scholarly journals Sensitivity of commercial pumpkin yield to potential decline among different groups of pollinating bees

2017 ◽  
Vol 4 (5) ◽  
pp. 170102 ◽  
Author(s):  
Sonja C. Pfister ◽  
Philipp W. Eckerter ◽  
Jens Schirmel ◽  
James E. Cresswell ◽  
Martin H. Entling
Keyword(s):  
Crop Yield ◽  
Fruit Set ◽  
Pollen Grains ◽  
Pollen Deposition ◽  
Insect Pollination ◽  
Study Region ◽  
Flower Visitation ◽  
Pollen Receipt ◽  
The Relationship ◽  
Pollinator Fauna

The yield of animal-pollinated crops is threatened by bee declines, but its precise sensitivity is poorly known. We therefore determined the yield dependence of Hokkaido pumpkin in Germany on insect pollination by quantifying: (i) the relationship between pollen receipt and fruit set and (ii) the cumulative pollen deposition of each pollinator group. We found that approximately 2500 pollen grains per flower were needed to maximize fruit set. At the measured rates of flower visitation, we estimated that bumblebees (21 visits/flower lifetime, 864 grains/visit) or honeybees (123 visits, 260 grains) could individually achieve maximum crop yield, whereas halictid bees are ineffective (11 visits, 16 grains). The pollinator fauna was capable of delivering 20 times the necessary amount of pollen. We therefore estimate that pumpkin yield was not pollination-limited in our study region and that it is currently fairly resilient to single declines of honeybees or wild bumblebees.

Staminodes influence pollen removal and deposition rates in nectar-rewarding self-incompatible Phanera yunnanensis (Caesalpinioideae)

2019 ◽  
Vol 35 (1) ◽  
pp. 34-42
Author(s):  
Menglin Wang ◽  
Shuyin Huang ◽  
Manru Li ◽  
Doyle McKey ◽  
Ling Zhang
Keyword(s):  
Fruit Set ◽  
Removal Rate ◽  
Apis Cerana ◽  
Pollen Dispersal ◽  
Adaptive Significance ◽  
Western China ◽  
Pollen Deposition ◽  
Deposition Rates ◽  
Flower Visitation ◽  
Pollen Removal

AbstractStaminodes are sterile stamens that produce no pollen, exhibit diverse structures and perform various functions. Flowers of Phanera yunnanensis possess three fertile stamens with large anthers and long filaments, and seven staminodes with tiny anthers and short filaments. To investigate the adaptive significance of staminodes in this species, we studied effects of staminode removal on pollen removal and deposition, flower visitation rate and fruit set in Xishuangbanna, south-western China. Four species of nectar-foraging pollinators visited flowers, mostly Amegilla zonata and Apis cerana (2.80 ± 0.15 and 1.76 ± 0.41 visits h−1 per flower, respectively). Staminode removal did not affect fruit set, but increased visitation by A. cerana by 2.6-fold, reduced visitation by A. zonata by 68% and increased the pollen removal rate for both pollinators (all effects were significant). Staminode removal significantly reduced pollen deposition rate for A. zonata, but not for A. cerana. These results suggest that the staminodes of P. yunnanensis filter which insects act as pollinators and affect pollen removal and deposition rates. By reducing pollen removal rates, staminodes may implement a pollen-dispensing schedule that spreads pollen dispersal from individual flowers over multiple pollinators. By altering pollen deposition rates, staminodes may influence reproductive fitness in other ways.

scholarly journals Floral herbivory does not reduce pollination-mediated fitness in shelter rewarding Royal Irises

2017 ◽  
Author(s):  
Mahua Ghara ◽  
Christina Ewerhardy ◽  
Gil Yardeni ◽  
Mor Matzliach ◽  
Yuval Sapir
Keyword(s):  
Fruit Set ◽  
Seed Set ◽  
Pollen Grains ◽  
Reproductive Organs ◽  
Pollen Grain ◽  
Lower Number ◽  
Pollen Deposition ◽  
Pollination Services ◽  
Pollinator Visitation ◽  
Direct Damage

ABSTRACTFlorivory, the damage to flowers by herbivores can affect fitness both directly and indirectly. Flowers consumed by florivores may fail to produce fruit or produce lower seed set because of direct damage to reproductive organs. In addition, eaten flowers are less attractive to pollinators because of reduced or modified advertisement, which reduces pollination services. While observational data are abundant, experimental evidence is scarce and results are contrasting. We tested experimentally the effect of florivory on both pollinator visitation and reproductive success in three species of the Royal Irises, which have large flowers that are attractive to pollinators, and potentially also for florivores. We hypothesized that florivory will reduce pollen deposition due to reduced attractiveness to pollinators, while fruit set and seed set will depend on the extent of florivory. We performed artificial florivory in two experiments over two years. In the first experiment, each of the three floral units of a single Iris flower was subject to either low or high artificial florivory, or left un-touched as control. We counted the number of pollen grains deposited on each of the three stigmas as a measure of pollinator visitation. In the second experiment, three flowers of the same plant received low, high, or no artificial florivory and were further recorded for fruit and seed production. In 2016, high artificial florivory revealed lower number of pollen grains on stigmas of Iris atropurpurea, but in 2017 there was no difference. Similarly, number of pollen grains in high artificial was lower than low florivory in 2017 in I. petrana. No significant effect of florivory was found on pollen grain deposition, fruit set or seed set. The results remained consistent across species and across years. The results undermine the assumption that flower herbivory is necessarily antagonistic interaction and suggests that florivores may not be strong selection agents on floral reproductive biology in the Oncocyclus irises.

scholarly journals Fruit Set in Avocado: Pollen Limitation, Pollen Load Size, and Selective Fruit Abortion

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1603
Author(s):  
María L. Alcaraz ◽  
José I. Hormaza
Keyword(s):  
Fruit Set ◽  
Pollen Limitation ◽  
Pollen Grains ◽  
Endosperm Development ◽  
Pollen Deposition ◽  
Woody Perennial ◽  
Flowering Season ◽  
Fruit Abortion ◽  
Load Size ◽  
Competition For Resources

Avocado is a woody perennial fruit crop originating in Central America and Mexico domesticated and cultivated in the Americas since pre-Columbian times, currently cultivated in subtropical, tropical, and Mediterranean climates worldwide, with increasing importance in international trade. Avocado shows an exuberant flower production that, however, results in a very low fruit set reflected in a massive abscission of flowers and fruitlets. Several factors are involved in this behavior, and, in this work, we have focused on pollination limitation. The results obtained show that pollen deposition takes place at the female and male stages during the avocado flowering season and that the percentage of flowers with pollen on the stigma varies along the flowering season, probably due to changes in temperature that affect not only the floral behavior but also pollinator activity. However, no embryo or endosperm development took place when pollination occurred during the male flowering phase. Thus, the low number of pollen grains landing on the stigmas of female stage flowers observed under natural pollination conditions might not be enough to ensure a good yield. The production of an excess of flowers and subsequent flower drop of most of the flowers provides the opportunity of a selective fruitlet drop depending on the genotype of the embryo since fruits derived from outcrossing showed higher chances of reaching maturity. Moreover, an important competition for resources occurs among developing fruits and new vegetative growth, conferring importance to the time of flower fertilization for effective fruit set.

The effects of nectar level and flower development on pollen carry-over in inflorescences of fireweed (Epilobium angustifolium) (Onagraceae)

1985 ◽  
Vol 63 (3) ◽  
pp. 488-491 ◽  
Author(s):  
C. Galen ◽  
R. C. Plowright
Keyword(s):  
Plant Species ◽  
Flower Development ◽  
Nearest Neighbor ◽  
Pollen Grains ◽  
Pollen Deposition ◽  
Nectar Production ◽  
Epilobium Angustifolium ◽  
Carry Over ◽  
Pollen Receipt ◽  
Female Flowers

Nectar in flowers of Epilobium angustifolium was manipulated experimentally to provide enriched versus depleted reward levels to bumblebee pollinators. Bumblebees visited significantly more flowers on inflorescences with high rewards than low ones and stayed longer on individual flowers with high rewards. The greatest pollen deposition occurred in older female flowers having enriched nectar levels. In older female flowers the stigma lobes coil backward, reducing the distance between their receptive surfaces and the nectary site. Younger female flowers, regardless of reward level, only occasionally received more than a few pollen grains per bee visit. Although higher nectar levels are likely to promote pollen receipt over the course of a flower's lifetime, because of changes in stigma configuration with flower development, the number of pollen grains transferred to the stigma at any given time depends on the flower's age as well as its reward status. In this self-compatible plant species, most of the increase in pollen receipt resulting from high nectar production is likely to lead to self-matings since (i) plants are clonal and bees usually fly to nearest neighbor ramets after rewarding visits, (ii) bees visit more flowers on enriched inflorescences than on depleted ones, and (iii) pollen carry-over declines exponentially over the course of an inflorescence visit.

Triploidy causes sexual infertility in Cyrtanthus breviflorus (Amaryllidaceae)

2011 ◽  
Vol 59 (3) ◽  
pp. 238 ◽  
Author(s):  
Mike Ramsey ◽  
Glenda Vaughton ◽  
Glendon D. Ascough ◽  
Steven D. Johnson
Keyword(s):  
Flow Cytometry ◽  
Genetic Factors ◽  
Fruit Set ◽  
Pollen Viability ◽  
Pollen Grains ◽  
Clonal Plants ◽  
Pollen Deposition ◽  
Sexual And Asexual Reproduction ◽  
Challenging Question

The balance between sexual and asexual reproduction can vary markedly in clonal plants. At one extreme, plants are sexually infertile and reproduction is solely clonal. Infertility can be caused by environmental and/or genetic factors, but the role of each is often unknown. Here we determine variation in sexual reproduction and explore the underlying factors causing sexual infertility in Cyrtanthus breviflorus Harv. We examined open- and cross-pollinated fruit set, ploidy using flow cytometry, pollen viability, pollinator visits to flowers and pollen deposition onto stigmas. One population was sexually infertile; no plants produced fruit. Three populations were sexually fertile; >98% of plants produced fruit. Percent pollen viability differed between infertile (18%) and fertile (97%) populations. The most likely cause of infertility was unequal ploidy. Plants in the infertile population were triploid, whereas those in fertile populations were diploid. Pollination factors were not related to infertility. In infertile and fertile populations, pollen-collecting insects visited flowers frequently, depositing 4-fold more pollen grains onto stigmas than the number of ovules per flower. Our study is the first to demonstrate infertility and triploidy in C. breviflorus. How triploidy became established despite high levels of pollinator activity remains a challenging question.

scholarly journals Herkogamy but not reciprocity is a better predictor of legitimate pollen transfer and fruit set in Jasminum malabaricum, a self-compatible species with stigma-height dimorphism

2020 ◽  
Author(s):  
Shatarupa Ganguly ◽  
Deepak Barua
Keyword(s):  
Reproductive Success ◽  
Fruit Set ◽  
Natural Populations ◽  
Negative Relationship ◽  
Pollen Deposition ◽  
Pollen Transfer ◽  
Style Length ◽  
Individual Level ◽  
Reciprocal Arrangement ◽  
The Relationship

AbstractPremiseReciprocity and herkogamy, morphological traits that define style length polymorphisms, are thought to be critical in determining legitimate inter-morph pollen transfer in plants with style length polymorphism. However, the consequences of individual-level variation in these traits for pollen transfer and reproductive success have rarely been examined, and the relationship between these two fundamental traits remains unexplored.MethodsWe quantified individual-level estimates of herkogamy and reciprocity and tested the assumption that higher herkogamy and reciprocity result in higher legitimate pollen transfer and reproductive success in natural populations of Jasminum malabaricum, a species that exhibits stigma-height dimorphism. Additionally, we examined the relationship between herkogamy and reciprocity to understand potential consequences for avoiding self-pollination and encouraging legitimate pollen deposition.ResultsSurprisingly, reciprocity was not related to pollen load, legitimate pollen fraction or reproductive success. In contrast, herkogamy was positively associated with legitimate pollen fraction and fruit set in the long-styled morph. Interestingly, we observed a negative relationship between herkogamy and reciprocity in the long-styled morph.ConclusionsHerkogamy was more important than reciprocity in increasing legitimate pollen transfer and reproductive success in J. malabaricum. Herkogamy might be particularly important in stabilising species with stigma-height dimorphism and other such polymorphic intermediates with low reciprocity, and this may allow the evolution of reciprocal arrangement of sex organs at a later stage in the pathway towards distyly. The negative relationship between herkogamy and reciprocity suggests a trade-off between avoidance of self-pollen deposition and promotion of legitimate pollen deposition.

K-MEANS CLUSTERING ALGORITHM BASED CLASSIFICATION OF SOIL FERTILITY IN NORTH WEST NIGERIA

2020 ◽  
Vol 4 (2) ◽  
pp. 780-787
Author(s):  
Ibrahim Hassan Hayatu ◽  
Abdullahi Mohammed ◽  
Barroon Ahmad Isma’eel ◽  
Sahabi Yusuf Ali
Keyword(s):  
Soil Fertility ◽  
Crop Yield ◽  
Clustering Algorithm ◽  
Soil Samples ◽  
North West ◽  
R Programming ◽  
Available Information ◽  
Northwest Region ◽  
The Relationship

Soil fertility determines a plant's development process that guarantees food sufficiency and the security of lives and properties through bumper harvests. The fertility of soil varies according to regions, thereby determining the type of crops to be planted. However, there is no repository or any source of information about the fertility of the soil in any region in Nigeria especially the Northwest of the country. The only available information is soil samples with their attributes which gives little or no information to the average farmer. This has affected crop yield in all the regions, more particularly the Northwest region, thus resulting in lower food production.  Therefore, this study is aimed at classifying soil data based on their fertility in the Northwest region of Nigeria using R programming. Data were obtained from the department of soil science from Ahmadu Bello University, Zaria. The data contain 400 soil samples containing 13 attributes. The relationship between soil attributes was observed based on the data. K-means clustering algorithm was employed in analyzing soil fertility clusters. Four clusters were identified with cluster 1 having the highest fertility, followed by 2 and the fertility decreases with an increasing number of clusters. The identification of the most fertile clusters will guide farmers on where best to concentrate on when planting their crops in order to improve productivity and crop yield.

scholarly journals Spatial–Temporal Impacts of Urban Sprawl on Ecosystem Services: Implications for Urban Planning in The Process of Rapid Urbanization

Land ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1210
Author(s):  
Xiaoyan Li ◽  
Gulinaer Suoerdahan ◽  
Zhenyu Shi ◽  
Zihan Xing ◽  
Yongxing Ren ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
Urban Planning ◽  
Carbon Storage ◽  
Crop Yield ◽  
Urban Sprawl ◽  
Habitat Suitability ◽  
Urban Areas ◽  
Water Retention ◽  
Rapid Urbanization ◽  
Study Region

Rapid urbanization drives land cover change, affecting urban ecosystems and inducing serious environmental issues. The study region of Changchun, China was divided into three urbanization categories according to different urbanization levels and the characteristics of urban sprawl and changes and relationships between typical ecosystem services (ESs) under rapid urbanization were analysed. The results showed that Changchun has undergone considerable urban expansion since 2000, which has significantly impacted all ESs in terms of spatial and temporal heterogeneity. Habitat suitability and crop yield have relatively stronger service capacity in the study area. Since the expansion of large-scale infrastructures, the mean ES values of developed urban areas are the lowest among the three zones, except for water retention and sandstorm prevention in 2015, when the balance between all services decreased. Over the past 16 years, habitat suitability in developing urban areas has decreased to a large extent due to urban sprawl. Because of the improvement in agricultural science and technology, crop yield in three regions increased, while the area of cropland reduced from 1720 km2 to 1560 km2 (9.3%). Synergies between habitat suitability and carbon storage and habitat suitability and soil retention were detected in three areas. A trade-off between habitat suitability and water retention was detected in three areas. The interactions between crop yield and carbon storage, habitat suitability, and soil retention were more complex in this study region. In addition to water retention, urbanization index has a negative correlation with ESs. According to the results, some suggestions to alleviate ES loss during the process of rapid urbanization were proposed, which may guide scientific urban planning for sustainable urban development.

scholarly journals The Relationship of Crop Yield and Weather

Nature ◽  
1928 ◽  
Vol 122 (3068) ◽  
pp. 258-258
Author(s):  
E. V. N.
Keyword(s):  
Crop Yield ◽  
Relationship Of ◽  
The Relationship
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