ARTICLE | doi:10.20944/preprints202012.0449.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: climate change; crop pollination; functional traits; global warming; pollination; seed production; self-incompatibility; Sinapis alba
Online: 18 December 2020 (08:55:25 CET)
Climate change is likely to have a complex effect on the growth of plants, their phenology, plant-pollinator interactions, and reproductive success. Therefore, we tested the impact of three key factors (temperature, water, and nitrogen supply) on traits, pollination, and seed production in Sinapis alba (Brassicaceae). We grew the plants in different combinations of temperature, water, and nitrogen supplementation, measured multiple vegetative and floral traits, and assessed the response of pollinators in the field. We also evaluated the effect of growing conditions on seed set in plants exposed to pollinators and hand-pollinated plants. Our results show that water stress impaired vegetative growth, decreased flower production, reduced visitation by pollinators and seed set, while nitrogen availability played an important role in nectar production. Temperature modulated the effect of water and nitrogen availability on vegetative and floral traits and strongly affected flowering phenology and flower production. We demonstrated that changes in temperature, water, and nitrogen availability induce changes in plant vegetative and floral traits which impact flower visitation and consequently plant reproduction. Climate change, particularly increasing temperature combined with reduced precipitation, thus may impact plant-pollinator interactions with negative consequences for the reproduction of wild plants and insect-pollinated crops.
COMMUNICATION | doi:10.20944/preprints202212.0429.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: onion; PCR inhibition; pollenkitt; wetted pollen; pollination
Online: 22 December 2022 (12:58:49 CET)
There is little information on the use of pollen in molecular research, despite the increased interest to genome editing by pollen mediated transformation. PCR is useful tool as an express-method to evaluate editing results before pollination. A direct PCR protocol for pollen suspension has been adapted without the need for DNA pre-extraction. We showed that pollenkitt is a limiting factor for successful PCR on pollen. A simple pre-washing step of pollen suspension was able to eliminate the pollenkitt and enormously affect the PCR results. All currently existing methods of delivery of the editing system to pollen are carried out in a wet medium. Our pollenkitt study helped us develop a simple and effective pollination method using wetted onion pollen grains.
ARTICLE | doi:10.20944/preprints202012.0826.v2
Subject: Biology And Life Sciences, Insect Science Keywords: Amegilla; Gossypium barbadens; Meskine; pollination efficiency; yields
Online: 27 August 2021 (14:08:15 CEST)
This study was carried out to evaluate the impact of Amegilla calens bee on fruit and seed yields of G. hirsutum in an experimental field, in September 2018 and 2019. The experiments were carried out on 540 flowers divided in four treatments: 120 flowers accessible to all visitors; 120 flowers bagged to avoid all visits; 200 flowers protected and uncovered when they were opened, to allow A. calens visits; 100 flowers bagged then uncovered and rebagged without the visit of insects or any other organism. Bees daily rhythm of activity, its foraging behaviour on flowers, its pollination efficiency, the fruiting rate, the number of seeds per fruit and the percentage of normal seeds were evaluated. Results indicate that among 11 insect species recorded on flowers, X. olivacea ranked second and harvested nectar. Throughout the pollination efficiency of a single flower visit, X. olivacea provoked a significant increase of the podding rate, the mean number of seeds per pod, the percentage of normal seeds and the mean weight of a seed by 39.48 %, 18.19 %, 49.62 % and 31.53 % respectively. The conservation and installation of X. olivacea nests close to P. vulgaris fields is recommended to improve its pod production and seed quality.
ARTICLE | doi:10.20944/preprints202306.0391.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: Outcrossing; isolation distance; varietal purity; pollen movement; faba bean pollination
Online: 6 June 2023 (07:04:58 CEST)
Faba bean (Vicia faba L.) is a partially outcrossing species requiring an isolation distance to maintain genetic purity when more than one variety is grown in field conditions. This information is crucial for seed growers and faba bean breeders. A study was conducted at the University of Sydney’s Plant Breeding Institute, Narrabri over two years to examine the extent of natural outcrossing using a creamy white flower characteristic as a morphological marker, which is controlled by a single recessive gene. The white flowered genotype (IX225c) was grown in paired rows of 150 m length in four directions from a central 480 m2 plot of the normal flowered genotype PBA Warda. A beehive was placed in the central plot at flowering time and natural pollination was allowed. At maturity, seed samples were taken from the white flowered genotype at designated intervals along each axis and 100 seeds from each sample were grown in the glasshouse/birdcage to the 4-5 leaf stage and the proportion of plants displaying stipule spot pigmentation (normal flower colour and spotted stipule are linked) was used to determine the percentage of outcrossing. Maximum outcrossing of 2.28% occurred where both genotypes were grown side by side (0 m) and the degree of outcrossing decreased as the distance along each axis from the central plot increased. At 6 m distance the outcrossing was less than 1%, however on occasion it increased to 1% beyond a distance of 100 m, indicating the volatile and unpredictable nature of bee flights. Distance had the major effect on outcrossing, but direction and its interaction had no effect. The results suggest that to limit outcrossing to below 0.5%, a distance of more than 150 m between plots of different faba beans cultivars would be required. It also indicated that Australian faba bean genotypes are mostly self-fertile and a relatively narrow isolation distance will ensure self-fertilization in seed production and breeding programs.
REVIEW | doi:10.20944/preprints202004.0465.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: terrestrial orchids; threatened; species; conservation; propagation; translocation; pollination; adaptive management
Online: 26 April 2020 (02:17:01 CEST)
This paper presents a comprehensive and adaptive framework for orchid conservation programs illustrated with data from published and unpublished case studies. There is a specific focus on West Australian terrestrial orchids, but many of the approaches have universal relevance. Aspects of the framework include (1) setting appropriate objectives, (2) establishing effective collaborations between scientists, volunteers and regulators to fill knowledge and funding gaps, (3) use of survey and demographics data to determine extinction risks and management requirements for species, (4) effective habitat management to overcome threats such as grazing, (5) finding potential new habitats by modelling climate and site data, (6) investigating the effectiveness of pollinators and (7) using seed baiting to detect mycorrhizal fungi. The relative cost and effectiveness of different methods used to propagate orchids for translocation are compared. Methods known to be successful, in order of complexity, include placement of seed in situ, vegetative propagation, symbiotic germination in non-sterile organic matter, symbiotic germination in sterile culture, asymbiotic sterile germination and clonal division in tissue culture. These form a continuum of complexity, cost, time required, faculties needed, as well as the capacity to maintain genetic diversity and produce seedlings preadapted to survive in situ. They all start with seed collection and lead to seed storage, living collections used as tuber banks and seed orchards, as well as translocation for conservation. They could also lead to commercial availability and sustainable ecotourism, both of which are needed to reduce pressure on wild plants. Overall, there has been a strong preference to use relatively complex, expensive and time-consuming methods for orchid conservation, despite evidence that simpler approaches have also been successful. These simpler methods, which include in situ seed placement and non-sterile germination on inorganic substrates, should be trialled in combination with more complex orchid propagation methods as part of an adaptive management framework. It is essential that orchid conservation projects harness the unique biological features of orchids, such as abundant seed production and mycorrhizal fungi which are far more widespread than their hosts. This is necessary to increase the efficiency and coverage of recovery actions for the largest and most threatened plant family.
ARTICLE | doi:10.20944/preprints202207.0143.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: pollination; pollen adhesion; pollenkitt; atomic force microscopy; cryogenic scanning electron microscopy; centrifugation
Online: 10 July 2022 (05:57:28 CEST)
Although pollination is one of the most crucial biological processes that ensures plant reproduction, its mechanisms are poorly understood. Especially in insect-mediated pollination, a pollen undergoes several attachment and detachment cycles when being transfered from anther to insect and from insect to stigma. The influence of the surface properties of pollen, insect and floral surfaces on the adhesion forces that mediate pollen transfer are poorly studied. Here, we investigate the adhesive properties of Hypochaeris radicata pollen and their dependence on pollen ageing by quantifying the pull-off forces from glass slides using centrifugation and atomic force microscopy. We found that the properties of the pollenkitt – the viscous, lipid liquid on the surface of most pollen grains – influences the forces necessary to detach a pollen from hydrophilic surfaces. Our results show that aged H. radicata pollen form weaker adhesions to hydrophilic glass than fresh ones. On the other hand, when a pollen grain ages in contact with glass, the adhesion between the two surfaces increases over time. This study shows for the first time the pollen ageing effect on the pollination mechanism.
ARTICLE | doi:10.20944/preprints202101.0164.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Arbutus unedo L. Artificial Pollination, Breeding, Drought stress, Microscopy, Pollen, Physiological performance
Online: 8 January 2021 (14:08:49 CET)
Arbutus unedo L. is a small Ericaceae tree with a circum-Mediterranean distribution. It has a huge ecological impact on southern Europe forests and a great economic importance, as a source of phytochemicals with bioactive properties and for fruit production. On the foreseen climate change context, breeding towards drought tolerance is necessary in order to ameliorate plant performance. The aim of this work was therefore to study the reproduction mechanisms of strawberry tree, obtain new genetic combinations by hybridization and select genotypes more tolerant to drought stress. A morphological analysis of flowers and pollen was carried out, and controlled pollinations performed both in vitro and ex vitro. The very first approach on strawberry tree breeding by means of hybridization is also presented. Several physiological parameters were evaluated on 26 genotypes submitted to a water deficit regime. Plant behavior under drought greatly varied among genotypes, which showed a high phenotype plasticity. Three genotypes that were able to cope with water restriction without compromising net CO2 assimilation were identified as highly tolerant to drought stress. The results obtained elucidate the reproduction mechanisms of strawberry tree and open the way for a long-term breeding program based on the selection of drought tolerant plants.
ARTICLE | doi:10.20944/preprints202002.0321.v1
Subject: Biology And Life Sciences, Virology Keywords: honey bee; deformed wing virus; RNA virus vector; invertebrate virus; virus evolution; pollination; food security
Online: 23 February 2020 (12:15:14 CET)
We developed a honey bee RNA-virus vector based on the genome of a picorna-like Deformed wing virus (DWV), the main viral pathogen of the honey bee (Apis mellifera). To test the potential of DWV to be utilized as a vector, the 717 nt sequence coding for the enhanced green fluorescent protein (eGFP), flanked by the peptides targeted by viral protease, was inserted into an infectious cDNA clone of DWV in-frame between the leader protein and the virus structural protein VP2 genes. The in vitro RNA transcripts from egfp-tagged DWV cDNA clones were infectious when injected into honey bee pupae. Stable DWV particles containing genomic RNA of the recovered DWV with egfp inserts were produced, as evidenced by cesium chloride density gradient centrifugation. These particles were infectious to honey bee pupae when injected intra-abdominally. Fluorescent microscopy showed GFP expression in the infected cells and Western blot analysis demonstrated accumulation of free eGFP rather than its fusions with DWV LP and/or VP2 proteins. Analysis of the progeny egfp-tagged DWV showed gradual accumulation of genome deletions for egfp, providing estimates for the rate of loss of a non-essential gene an insect RNA virus genome during natural infection.
ARTICLE | doi:10.20944/preprints202001.0309.v1
Subject: Computer Science And Mathematics, Computer Science Keywords: feature selection; hybrid optimization; Whale Optimization Algorithm; Flower Pollination Algorithm; classification; Opposition Based Learning; Email Spam Detection
Online: 26 January 2020 (07:07:23 CET)
Feature Selection (FS) in data mining is one of the most challenging and most important activities in pattern recognition. The problem of choosing a feature is to find the most important subset of the main attributes in a specific domain, and its main purpose is removing additional or unrelated features, and ultimately improving the accuracy of the classification algorithms. As a result, the problem of FS can be considered as an optimization problem, and use metaheuristic algorithms to solve it. In this paper, a new hybrid model combining whale optimization algorithm (WOA) and flower pollination algorithm (FPA) is presented for the problem of FS based on the concept of Opposition based Learning (OBL) which name is HWOAFPA. In our proposed method, using natural processes of WOA and FPA, we tried to solve the problem of optimization of FS; and on the other hand, we used an OBL method to ensure the convergence rate and accuracy of the proposed algorithm. In fact, in the proposed method, WOA create solutions in their search space using the prey siege and encircling process, bubble invasion and search for prey methods, and try to improve the solutions for the FS problem; along with this algorithm, FPA improves the solution of the FS problem with two global and local search processes in an opposite space with the solutions of the WOA. In fact, we used all of the possible solutions to the FS problem from both the solution search space and the opposite of solution search space. To evaluate the performance of the proposed algorithm, experiments were carried out in two steps. In the first stage, the experiments were performed on 10 FS datasets from the UCI data repository. In the second step, we tried to test the performance of the proposed algorithm in terms of spam e-mails detection. The results obtained from the first step showed that the proposed algorithm, performed on 10 UCI datasets, was more successful in terms of the average size of selection and classification accuracy than other basic metaheuristic algorithms. Also, the results from the second step showed that the proposed algorithm which was run on the spam e-mail dataset, performed much more accurately than other similar algorithms in terms of accuracy of detecting spam e-mails.
ARTICLE | doi:10.20944/preprints201807.0027.v1
Subject: Business, Economics And Management, Economics Keywords: pollination value; native bees; economics; production function; willingness to pay; contingent valuation; stated preference; wild blueberry; cranberry; survey
Online: 3 July 2018 (06:33:59 CEST)
Recent pollinator declines have focused efforts on their conservation which require clear estimates of pollination value to agriculture. Our socio-economic producer surveys and agronomic field research data were used to present a new way of estimating ecosystem service value of native pollinators. Using two regionally important U.S.A. crops, Maine wild blueberry and Massachusetts cranberry as models, we present perceived values of native bee pollinators from both consumer and producers. Wild blueberry’s Replacement Cost (RC) was greater than Attributable Net Income (ANI), since greater rented honey bee stocking densities are required. Attributable Net Income for native bees were similar for wild blueberry ($613/ha) and cranberry ($689/ha). Marginal Net Farm Income (MNFI) from incrementally adding more hives per ha was greater from stocking a third/fourth hive per ha for cranberry ($6,206) than stocking a ninth/tenth hive per ha for wild blueberry ($556), given greater responsiveness of yield, revenue, and profit to using rented honey bee hives in cranberry compared to wild blueberry. Both crops’ producers were only willing to annually invest $140–188/ha in native pollination enhancements on their farms, justifying government support. Consumers are willing to pay ~6.7 times more to support native bees than producers, supporting market-based support for invertebrate conservation.
REVIEW | doi:10.20944/preprints201910.0204.v1
Subject: Biology And Life Sciences, Insect Science Keywords: adaptive radiation; sympatric speciation; pollination by sexual swindle; plant insect coevolution; asymmetric coevolution; chemical ecology; Ophrys orchids; unifying species definition; pseudocopulation; key innovation
Online: 17 October 2019 (15:12:38 CEST)
Adaptive radiations occur mostly in response to environmental variation through the evolution of key eco-morphological innovations that allow emerging species to occupy new ecological niches. However, rapid phenotypic evolution and the evolution of key novelties are likely to also occur when a couple or few species are engaged into narrow ecological interactions. To demonstrate coevolution is a difficult task; only elusive evidences confirm that coevolution is a driver of speciation and diversiﬁcation. Here we propose that the adaptive radiation of the Mediterranean orchid genus Ophrys, which gave rise to ca. 350 species since the apparition of the genus is due to the particular co-evolutionary dynamics between these plants and their pollinators. We suggest that the pollination by sexual swindle used by Ophrys orchids is the main driver of this coevolution. Flowers of each Ophrys species mimic sexually receptive females of one particular insect species, mainly bees. Male bees are attracted by pseudo-pheromones emitted by Ophrys flowers that are similar to the sexual pheromones of their females. Males lured by the flower shape, color and hairiness attempt to copulate with the flower, which glues pollen on their bodies. Pollen is eventually transferred to the stigma of another flower of the same Ophrys species during similar copulation attempts. Three observations led us to propose the scenario of an asymmetric co-evolutionary relationship between Ophrys and their pollinators. Firstly, there is a strong intra-specific competition among Ophrys individuals for the attraction of their species-specific pollinators, which is due to the high learning and memorization abilities of bees that record the pheromone signatures of kin or of previously courted partner to avoid (further) copulation attempts. Mnemonic pollinators induce thus a strong selective pressure for variation in the pseudo-pheromones emitted by individual flowers, which will potentially generate shifts in pollinator species, and hence Ophrys speciation. These pollinator shifts are adaptive for new Ophrys species because they may benefit from a competitor-free space. Secondly, such shifts in pollinator species are due to the random crossing of peaks in the olfactory landscape of the pollinator guild that is syntopic to each particular Ophrys population. This selective process on individual, random variation in pseudo-pheromone bouquets is followed by directional selection on flower phenotypes that will reinforce the attraction of the new pollinator. Thirdly, pollinators use the pseudo-pheromones emitted by Ophrys to locate suitable habitats from a distance within complex landscapes. Pollinators stay fixed for a while in these habitats by the local diversity of pseudo-pheromones, which increases their probability of encounter with a receptive female and hence the reproduction probability of both sexes. Conversely, pollinators disperse out of small suitable habitats once they have memorized the local diversity of sexual pseudo-pheromone bouquet or if fecundated Ophrys flowers repel pollinators, which decreases the probability of geitonogamy (plant advantage) but limit pollinator mating with locally emergent insect females, thus limiting inbreeding and favoring gene flow (pollinator advantage). Finally, we propose several research avenues that emerged according to this scenario of adaptive radiation by assymetric coevolution between Ophrys species and their pollinators.