Effect of flowering phenology and habitat on pollen limitation in Erica multiflora

1999 ◽  
Vol 77 (5) ◽  
pp. 734-743 ◽  
Author(s):  
Marc Santandreu ◽  
Francisco Lloret

Pollination can be a major factor influencing reproductive success in plants. Pollination may be influenced by variability in pollen production and vector activity associated with environmental heterogeneity in time and space. These factors were addressed experimentally using hand pollinations of Erica multiflora L., a shrub occurring in the western Mediterranean Basin that exhibits a long flowering period. Variation in pollen limitation was considered three times (early, peak, and late) over the flowering season and between two habitats (shrubland and pine forest). The breeding system and the pollination vectors were also studied by hand pollination and exclusion experiments. Xenogamy and natural pollination (control) treatments produced more seed and fruit set than geitonogamy and autogamy treatments. Insect visitors were less abundant at the end of the flowering period and in the pine forest habitat. Pollen limitation was not different between habitats, but it changed over the flowering period. Fruit set was pollen limited at the early flowering time, when less flowers were available. Both seed and fruit set were pollen limited at the late flowering time, when both flower density and insect visitors were lower. Seed and fruit set were not pollen limited at the peak of the flowering period, but their low values suggest resource limitation associated with a large number of developing fruits.Key words: breeding system, fruit set, hand pollination, insect pollinator, phenology, seed production.

2005 ◽  
Vol 53 (2) ◽  
pp. 163 ◽  
Author(s):  
Bambang Heliyanto ◽  
Erik J. Veneklaas ◽  
Hans Lambers ◽  
Siegfried L. Krauss

The breeding system of Banksia ilicifolia was assessed by performing controlled hand-pollination manipulations on flowers in a natural population in Perth, Western Australia. The percentage of 2000 flowers per treatment converted to fruits and seeds was assessed across 24 recipient plants following (1) self-pollination, (2) local outcross pollination (same population), (3) non-local outcross pollination (pollen sourced from another population 30 km away), (4) unpollinated but bagged flowers and (5) unpollinated, unbagged flowers (natural pollination). The relative performance of the resulting seeds was assessed by seed weight, germination rates and, in an unplanned component of the study, resistance to a fungal pathogen. The percentage of flowers converted to fruits following self-pollination was low (0.9%), but demonstrated self-compatibility. Fruit set following cross-pollinations (3.6 and 3.3% for non-local and local crosses, respectively) was significantly greater than that following self-pollination, open-pollination (0.4%) and autogamous (0.04%) treatments. Low fruit set for open-pollinated flowers, compared with self- and outcross-pollination treatments, suggests pollen limitation. Pollen tubes were observed in 15 and 20% of upper styles of flowers hand-pollinated with self and local outcross pollen, respectively. Seed germination was dependent on the source of pollen, where fewer selfed seeds germinated (37%) than did both non-local and local outcrossed seeds (83 and 91%, respectively). Selfed seedlings showed poorer survival (33.3%) following fungal attack than both non-local and local outcrossed seeds (69.2 and 68.5%, respectively). Only 13% of selfed seeds survived to be 2-month-old seedlings, compared with 63% for non-local and 57% for local outcrossed seeds. Ultimately, for 2000 flowers hand-pollinated with self pollen, only three seedlings survived to an age of 16 weeks, compared with 37 and 45 seedlings for local-cross and non-local cross treatments on 2000 hand-pollinated flowers, respectively. These results indicate that in this population, B. ilicifolia is self-compatible, but preferentially outcrossing, with strong early acting inbreeding depression. Consequently, the breeding system of B. ilicifolia promotes the maintenance of genetic variation and a high genetic load.


2013 ◽  
Vol 29 (4) ◽  
pp. 353-356 ◽  
Author(s):  
Timothée Le Péchon ◽  
Mickaël Sanchez ◽  
Laurence Humeau ◽  
Luc D.B. Gigord ◽  
Li-Bing Zhang

Abstract:The pollination ecology and breeding system of Trochetia granulata (Malvaceae), an endemic tree species from Réunion were studied. In 2010–2011, compatibility studies were conducted on a total of 154 flowers from 35 different individuals using three different hand pollination treatments: (a) autofertility, (b) self-pollination and (c) cross-pollination. During the period, we also studied the pollination ecology of T. granulata. During 48 h of video recordings, we tracked flower visits to T. granulata in six different sites and studied the behaviour of the visitors. The results from the hand-cross experiments show that T. granulata is self-compatible (60.8% fruit set) but cannot produce fruit (5.4% fruit set) without the visit of a pollen vector. During surveys, four different visitors were reported: the introduced honey bee (Apis mellifera), two endemic species of white-eye (Zosterops borbonicus borbonicus and Z. olivaceus) and the endemic Réunion day gecko (Phelsuma borbonica). This study documented a new case of vertebrate-pollination by lizard and birds in an insular context. These interactions might be linked to several uncommon floral traits of Trochetia species.


2001 ◽  
Vol 17 (4) ◽  
pp. 577-592 ◽  
Author(s):  
TRISHA K. CONSIGLIO ◽  
GODFREY R. BOURNE

A pollination and breeding system study was conducted on a neotropical palm, Astrocaryum vulgare, in Guyana, South America, to better understand its reproductive character evolution, and test the predictability of pollination syndromes. The pollination syndrome approach was used because it integrates characteristics of flowers and their pollinators into an evolutionary framework that allowed experimental testing of predictions. The flowers of A. vulgare displayed traits that were typical of both beetle and wind pollination syndromes. The protogynous inflorescences produced heat and odour during nocturnal anthesis, had numerous stamens with copious, light pollen, and were visited by hordes of beetles that used the inflorescences as feeding, mating and oviposition sites. In contrast, some of these features, such as numerous stamens with copious, light pollen, a high pollen to ovule ratio, and no obvious production of visitor rewards, were also typical of the wind pollination syndrome. However, floral rewards appeared to be tissues of the fleshy staminate petals and pollen that were readily devoured by the beetles. In addition to the Coleoptera, insect visitors to A. vulgare inflorescences included several species of Hymenoptera, Diptera and Orthoptera. However, only Nitidulidae and Curculionidae beetles were effective insect pollinators. Pollination treatments showed that wind pollination was possible, but fruit set was significantly higher for female flowers visited by beetles. Although a pollen/ovule ratio of 50 000:1 and outcrossing index confirmed an outcrossing breeding system, pollination experiments suggested that A. vulgare had the potential for self pollination. Therefore, the breeding system might be best classified as facultatively xenogamous (cross fertilizing). The predictive value of potential pollinator agents for A. vulgare was inadequate because its floral traits were indicative of both cantharophilous and anemophilous pollination syndromes.


1990 ◽  
Vol 38 (1) ◽  
pp. 63 ◽  
Author(s):  
RL Goldingay ◽  
RJ Whelan

Three factors that potentially influence fruit set (breeding system, inadequate cross-pollination and variable floral display) were examined for two species of Banksia. Firstly, self-pollination and autogamy treatments failed to produce any fruit in B. spinulosa and produced very few fruit in B. paludosa. This suggests that cross pollen is required to produce the level of fruit set observed in the field. Secondly, when plants were given abundant cross pollen, fruit set was not altered in B. spinulosa but was in B. paludosa. Although the number of follicles per inflorescence was was not different for open- pollinated (control) and manipulated B. paludosa inflorescences, the latter produced twice the proportion of inflorescences with follicles produced by control plants and twice the total number of follicles per plant. Thirdly, larger floral display in open-pollinated B. spinulosa plants was associated with a greater production of fruit. However, larger floral display was not associated with a greater reproductive output in B. paludosa, and we suggest that recurrent pollen-limitation in this species may be responsible for this result.


2021 ◽  
Vol 154 (1) ◽  
pp. 39-48
Author(s):  
Olga V. Nakonechnaya ◽  
Olga G. Koren ◽  
Vasilii S. Sidorenko ◽  
Sergey A. Shabalin ◽  
Tatyana O. Markova ◽  
...  

Background and aims – Interactions of insects with trap flowers of Aristolochia manshuriensis, a relic woody liana with fragmented natural populations from south-eastern Russia, were studied. Pollination experiments were conducted to identify the causes of the poor fruit set in this plant.Material and methods – The study was carried out at two ex situ sites within the natural range of A. manshuriensis in the suburban zone of the city of Vladivostok (Russia). The floral morphology was examined to verify how it may affect the process of pollination in this species. To test for a probability of self-pollination, randomly selected flowers at the female phase of anthesis (day 1 of limb opening) were hand-pollinated with pollen from the same plant. The daily insect visitation was studied. The pollen limitation coefficient and the number of visitors to the flowers were determined. To identify insects that lay eggs on the flowers, the insects were reared from eggs collected from fallen flowers. Both caught and reared insects were identified.Key results – The floral morphology and the colour pattern of A. manshuriensis are adapted to temporarily trap insects of a certain size. The hand-pollination experiment showed that flowers of this plant are capable of self-pollination by geitonogamy and require a pollinator for successful pollination. The positive value (2.64) for the pollen limitation coefficient indicates a higher fruit set after hand-pollination compared to the control without pollination. The number of visitors to the flowers was low (0.17 visitors per flower per day). Insects from three orders were observed on the flowers: Diptera (up to 90.9%), Coleoptera (8.3%), and Hymenoptera (0.8%). Four species of flies (Scaptomyza pallida, Drosophila transversa (Drosophilidae), Botanophila fugax, and Botanophila sp. 1 (Anthomyiidae)) are capable of transferring up to 2500–4000 pollen grains on their bodies and can be considered as pollinators of A. manshuriensis. Data of the rearing experiment indicate that flies of the families Drosophilidae (S. pallida, D. transversa), Chloropidae (Elachiptera tuberculifera, E. sibirica, and Conioscinella divitis), and Anthomyiidae (B. fugax, B. sp. 1) use A. manshuriensis flowers to lay eggs. Beetles were also collected from the flowers, but they were probably not involved in pollination, because no pollen grains were observed on them during our study.Conclusions – Pollinators of A. manshuriensis include mainly Diptera that lay eggs on the flowers. The poor fruit set (2%) in A. manshuriensis is associated with pollen limitation due to the lack of pollinators, as the number of visitors to flowers was extremely low. This may be due to the fact that the flowers of this species are highly specialized on insects of a certain size for pollination.


2009 ◽  
Vol 57 (2) ◽  
pp. 109 ◽  
Author(s):  
Ignasi Bartomeus ◽  
Montserrat Vilà

Many widely known invasive plants are well integrated into native plant–pollinator networks. Typically, these invaders have entomophilous flowers which are visited by a diverse array of pollinators. The type of breeding system and the role that pollination services play in the reproductive success of invasive plants have, however, received little attention. We studied the breeding system and pollen limitation of two entomophilous invasive plants, Carpobrotus affine acinaciformis and Opuntia stricta, in different Mediterranean coastal localities in north-eastern Spain. Both species are, to some degree self-compatible; however, because of frequent visitation, open pollination increased the seed set in both species by at least 50%. Whereas O. stricta showed no pollen limitation, some populations of C. aff. acinaciformis had a lower seed set in open-pollinated flowers than in flowers where supplementary hand-pollination ensured out-crossing. This local pollen limitation in C. aff. acinaciformis could be due to the low efficiency of its visitors (mainly beetles) or its hybrid status. On the basis of previous studies on Carpobrotus sp. hybrid complexes, we suggest that the variability among sites in the seed set of open-pollinated flowers is caused by different degrees of hybrid introgression. Not withstanding, we found the C. aff. acinaciformis seed sets studied were higher than those reported in other regions. Further research is needed to assess the invasion potential of these hybrids in Mediterranean shrublands.


1986 ◽  
Vol 64 (6) ◽  
pp. 1216-1220 ◽  
Author(s):  
Geraldine A. Allen

Male plants of Oemleria cerasiformis have a larger flower display and a longer flowering period than females, and tend to show greater phenological variability. Male inflorescences generally begin to flower sooner than females, but reach their peak and finish flowering later. Their longer blooming period is mainly the result of less synchronous flower opening in males. In both sexes flowering tends to be completed more rapidly in later inflorescences. Fruit set in females is positively correlated with time of flowering (r = 0.313) and inflorescence size (r = 0.421). Hand-pollination of female flowers increased fruit set in most inflorescences, indicating that reproductive success in female O. cerasiformis may be pollen limited.


2010 ◽  
Vol 58 (2) ◽  
pp. 115 ◽  
Author(s):  
Nan Jiang ◽  
Wen-Bin Yu ◽  
Hong-Zhe Li ◽  
Kai-Yun Guan

Flowers of Clematis display showy corollas and diversified shapes. This diversity motivates study of adaptive evolution of flower–pollinator interactions and the functional association between floral traits and plant mating strategies. An integrative study was undertaken, which focused on pollination and reproductive biology of three species representing all three floral types of Clematis. Floral traits were measured, and pollinator assemblages were observed in the field. Bagging, hand-pollination and removal treatments were used to examine breeding systems. The inbreeding depression and pollen limitation were estimated by fruit-set and seed production obtained from pollination treatments. Their floral traits are distinctly different, but are highly associated with pollination syndrome and breeding system. Among them, Clematis akebioides and C. rehderiana may be facultative autogamy (the former was delayed selfing, and the later competing selfing), and C. chrysocoma may be nearly obligate outcrossing. These conclusions are reflected in their stamen-pistil ratios. The levels of inbreeding depression are negatively associated with autonomous self-pollination. Evolution of self-pollination in C. akebioides and C. rehderiana, and pollen limitation in reproduction of the three Clematis species are discussed. This present study, integrating with previous results, will help us to comprehensively recognise and understand the pollination system and reproductive characteristics of Clematis.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12318
Author(s):  
Kenta Watanabe ◽  
Akira Shimizu ◽  
Takashi Sugawara

Distyly is a genetic polymorphism composed of long-and short-styled flowers in a population. The evolutionary breakdown of distyly has been reported in many taxa, and mainly involves a shift toward monomorphism or dioecism. However, a shift toward monoecism has not been reported in distylous species. Psychotria (Rubiaceae), one of the world largest genera, consists of distylous species and their derivatives. In our preliminary study, however, we identified some monoecious individuals in a population of Psychotria manillensis. To understand the breeding system and reproductive biology of P. manillensis, we investigated floral traits, open fruit set, and flower visitors, and performed hand pollination and bagging experiments in five populations of Okinawa and Iriomote islands, Ryukyu Islands, Japan. The populations of P. manillensis were composed mainly of monoecious individuals (54%), followed by female (30%), male (14%), and hermaphroditic (2%) individuals at the time of flower collection. Of the collected flowers, 93% were functionally unisexual (male or female), whereas only 6.5% were perfect (hermaphroditic). However, some individuals changed sex mainly towards increasing femaleness during the flowering period. Moreover, 35% of the studied plants changed their sexual expression over the years. P. manillensis showed self-compatibility and no agamospermy. The fruit set under open pollination varied among populations and years (1.8–21.9%), but it was significantly higher than that of auto-selfing (0.68–1.56%). Wasps and flies were the main flower visitors and probably the main pollinators of the species. In conclusion, P. manillensis was revealed to be polygamous, involving monoecious, female, male, and hermaphroditic individuals. This is the first report of the polygamous breeding system not only in the genus Psychotria, but also in all heterostylous taxa.


2016 ◽  
Vol 64 (2) ◽  
pp. 120 ◽  
Author(s):  
Y. Zhang ◽  
C.L. Zhong ◽  
Q. Han ◽  
Q.B. Jiang ◽  
Y. Chen ◽  
...  

Understanding the reproductive biology of plant species is essential for successful domestication and genetic improvement programs. Casuarina equisetifolia L. is an important plantation species in China and India but information on reproductive biology is limited. To address this issue, grafted ramets of C. equisetifolia were used to study floral biology, breeding system and progeny performance. The female floral longevity of C. equisetifolia reached 28.4 days under non-pollination conditions, which was significantly longer than that of supplementary pollination (5.5 days) and open pollination (12.2 days), implying successful pollination would accelerate senescence of female flowers. Higher fruit set (88.8%) and seed set (35.7%) under supplementary pollination were obtained, compared with 75.9% and 21.7%, respectively, under open pollination, although there were no fruit set and seed set under non-pollination conditions. Pollen limitation was evident based on pollen limitation index (0.39) in seedling plantations of C. equisetifolia. Selfed seedlings had low height and diameter growth in both nursery and field trials and markedly lower survival in field trial, indicating inbreeding depression. Microsatellite-based estimates of selfing rate of open pollinated, monoecious individuals was 42%, suggesting that monoecious C. equisetifolia individuals are self-compatible, and that the breeding system should be classified as facultative xenogamy.


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