubes, consistent with a turnover time for UDP-glucose of less than 1 min; the specific radioactivity of extracted UDP-[14C]glucose was equal to that calculated from the rate of incorporation of [14C]sucrose into wall glucans. Large amounts of less metabolically active neutral sugars were also present. The rate of synthesis of (1-3)-[beta]-glucan by nontrypsin-treated pollen-tube membrane preparations incubated with 3.5 mM UDP-glucose and a [beta]-glucoside activator was slightly greater than the rate of deposition of (1-3)-[beta]-glucan by intact pollen tubes. These data are used to assess the physiological significance of proteolytic activation of pollen-tube callose synthase.

Pollination of radish byApis cerana

SUMMARYIn the Kathmandu valley of Nepal radish (Raphanus sativus) plants had an average often branches, each with 155.2 ± 18.3 flowers, 14.1 ± 1.3 mm in diameter. Flowers opened in the morning and remained open for two to three days. Flowering began in the first week of March and lasted for one month. Apis cerana workers foraged on radish plants for 11.5 hours each day, from 06.40 h (26 min after sunrise) to 18.30 h (18 min after sunset) with peak foraging between 11.00 h and 14.00 h. At 09.00, 12.00 and 15.00 h respectively, workers averaged 4.3, 5.3 and 12.8 s per flower, visited 8.0, 9.0 and 5.0 flowers per minute and collected 11, 10 and 7 mg of pollen. Most workers collected either pollen or nectar, but 4–7% collected both nectar and pollen during the same foraging trip. Pod set, number of seeds per pod, seed weight and germination for radish plants caged with an A. cerana colony were 45%, 42%, 45% and 73% greater, respectively, than for open-pollinated plants. Plants with insect visitors excluded had no pod set.

Antigen-induced eustachian tube obstruction: An intranasal provocative challenge test

ETO and symptoms of AR have been demonstrated to develop after an intranasal provocative antigen-challenge test. To determine the antigen dose required to produce ETO, intranasal insufflations of increasing amounts of pollen (ragweed or timothy) from 0.1 to 100 mg were delivered to 29 patients, ages 20 to 31 yr with AR who were skin test positive or had elevated serum-IgE antibodies to ragweed or timothy but not pine pollen. Our results demonstrated ETO developed in four ears at 0.05 mg of pollen, in one at 0.5 mg, in four at 1 mg, in 28 at 10 mg, in 15 at 50 mg, and in two at 100 mg of pollen. ETO persisted from 2 to 120 hr. Dose responses and duration of ETO were compared to patients' serum-IgE antibodies that ranged from 3% to 36% B T (median 26.4%). The patients with the highest serum-IgE antibody values (≥26.4%) required lower antigen-dose challenges (≤10 mg) to develop ETO ( p ≤ 0.01) that also persisted longer (≤48 hr) p ≤ 0.05. Symptoms of AR developed with an antigen dose that was less than the antigen dose that resulted in the development of ETO in 22 patients and at the same antigen dose in the other seven subjects. At a later date, these same subjects were also challenged intranasally with 50 mg of pine pollen after which no symptoms of AR or development of ETO were noted. In summary, the expression of ETO after provocative intranasal pollen challenge in AR patients is an immune-mediated reaction that is antigen-dose dependent and related to serum-IgE antibody titer.

The Significance of Pollen in the Diet of the New Holland Honeyeater, Phylidonyris Novaehollandiae (Aves : Meliphagidae).

New Holland honeyeaters obtain negligible nutriment from pollen. Three lines of evidence show that the contents of pollen grains are not extracted during passage through the birds. Firstly, the proportion of empty pollen grains in faecal samples did not differ from that in samples of pollen dusted off the facial feathers of wild birds. Secondly, the proportion of empty pollen grains in samples taken at successive points along the alimentary canal from oesophagus to cloaca did not change in the 10 birds examined. Finally the condition of pollen fed to caged birds did not change with passage through the birds. Quantities of pollen ingested by honeyeaters are small, around 300,000 pollen grains or 15 mg of pollen per day. Even if fully digested this uould provide only a small proportion of the birds' protein requirements and a negligible amount of energy. Pollen is probably collected accidentally while the birds collect nectar from flowers.

Foraging behavior of honeybees on white clover

Measurements of several aspects of foraging behavior of honeybees on white clover and of factors that might influence it were made at one-to-two-week intervals during the season. Other measurements were made on intervening days. Individual blossoms yielded a mean of from 0.02 to 0.08 μl of nectar containing 42 to 65% sugar during the season. On one day when the nectar averaged 65% sugar, bees with pollen on their corbiculae carried a mean of 5.2 mg of pollen and 37.3 mg of nectar; bees without pollen carried a mean of 37.9 mg of nectar. On 10 occasions each of 50 bees were timed while foraging a single blossom; the mean foraging speed differed significantly on the 10 occasions, and varied from 1.5 to 3.0 seconds per blossom. Each of 18 bees was timed during visits to 25 blossoms, and the total time required for the same bees to forage from the blossoms on 25 racemes was also measured. The mean foraging speed of these bees varied from 1.1 to 4.5 seconds per blossom; the differences were highly significant. These bees foraged 7.0 to 26.0 blossoms per minute, and there was a strong negative correlation between the mean seconds required for bees to forage blossoms and the mean number of blossoms foraged per minute. Fifty one bees observed for a total of 314.5 minutes foraged an average of 18.4 blossoms per minute and 3.4 blossoms per inflorescence. Sixty one per cent of the flights of foraging bees were made to inflorescences estimated to be less than 5 inches from the starting point.