scholarly journals Corolla Abscission Triggered by Nectar Robbers Positively Affects Reproduction by Enhancing Self-Pollination in Symphytum officinale (Boraginaceae)

Biology ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 903
Author(s):  
Qin-Zheng Hou ◽  
Nurbiye Ehmet ◽  
Da-Wei Chen ◽  
Tai-Hong Wang ◽  
Yi-Fan Xu ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Pollen Viability ◽  
Pollen Grains ◽  
Pollen Deposition ◽  
Nectar Robbing ◽  
Positive Effects ◽  
Symphytum Officinale ◽  
Self Pollination ◽  
Nectar Robbers ◽  
The Impact

Nectar robbers, which affect plant fitness (directly or indirectly) in different degrees and in different ways, potentially constitute a significant part of mutualistic relationships. While the negative effects of nectar robbing on plant reproductive success have been widely reported, the positive effects remain unknown. The target of our study was to evaluate the effects of nectar robbers on the reproductive success of Symphytum officinale (Boraginaceae). We observed the behavior, species and times of visitors in the field, and we assessed the effect of nectar robbers on corolla abscission rate and time. To test the fitness of corolla abscission, we detected the changes in stigma receptivity, pollen viability, pollen amount and appendage opening size along with the time of flower blossom. The flowering dynamics and floral structure were observed to reveal the mechanism of self-pollination. Finally, pollen deposition seed set rate and fruit set rate were determined to estimate the effect of nectar robbers on reproduction success. We observed 14 species of visitors and 2539 visits in 50 h of observation; 91.7% of them were nectar robbers. The pressure and nectar removal of nectar robbers significantly promoted corolla abscission during a period when pollen grains are viable and the stigma is receptive. In addition, corolla abscission significantly increased the pollen deposition and seed setting rate. Our results demonstrate that nectar robbing contributes to enhancing seed production and positively and indirectly impacts the reproductive success of S. officinale. This mechanism involved the movement of anthers and indirect participation by nectar robbers, which was rarely investigated. Considering the multiple consequences of nectar robbing, understanding the impact of nectar robbers on plant reproduction is essential to comprehend the evolutionary importance of relationships between plants and their visitors.

scholarly journals Secondary pollen presentation and foral traits of Heliconia psittacorum

2018 ◽  
Vol 24 (4) ◽  
pp. 451-458
Author(s):  
Talita Oliveira Nascimento ◽  
Patricia Campos Silva ◽  
Vivian Loges ◽  
Sandra Mariotto ◽  
Willian Krause ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Temporal Dynamics ◽  
Pollen Viability ◽  
Pollen Grains ◽  
Pollen Deposition ◽  
Pollen Transfer ◽  
Stigma Receptivity ◽  
Secondary Pollen Presentation ◽  
Self Pollination ◽  
Pollen Presentation

The secondary presentation of pollen consists of a foral mechanism where the presentation of pollen occurs in other foral structures in addition to the anther, in order to increase the precision of the dispersion of the pollen by the vectors. This study aims to describe the temporal dynamics of secondary pollen presentation, and morphological and morphometric characteristics in stages of pre- anthesis and anthesis in genotypes of fve natural Heliconia psittacorum populations. For the study of foral morphometry traits of length of the fower, stamen, stigma and height of flament insertion in the petal in bud and fower were measured. The foral morphology of pre-anthesis buds and fowers in anthesis, the presence or absence of characteristics such as herkogamy, region of flament insertion in the petal, region of stylar hairs, and of secondary pollen deposition were evaluated. Treatments of controlled pollinations, self-pollination, geitonogamy, cross-pollination, natural pollination and growth to pollen tube were sampled. Floral herkogamy and pollen transfer to the adhered hairs in the stylar region were clearly observed during anthesis, constituting the frst record of occurrence of secondary pollen presentation in Heliconiaceae. Pollen tube growth was inhibited in the stigmatic, style and basal regions of the pistil. Natural fruiting produced little or no fruit. The positioning of the stamens above the stigma, pollen viability and stigma receptivity during anthesis of H. psittacorum fowers may favor self-pollination. The stylar hairs observed in all H. psittacorum populations’ help in the retention of pollen grains. The low fruiting rate in controlled and natural pollinations suggest that the main propagation form of H. psittacorum in the study areas is based on asexual reproduction.

scholarly journals Effects of herbivory and its timing on reproductive success of a tropical deciduous tree

2020 ◽  
Vol 126 (5) ◽  
pp. 957-969
Author(s):  
Enya N Quiroz-Pacheco ◽  
Francisco Mora ◽  
Karina Boege ◽  
César A Domínguez ◽  
Ek del-Val
Keyword(s):  
Reproductive Success ◽  
Structural Equation ◽  
Structural Equation Models ◽  
Pollen Grains ◽  
Leaf Damage ◽  
Deciduous Tree ◽  
Herbivore Damage ◽  
Male And Female ◽  
Foliar Damage ◽  
The Impact

Abstract Background and Aims The implications of herbivory for plant reproduction have been widely studied; however, the relationship of defoliation and reproductive success is not linear, as there are many interacting factors that may influence reproductive responses to herbivore damage. In this study we aimed to disentangle how the timing of foliar damage impacts both male and female components of fitness, and to assess when it has greater impacts on plant reproductive success. Methods We measured herbivore damage and its effects on floral production, male and female floral attributes as well as fruit yield in three different phenological phases of Casearia nitida (Salicaceae) over the course of two consecutive years. Then we tested two models of multiple causal links among herbivory and reproductive success using piecewise structural equation models. Key Results The effects of leaf damage differed between reproductive seasons and between male and female components of fitness. Moreover, the impact of herbivory extended beyond the year when it was exerted. The previous season’s cumulated foliar damage had the largest impact on reproductive characters, in particular a negative effect on the numbers of inflorescences, flowers and pollen grains, indirectly affecting the numbers of infructescences and fruits, and a positive one on the amount of foliar damage during flowering. Conclusions For perennial and proleptic species, the dynamics of resource acquisition and allocation patterns for reproduction promote and extend the effects of herbivore damage to longer periods than a single reproductive event and growing season, through the interactions among different components of female and male fitness.

scholarly journals Electrostatic Processes Underlying Natural and Mechanized Transfer of Pollen

1998 ◽  
Author(s):  
Edward Law ◽  
Samuel Gan-Mor ◽  
Hazel Wetzstein ◽  
Dan Eisikowitch
Keyword(s):  
Electric Fields ◽  
Pollen Viability ◽  
Pollen Grains ◽  
Basic Knowledge ◽  
Pollen Deposition ◽  
Average Charge ◽  
Pollen Transfer ◽  
Transfer Vectors ◽  
Pollination Systems ◽  
Relaxation Characteristics

The project objective was to more fully understand how the motion of pollen grains may be controlled by electrostatic forces, and to develop a reliable mechanized pollination system based upon sound electrostatic and aerodynamic principles. Theoretical and experimental analyses and computer simulation methods which investigated electrostatic aspects of natural pollen transfer by insects found that: a) actively flying honeybees accumulate ~ 23 pC average charge (93 pC max.) which elevates their bodies to ~ 47 V likely by triboelectrification, inducing ~ 10 fC of opposite charge onto nearby pollen grains, and overcoming their typically 0.3-3.9 nN detachment force resulting in non-contact electrostatic pollen transfer across a 5 mm or greater air gap from anther-to-bee, thus providing a theoretical basis for earlier experimental observations and "buzz pollination" events; b) charge-relaxation characteristics measured for flower structural components (viz., 3 ns and 25 ns time constants, respectively, for the stigma-style vs. waxy petal surfaces) ensure them to be electrically appropriate targets for electrodeposition of charged pollen grains but not differing sufficiently to facilitate electrodynamic focusing onto the stigma; c) conventional electrostatic focusing beneficially concentrates pollen-deposition electric fields onto the pistill tip by 3-fold as compared to that onto underlying flower structures; and d) pollen viability is adequately maintained following exposure to particulate charging/management fields exceeding 2 MV/m. Laboratory- and field-scale processes/prototype machines for electrostatic application of pollen were successfully developed to dispense pollen in both a dry-powder phase and in a liquid-carried phase utilizing corona, triboelectric, and induction particulate-charging methods; pollen-charge levels attained (~ 1-10 mC/kg) provide pollen-deposition forces 10-, 77-, and 100-fold greater than gravity, respectively, for such charged pollen grains subjected to a 1 kV/cm electric field. Lab and field evaluations have documented charged vs. ukncharged pollen deposition to be significantly (a = 0.01-0.05) increased by 3.9-5.6 times. Orchard trials showed initial fruit set on branches individually treated with electrostatically applied pollen to typically increase up to ~ 2-fold vs. uncharged pollen applications; however, whole-tree applications have not significantly shown similar levels of benefit and corrective measures continue. Project results thus contribute important basic knowledge and applied electrostatics technology which will provide agriculture with alternative/supplemental mechanized pollination systems as tranditional pollen-transfer vectors are further endangered by natural and man-fade factors.

scholarly journals Determination of Blooming, Pollen and Fruit Set Characteristics in Punica granatum

2019 ◽  
Vol 47 (4) ◽  
pp. 1258-1263
Author(s):  
Deniz AKSOY ◽  
Zeynel DALKILIC
Keyword(s):  
Fruit Set ◽  
Pollen Viability ◽  
Pollen Grains ◽  
Punica Granatum ◽  
Digital Object Identifier ◽  
Self Pollination ◽  
Beginning Of Flowering ◽  
Male Flowers ◽  
In The Beginning

The objective of this study was to investigate flowering, pollen, and fruit set characteristics of locally registered pomegranate cultivars between two consecutive years. ‘Dr. Ercan 35’, ‘Efenar 35’, ‘Kamilbey 35’, and ‘Tezeren 35’ cultivars have been developed by cross-breeding programs. Open-, cross-, and self-pollination studies were performed with these cultivars using three trees in each replicate in the field. Number of anthers per flower, number of pollen grains per anther, viability, and germination tests were conducted in the laboratory. Fruit set ratio of self-pollinated combinations were lower than open-pollination. The fruit set ratio from self-pollination was obtained from ‘Dr. Ercan’ (60.3%), ‘Efenar 35’ (62.4%), ‘Kamilbey 35’ (50.5%), and ‘Tezeren 35’ (25.2%). The highest fruit set ratio (49.7%) was obtained from ‘Kamilbey 35’ × ‘Dr. Ercan 35’ combination. The highest number of characteristics was as follows: ‘Tezeren 35’ (402 anthers/hermaphrodite flowers), ‘Kamilbey 35’ (8550 pollen/anther, male flowers in the beginning of flowering), ‘Efenar 35’ (84.7% pollen viability, hermaphrodite flowers), ‘Kamilbey 35’ (71.2%, pollen germination, hermaphrodite flowers). In conclusion, at least one, two or more, pollinator cultivars are necessary for commercial plantations using with these recently released pomegranate cultivars.   ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 4, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********

scholarly journals Pollination of Grewia asiatica (Malvaceae) by Megachile cephalotes (Hymenoptera: Megachilidae): Male vs. Female Pollination

Sociobiology ◽  
2019 ◽  
Vol 66 (3) ◽  
pp. 467 ◽  
Author(s):  
Asif Sajjad ◽  
Waseem Akram ◽  
Sajjad Ali ◽  
Muhammad Aslam Farooqi ◽  
Ghulam Mujtaba ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Pollen Grains ◽  
Pollen Deposition ◽  
Special Focus ◽  
Future Studies ◽  
Post Harvest ◽  
Visitation Frequency ◽  
Harvest Intervals ◽  
Stay Time ◽  
Sunlight Intensity

Phalsa, Grewia asiatica is a multi-purpose crop while cross-pollination can significantly improve its reproductive success. Megachile bees (Megachilidae) are the most important group of pollinators of G. asiatica. In this study we observed the foraging behavior of Megachile cephalotes and its ultimate impact on reproductive success of phalsa at Bahawalpur (Punjab), Pakistan. Although visitation rate and stay time were statistically similar in both the sexes but visitation frequency (2.06±0.14 individuals/120 seconds) and pollen deposition (39.35±3.17 pollen grains /stigma/visit) of females were significantly higher than that of males (0.44±0.06 individuals/120 seconds and 12.05±1.19 pollen grains/stigma/visit, respectively). The environmental factors (i.e. ambient temperature, relative humidity, sunlight intensity and wind speed) greatly influenced -either positively or negatively- both the sexes (Pearson’s correlation). Female pollinated fruits were significantly greater in weight (0.41±0.017 g) followed by open (0.31±0.012 g) and male (0.27±0.011 g) pollinated fruits. Percent weight loss remained significantly lower in female pollinated fruits than open and male pollinated fruits until12 hours after harvest. Fruit wrinkling significantly increased with the increase in post-harvest intervals in open, female and male pollinated fruits while fruit color changed only in female pollinated fruits. The results of present study suggest female M. cephalotes as the efficient pollinators of G. asiatica in terms of it reproductive success and post-harvest parameters. Future studies should focus biology and ecology of M. cephalotes with special focus on its artificial nesting.

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.

Kochia (Kochia scoparia) Pollen Dispersion, Viability and Germination

Weed Science ◽  
1994 ◽  
Vol 42 (4) ◽  
pp. 548-552 ◽  
Author(s):  
Dawit Mulugeta ◽  
Bruce D. Maxwell ◽  
Peter K. Fay ◽  
William E. Dyer
Keyword(s):  
Relative Humidity ◽  
Pollen Viability ◽  
Pollen Grains ◽  
Pollen Deposition ◽  
Kochia Scoparia ◽  
Tetrazolium Chloride ◽  
Pollen Dispersion ◽  
Prevailing Wind Direction ◽  
Fallow Field ◽  
Agar Media

Kochia pollen dispersion was measured during 24 and 48 h periods from a kochia population in an 8- by 10-m area in the center of a 1.6 ha fallow field. Pollen counts from traps at 50- and 100-cm heights declined rapidly with increasing distance from the pollen source. Pollen deposition was highest along the prevailing wind direction: up to 23 pollen grains cm–2were recovered 50 m from the pollen source along the southeast (SE) vector. Nonlinear regression analysis of pollen deposition along the SE vector was used to estimate that 99.9% of shed pollen would be deposited within 154.4 m of the source. Viability of pollen from greenhouse- and field-grown plants was measured using staining and germination assays. of four pollen stains tested, only 1,2,3-triphenyl tetrazolium chloride gave consistent results and did not stain heat-killed pollen. Depending on environmental conditions, kochia pollen remained viable from less than 1 d to 12 d. Length of kochia pollen viability was shortest under high temperatures (22 and 28 C) and low relative humidity (7 and 32%). Less than 0.5% germination was observed in 1.1% agar media with various additions; however, up to 17.8% germination was observed after incubation at 28 C in 100% relative humidity.

scholarly journals Why be thrifty? Sex-specific heterothermic patterns in wintering captive Microcebus murinus do not translate into differences in energy balance.

2021 ◽  
Author(s):  
Aude Noiret ◽  
Caitlin Karanewsky ◽  
Fabienne Aujard ◽  
Jeremy Terrien
Keyword(s):  
Reproductive Success ◽  
Caloric Restriction ◽  
Energy Savings ◽  
Natural Populations ◽  
Individual Variability ◽  
Microcebus Murinus ◽  
Similar Response ◽  
Climate Conditions ◽  
Positive Effects ◽  
The Impact

The physiological mechanisms of the responses toward stressors are the core of ecophysiology studies to understand the limits of an organism s flexibility and better predict the impact of environmental degradation on natural populations. However, little information is available when we question inter-individual variability of these physiological responses, even though they can be particularly important. Some observations of intersexual differences in heterothermy raised the question of a difference in energy management between sexes. Here we assess male and female differences in a mouse lemur model (Microcebus murinus), a highly seasonal Malagasy primate, studying their physiological flexibility toward caloric restriction, and examining the impact on their reproductive success. These animals are adapted for naturally changing food availability and climate conditions, and can express deep torpor, allowing them to spare their energy expenses over the dry and cold season. We monitored body mass and body temperature on 12 males and 12 females over winter, applying a chronic 40% caloric restriction to 6 individuals of each group. Our results showed variability of Tb modulations throughout winter and in response to caloric treatment depending on the sex, as females entered deep torpor regardless of food restriction, while only CR males had a similar response. The use of deep torpor, however, did not translate into better body condition either in females, or in response to CR, and did not clearly affect reproductive success. The favorable captive context potentially buffered the depth of torpor and minimized the positive effects of using torpor on energy savings. However, our results may emphasize the existence of other benefits of heterothermic responses than fat reserves.

scholarly journals Effectiveness of habitat management for improving grey partridge populations: a BACI experimental assessment

2012 ◽  
Vol 35 (2) ◽  
pp. 405-413
Author(s):  
E. Bro ◽  
◽  
P. Mayot ◽  
F. Reitz ◽  
◽  
...  
Keyword(s):  
Reproductive Success ◽  
Habitat Management ◽  
Field Experiments ◽  
Point Of View ◽  
Food Supplementation ◽  
Feeding Intensity ◽  
Grey Partridge ◽  
Positive Effects ◽  
Pair Density ◽  
The Impact

We assessed the impact of field division (4 m bare ground strips within wheat fields) and food supplementation (supplied through grain feeders) on grey partridge Perdix perdix L. populations using six–year ‘before–after’/’control–impact’ (BACI) experiments. We did not detect any convincing positive effects of either of these two schemes on partridge pair density and reproductive success. Increases in pair densities were similar on managed and control areas, and contrasting results were found between some sites. No consistent pattern was observed between reproductive success and feeding intensity. Our studies highlight the need for field experiments at farm–scale to test the effectiveness of management measures. We conclude that, in the context in which they are applied, management techniques directed towards increasing partridge density do not systematically provide the desired outcome. We develop our point of view about management in the Discussion.

Effect of flower density on pollen viability and fruit set of Calceolaria tripartita Ruiz &Pav. (Scrophulariaceae) in Darjeeling Himalaya

2017 ◽  
Vol 8 ◽  
Author(s):  
Ashoke Bhattacharya
Keyword(s):  
Pollen Fertility ◽  
Fruit Set ◽  
Pollen Viability ◽  
Pollen Grains ◽  
Ratio Estimation ◽  
Darjeeling Himalaya ◽  
Flower Density ◽  
The Impact ◽  
East West ◽  
Pollen Biology

<p>There are many populations in a 16 km east-west distribution and populations are usually small with fewer than 100 plants/clumps. The pollen biology in terms of pollen production, pollen-ovule ratio estimation, pollen viability and pollen fertility was studied to determine the impact of plant and flower density on pollen viability and fruit set of <em>Calceolaria tripartita</em> Ruiz &amp;Pav. (Scrophulariaceae) in Darjeeling Himalaya. It is revealed that higher the density of the plants and flowers, the productivity of pollens and ovules and the viability and fertility of pollen grains become higher showing a positive correlation between plant-flower density vs. pollen biology. Fruit set is higher in high dense flowering site than low ones which might be due to higher pollen fertility rate, low sterility and greater number of pollen load upon stigma. Thus, it reflects that plant and flower density has a crucial role upon the reproductive fitness of this taxon.</p>

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