Hand Pollination Research Articles

The influence of pollinators and seed predation on seed production in dwarf grassland Protea “sugarbushes” (Proteaceae)

Flowers of many plant species are visited by both birds and insects, making it necessary to establish their relative contributions to seed set. In Protea, available evidence points to an overwhelming preponderance of bird-pollination systems in the genus, but the scented flowers of several dwarf grassland “sugarbush” species suggest that some Protea species may be adapted for insect pollination. In this study, we used both selective exclusion of vertebrates and complete exclusion of all visitors to investigate whether the insects that visit the scented flowerheads of three Protea species (Protea dracomontana, Protea simplex and Protea welwitschii) in KwaZulu-Natal, South Africa contribute to seed production. We also performed supplemental hand pollinations to test for pollen limitation. Seed set was generally higher in inflorescences subjected to vertebrate exclusion than in those from which all visitors were excluded, suggesting that fertile cross-pollen was deposited by insects, but these differences were slight because of high levels of self-fertilization in the study species. Pollen deposition and pollen tube growth were similar for vertebrate-excluded and open-pollinated inflorescences. Supplemental hand-pollination treatments revealed that seed set in P. simplex and P. welwitschii was not pollen-limited. Overall seed set was low, typical of the family Proteaceae, and infructescences were highly predated by lepidopteran larvae. We conclude that insects are likely to contribute to seed set of the study species, but further studies using molecular markers are required to establish the actual level of insect-mediated outcrossing.

The evolution of pollen germination timing in flowering plants: Austrobaileya scandens (Austrobaileyaceae)

The pollination to fertilization process (progamic phase) is thought to have become greatly abbreviated with the origin of flowering plants. In order to understand what developmental mechanisms enabled the speeding of fertilization, comparative data are needed from across the group, especially from early-divergent lineages. I studied the pollen germination process of Austrobaileya scandens, a perennial vine endemic to the Wet Tropics area of northeastern Queensland, Australia, and a member of the ancient angiosperm lineage, Austrobaileyales. I used in vivo and in vitro hand pollinations and timed collections to study development from late pollen maturation to just after germination. Then I compared the contribution of pollen germination timing to progamic phase duration in 131 angiosperm species (65 families). Mature pollen of Austrobaileya was bicellular, starchless and moderately dehydrated-water content was 31.5 % by weight and volume increased by 57.9 % upon hydration. A callose layer in the inner intine appeared only after pollination. In vivo pollen germination followed a logarithmic curve, rising from 28 % at 1 hour after pollination (hap) to 97 % at 12 hap (R(2) = 0.98). Sufficient pollen germination to fertilize all ovules was predicted to have occurred within 62 min. Across angiosperms, pollen germination ranged from 1 min to >60 h long and required 8.3 ± 9.8 % of the total duration of the progamic phase. Pollen of Austrobaileya has many plesiomorphic features that are thought to prolong germination. Yet its germination is quite fast for species with desiccation-tolerant pollen (range: <1 to 60 h). Austrobaileya and other early-divergent angiosperms have relatively rapid pollen germination and short progamic phases, comparable to those of many insect-pollinated monocots and eudicots. These results suggest that both the pollen germination and pollen tube growth periods were marked by acceleration of developmental processes early in angiosperm history.

Indication of Xenia Effect on Cocoa (Theobroma cacao L.)

Cocoa plant generally is classified as cross pollinated plant and self-incompatible plant, then there is indication the presence of pollen influence on cocoa bean quality. This study was aimed to determine the effect of pollen sources (xenia) on the colour and size characters of fresh cocoa beans (Theobroma cacao L.). This study was done on two stages. The first stage, a treatment of hand pollination of cocoa clones of DR 1, DR 2, DRC 16, KW 264 and ICCRI 03 was applied in this study. There were five treatments of hand pollination: DR 2 x DR 1, DRC 16 x DR 1, DRC 16 X KW 264, DR 1 x DR 2 and ICCRI 03 x DRC 16. Each treatment was repeated four times. Colour parameters of fresh cocoa beans were observed. The second stage consisted of nine hand pollination combinations: TSH 858 x Sulawesi 1, TSH 858 x ICCRI 03, TSH 858 x KW 264, TSH 858 x KW 570, TSH 858 x Sca 6, Sulawesi 1 x TSH 858, Sulawesi 1 x Sca 6, Sulawesi 1 x KW 570 and KW 516 x Sca 6. Each treatment was repeated three times. Size parameters of fresh cocoa pod and beans were observed. The result showed that hybridization using pollen source from bulk cocoa and DR 1 contributed dark colour to fineflavored cocoa. This colour contribution was showed by the increase in the dark fresh percentage of cocoa beans. On the other hand, hybridization using pollen source from fine-flavored cocoa contributed white and pale colour to bulk cocoa. This light colour contribution was showed by the decrease in the percentage of the dark fresh beans. Xenia effect occured on pod weight, pod length, pod girth, bean weight with pulp per pod and bean weight without pulp per pod which was shown by the hybridization with TSH 858 as female parent and weight bean without pulp per pod shown by the hybridization with THS 858 and Sulawesi 1 as female parent. Key word: Xenia, fresh beans colour, fresh beans size, Theobroma cacao L.

Mating system and female reproductive success of the endemic, epiphytic Prosthechea aff. karwinskii (Orchidaceae)

Prosthechea aff. karwinskii (Mart.) Soto Arenas &amp; Salazar (unpublished name) is an endemic Mexican epiphytic orchid with a restricted distribution. It occurs in deciduous oak forests, particularly on Quercus deserticola in the northern portion of Michoacán state. Due to their ornamental uses, this and other orchid species have been heavily collected from their natural populations. Learning about the reproductive biology of this species is important, as we may gain knowledge about the probable repercussions of overcollecting on their genetics and ecology. This will be a useful tool for the management and conservation of the species. The objectives were to 1) study the mating system of P. aff. karwinskii, 2) determine if the species requires an external pollinating agent for sexual reproduction, and 3) evaluate female reproductive success of this species. Exclusions (150) were made before anthesis. Once the flowers opened, we applied four pollination treatments: manual selfing, outcrossing, spontaneous autogamy, and open pollination. We subsequently quantified the production of fruits and viability of the seeds. Preliminary results showed that outcrossing and selfing treatments exhibited statistically higher fruit set than spontaneous autogamy and open pollination treatments, meaning that P. aff. karwinskii has the capability to reproduce via self-pollination. Prosthechea aff. karwinskii is pollinator-dependent for sexual reproduction, taking into account that the spontaneous autogamy treatment showed nil fruit production. Female reproductive success in open pollinated flowers was lower compared to fruit set of hand pollination treatments. This indicates that this species, as other species of tropical orchids, is pollination-limited.

Discrimination of almond self compatible genotypes by different methods in a breeding program in Iran

Self-incompatibility is one of the most important difficulties in almond production, which reduces fruit set dramatically and makes orchard management difficult. Therefore, producing breeding self-compatible almond genotypes is of great importance. In this research work, the growth of pollen tube was studied in 38 genotypes obtained after crossing “Touno” (male parent) with “Shahrood 12” (female parent). To study fruit set during years 2009 and 2010, four branches of each genotype were bagged in stage D. Results showed that some genotypes were self- compatible. On the other hand, cross-pollination increased the fruit set of self-compatible genotypes. For microscopic study, flowers were harvested at 24, 72 and 120 h after hand pollination. Results of two years (2009 and 2010) study indicated that 24 and 72 h were not enough for the pollen tube to reach the base of style, whereas 120 h were an appropriate time. To double check the status of self-compatible those genotypes and to determinate the situation of genotypes recognized as doubtful by the use of fluorescent microscopy, PCR reaction was carried out with specific primers of SfF and SfR. PCR results confirmed the situation of self-compatible genotypes. In addition, it indicated that five doubtful genotypes were self-compatible. However, another four genotypes were recognized as self-incompatible. In general, 50% of genotypes were realized as self-compatible and another 50% were self-incompatible. Key words: Self compatibility, self-incompatibility, cross compatibility, self pollination, fruit set, fluorescent microscopy, polymerase chain reaction (PCR).

Hybridization and asymmetric introgression between Cypripedium tibeticum and C. yunnanense in Shangrila County, Yunnan Province, China

Hybridization and introgression are thought to be important for speciation and adaptation in many plants. However, little is known about the hybridization and introgression among Cypripedium species. To investigate the evidence for hybridization and the pattern of introgression between Cypripedium yunnanense and C. tibeticum in Shangrila County, Yunnan Province, China, morphological characters and amplified fragment length polymorphism (AFLP) data for both the species and their putative hybrids were studied. Hand pollination was also performed to verify the crossability of the putative parents. Principal coordinate analysis based on morphological characters and the AFLP data suggested that the putative hybrids were true hybrids of these two Cypripedium species. Analysis with the NewHybrids software indicated that the putative hybrids were F1 generation individuals and backcrosses to C. yunnanese, but no F2 generation was found. Analysis with the Structure software demonstrated asymmetric introgression from C. tibeticum to C. yunnanense. We conclude that natural hybridization and introgression can occur between these two species and that in situ conservation of the parental species is required before fully assessing the evolutionary potential of hybrids.

Sapromyiophily in the native orchid, Bulbophyllum variegatum, on Réunion (Mascarene Archipelago, Indian Ocean)

Abstract:Orchid species are well known for their highly specialized pollinator interactions. To better understand the reproductive biology of the tropical epiphytic orchid Bulbophyllum variegatum on Réunion, we investigated the floral morphology, breeding system, pollinator diversity, floral scent profile and fruiting success of about 30 individuals in three natural populations during two consecutive flowering seasons. Controlled hand-pollination experiments in two populations showed that the species is self-compatible, but requires pollinator service to achieve reproduction. Videotape pollinator observations were conducted during two flowering seasons for 56 h and revealed that B. variegatum is pollinated by a single species of fly from the Platystomatidae. This fly seems to be attracted by the unpleasant scent produced by the flowers, and does not receive any reward after achieving pollination. In addition, no egg-laying behaviour was observed. Bulbophyllum variegatum thus exhibits a typical sapromyiophilous pollination syndrome which constitutes the first proven case of sapromyiophily within the genus Bulbophyllum on the Mascarene Archipelago. Hand pollinations further showed that fruit set was not significantly higher for flowers that received outcross pollen than for those that were self-crossed (53% and 44% respectively). Fruit sets under natural conditions were significantly different among populations, ranging from 0.5% to 24.3%. This low fruit production is likely due to infrequent pollinator visits, particularly in disturbed forests where the pollinator has never been observed.

Self-compatibility and plant invasiveness: Comparing species in native and invasive ranges

A longstanding hypothesis (“Baker's rule”) is that plant invasiveness is facilitated by floral self compatibility rather than self incompatibility. Extending this idea, invasive species whose individuals vary in degree of self compatibility within the native range might be self compatible in invading or weedy populations, due to natural selection on the mating system. We compared mating system between native and invasive ranges for two major world invasives, one annual (Echium plantagineum) and one perennial (Solanum elaeagnifolium). For an additional annual species (Centaurea solstitialis) we compared non-weedy and weedy populations in the native range. No species was strongly spontaneously self pollinating, but the degree of self compatibility after hand pollination varied dramatically. Both annuals were self incompatible in native or non-weedy populations but self compatible in invasive or weedy ones; the reverse was true for the perennial. Individuals within populations of all three species also varied in their degree of self compatibility, suggesting a basis for natural selection, and populations of the same species sharing a status (native/non-weedy, invading/weedy) varied in average self compatibility. These results support the hypothesis that differential selection of progeny during invasion can result in self-compatible populations derived from ancestrally self-incompatible ones, but that this process may be less important in perennial species, which experience multiple opportunities for sexual reproduction. Overall, however, mating system may not operate alone and its contributions to invasiveness may be conditional on other attributes of a species including physiology, morphology, and life history.

Pollen limitation and variation in floral longevity in gynodioecious Potentilla tanacetifolia

Abstract Pollination limitation is common in flowering plants and is thought to be a factor driving the evolution of floral traits. The plasticity of floral longevity to pollination may be an adaptation of plants to pollen limitation. However, this adaptation is less critical in short-lived flowers. To evaluate pollen limitation and the plasticity of floral longevity to pollination in Potentilla tanacetifolia, a gynodioecious herb with short-lived flowers, we analyzed its breeding system, tested sex-differential pollen limitation, and compared variations in floral display size in natural populations in Duolun County, Inner Mongolia, China. Hand pollination experiments and pollinator exclusion treatments revealed that P. tanacetifolia is self-compatible and non-autonomously apomictic and shows sex-differential pollen limitation. The plasticity of floral longevity to pollination was observed; the floral duration of female plants was prolonged by approximately 3–4 hours with pollination exclusion treatment. Moreover, the percentage of flowers displayed on female plants during pollination exclusion treatment was significantly higher than that during natural pollination. Under natural pollination conditions, the percentage of flowers displayed on female plants was significantly higher than on hermaphrodite plants. Furthermore, approximately 50% of the pollen grains spread out of the anthers of hermaphrodite flowers within 2 h of anthesis; the number of pollen grains adhering to the stigmas of hermaphrodite flowers was significantly higher than that adhering to female flowers when flowers shed their petals. These results indicate that variation in floral longevity may be an adaptive strategy to pollination conditions for gynodioecious P. tanacetifolia.

Evolutionary genetics of an S-like polymorphism in Papaveraceae with putative function in self-incompatibility.

Background Papaver rhoeas possesses a gametophytic self-incompatibility (SI) system not homologous to any other SI mechanism characterized at the molecular level. Four previously published full length stigmatic S-alleles from the genus Papaver exhibited remarkable sequence divergence, but these studies failed to amplify additional S-alleles despite crossing evidence for more than 60 S-alleles in Papaver rhoeas alone.Methodology/Principal FindingsUsing RT-PCR we identified 87 unique putative stigmatic S-allele sequences from the Papaveraceae Argemone munita, Papaver mcconnellii, P. nudicuale, Platystemon californicus and Romneya coulteri. Hand pollinations among two full-sib families of both A. munita and P. californicus indicate a strong correlation between the putative S-genotype and observed incompatibility phenotype. However, we also found more than two S-like sequences in some individuals of A. munita and P. californicus, with two products co-segregating in both full-sib families of P. californicus. Pairwise sequence divergence estimates within and among taxa show Papaver stigmatic S-alleles to be the most variable with lower divergence among putative S-alleles from other Papaveraceae. Genealogical analysis indicates little shared ancestral polymorphism among S-like sequences from different genera. Lack of shared ancestral polymorphism could be due to long divergence times among genera studied, reduced levels of balancing selection if some or all S-like sequences do not function in incompatibility, population bottlenecks, or different levels of recombination among taxa. Preliminary estimates of positive selection find many sites under selective constraint with a few undergoing positive selection, suggesting that self-recognition may depend on amino acid substitutions at only a few sites.Conclusions/SignificanceBecause of the strong correlation between genotype and SI phenotype, sequences reported here represent either functional stylar S-alleles, tightly linked paralogs of the S-locus or a combination of both. The considerable complexity revealed in this study shows we have much to learn about the evolutionary dynamics of self-incompatibility systems.

Production and characterization of interspecific hybrids between Asparagus kiusianus Makino and A. officinalis L.

Interspecific hybridization is a useful technique to introduce characteristics from wild species into crops. Garden asparagus (Asparagus officinalis, 2n = 2x = 20) is an economically important vegetable that is native to the Mediterranean region but widely cultivated in many countries. The genus Asparagus is comprised of over 100 species. Asparagus kiusianus (2n = 2x = 20) is a wild asparagus species endemic to Japan. This species occurs on the coast and is likely to be a salt-resistant species. Although the geographic distribution of these two species is not close, molecular phylogenetic analysis demonstrated that these two species are closely related. In this study, a reciprocal cross between A. officinalis and A. kiusianus was carried out by hand pollination, and progeny were obtained from both crossings. These progeny exhibited a morphologically intermediate phenotype in terms of flower shape, and restriction fragment length polymorphism analysis confirmed that these were indeed interspecific hybrids. The interspecific hybrids were fertile, and backcross progeny with garden asparagus was also generated. These interspecific hybrids are expected to supply novel traits to garden asparagus.

Limited pollen-mediated dispersal and partial self-incompatibility in the rare ironstone endemic Tetratheca paynterae subsp. paynterae increase the risks associated with habitat loss

Patterns of mating and dispersal are key factors affecting the dynamics, viability and evolution of plant populations. Changes in mating system parameters can provide evidence of anthropogenic impacts on populations of rare plants. Tetratheca paynterae subsp. paynterae is a critically endangered perennial shrub confined to a single ironstone range in Western Australia. Mining of the range removed 25% of plants in 2004 and further plants may be removed if the viability of the remaining populations is not compromised. To provide baseline genetic data for monitoring mining impacts, we characterised the mating system and pollen dispersal over two seasons in T. paynterae subsp. paynterae and compared mating system parameters with two other ironstone endemics, T. paynterae subsp. cremnobata and T. aphylla subsp. aphylla that were not impacted by mining. T. paynterae subsp. paynterae was the only taxon showing evidence of inbreeding (t m = 0.89), although hand pollination revealed pre-zygotic self-incompatibility limits the production of seed from self-pollen. In a year of lower fruit set (2005), the estimate of correlated paternity increased from 20 to 35%. Direct estimates of realised pollen dispersal, made by paternity assignment in two small populations where all adult plants were genotyped, revealed a leptokurtic distribution with 30% of pollen dispersed less than 3 m and 90% less than 15 m. Restricted pollen dispersal maintains the strong genetic structuring of the adult populations in succeeding generations. As a consequence of preferential outcrossing, any reduction in effective population size, flowering plant density and/or the abundance and activity of pollinators may impact negatively on population viability through reduced seed set, increased inbreeding and increased correlated paternity.

The cost of being specialized: Pollinator limitation in the endangered geophyte Brunsvigia litoralis (Amaryllidaceae) in the Cape Floristic Region of South Africa

The impacts of habitat fragmentation and reduced population sizes on ecological processes deserve more attention. In this study we examine pollination in rural and urban populations of Brunsvigia litoralis (Amaryllidaceae), an endangered endemic and a flagship species for plant conservation in South Africa. B. litoralis has flowers conforming to the bird-pollination syndrome, but the only flower visitor at the urban sites, the Greater Double-collared Sunbird ( Cinnyris afra) (1.6 visits/flower/hour), is unable to access the nectar in the usual way due to a long perianth tube (38.8 mm) and resorts to robbing. Supplemental hand pollination was used to test for pollen limitation of seed set at the urban sites flowers were pollen-supplemented. Seed set in supplemented plants increased by more than an order of magnitude relative to controls. The longer-billed Malachite Sunbird ( Nectarinia famosa) was observed as the sole pollinator of B. litoralis at the rural site where seed set was significantly higher. Although B. litoralis plants are long lived, the absence of pollinators in these urban fragments might place populations at an extinction risk.

Cytomorphological and molecular characterization of interspecific F1 hybrid of Momordica dioica Roxb. Momordica subangulata subsp. renigera (G. Don) de Wilde

Interspecific hybrid (F1) between spine gourd (Momordica dioica) and teasle gourd (Momordicasubangulata Blume subsp. Renigera (G. Don) WJJ de Wilde) produced through bagging and hand pollination showed vigorous growth habit with less fertility. Morphological parameters along with meiotic, mitotic chromosome behaviors and Randomly Amplified Polymorphic DNA (RAPD) analysis, confirmed interchanges of genetic characters in the new hybrids. The interspecific hybrid showed a vigorous foliage with intermediate flower characters than that of parental species. Self pollination and backcrossing of F1plants to either parent confirmed presence of both male and female sterility, that might be due to improper meiotic chromosome pairing. The characters like petal spot and time of anthesis (early morning) were similar to that of pollen parent while the diameter and size of leaves and flowers, pedicel length and plant growth were intermediate as compared to parents. Somatic chromosome analysis revealed 2n = 28 in M.dioica – the female parent, 2n = 56 in M. subangulata ssp. renigera - the male parent and 2n = 42 in F1hybrid of M. dioica × M. subangulata ssp. renigera. RAPD analysis of both the parents and F1 hybrid confirmed more genetic affinity (60.95%) with female parent than the male parent (32.35%). Primer specific DNA markers confirmed the introgression of male genetic elements into the newly developed amphidiploids. Incorporation of male specific DNA markers into the F1 hybrid is discussed. Preliminary evaluation indicates that the F1 plants sprouted early, which is lacking in the mother parent and this character could be exploited by restoring of fertility by chromosome doubling. Key words: Momordica, cytomorphology, F1 hybrid, karyotype, RAPD markers.

Pollination biology of Impatiens cuspidata Wight and Arn. (Balsaminaceae), a rare and endemic balsam of the Western Ghats, India

The pollination biology of Impatiens cuspidata, a rare and endemic balsam from the Western Ghats, has been studied with special reference to phenology, pollination, pollen-pistil interactions, breeding experiments and stigma receptivity. It flowers at night between 2330 and 0430 hr; flowering days extend up to 160 days in a year. The anther dehisced one day before anthesis, which confirmed the protandrous condition of the flower. Pollen-ovule ratio was calculated as 1729:1. Hawk moths, honeybees, flies and butterflies are the major pollinators of Impatiens cuspidata. Pollen grains are oval, having an average diameter of 28.24μm. Pollen viability by FCR test confirmed that 82% pollen grains are viable on the day of anthesis. Best pollen germination along with 1636μm tube development was achieved in Brewbakers medium. Stigma was more receptive (up to 80%) on the first day of flower opening. It chiefly reproduced by means of cross pollination, where the fruit set was only 40%, but artificial cross-pollination through xenogamy enhanced fruit set up to 80%. The plant is an obligate out-crosser and self incompatible, as confirmed by various hand pollination experiments. Seed germination in natural and controlled conditions was only 20%. Its dependence on a specialized habitat, bottlenecks in sexual reproduction, low percentage of seed germination and other abiotic factors could be reasons for its limited distribution and endemism.

FLORAL ISOLATION IS THE MAIN REPRODUCTIVE BARRIER AMONG CLOSELY RELATED SEXUALLY DECEPTIVE ORCHIDS

Floral isolation is an important component of pollinator-driven speciation. However, up to now, only a few studies have quantified its strength and relative contribution to total reproductive isolation. In this study, we quantified floral isolation among three closely related, sympatric orchid species of the genus Ophrys by directly tracking pollen flow. Ophrys orchids mimic their pollinators' mating signals, and are pollinated by male insects during mating attempts. This pollination system, called sexual deception, is usually highly specific. However, whether pollinator specialization also conveys floral isolation is currently under debate. In this study, we found strong floral isolation: among 46 tracked pollen transfers in two flowering seasons, all occurred within species. Accounting for observation error rate, we estimated a floral isolation index ≥0.98 among each pair of species. Hand pollination experiments suggested that postpollination barriers were effectively absent among our study species. Genetic analysis based on AFLP markers showed a clear species clustering and very few F(1) hybrids in natural populations, providing independent evidence that strong floral isolation prevents significant interspecies gene flow. Our results provide the first direct evidence that floral isolation acts as the main reproductive barrier among closely related plant species with specialized pollination.

Viabilidade "in vitro" de grãos de pólen de bacurizeiro - Clusiaceae

O bacurizeiro (Platonia insignis Mart.) é uma frutífera nativa da Amazônia, que apresenta alogamia acentuada e autoincompatibilidade esporofítica. A viabilidade in vitro tem sido utilizada para representar a capacidade potencial do pólen em completar o processo de fertilização O objetivo do presente trabalho foi estudar a viabilidade de polens de bacurizeiro por meio da germinação in vitro , por ser esta uma técnica em que o comportamento germinativo é semelhante in vivo . Os ensaios foram conduzidos em laboratório, em um delineamento inteiramente casualizado, analisados em esquema fatorial 2 x 3 x 4, em que: 2=formas de propagação (pé-franco e enxertada); 3=estágios da antese (pré-antese, antese e pós-antese), e 4=concentrações de sacarose (0; 7,5; 10 e 20%), com 10 repetições. Houve diferença significativa na germinação do pólen, sendo que, via polinização manual, o pólen deve ser coletado na antese, enquanto o melhor meio para a germinação in vitro é com 7,5 g de sacarose.

Sexual compatibility and floral biology of some olive cultivars

Pollen tube observation was used to assess the self- and cross-incompatibility of the olive (Olea europaea L.) cultivars ‘Frantoio’, ‘Koroneiki’ and ‘Kalamata’. The pistils were harvested 1 week after hand pollination and stained with 0.1% aniline blue. The styles and ovules were separated, mounted in 80% glycerol and observed under a fluorescence microscope. All the cultivars studied were self-incompatible. ‘Frantoio’ (as a host) was incompatible with ‘Koroneiki’ and ‘Barnea’ but partially compatible with ‘Mission’. ‘Koroneiki’ (as a host) was incompatible with ‘Barnea’ but partially compatible with ‘Frantoio’ and ‘Mission’. ‘Kalamata’ (as a host) was compatible with ‘Barnea’, incompatible with ‘Mission’ and ‘Koroneiki’ in 2004, but partially compatible with them in 2005. The effects of shoot orientation and inflorescence location on inflorescence characteristics were also studied. For each cultivar, inflorescence characteristics in three sections of shoots (top, middle and base) and four sides of the three selected trees (north, south, east and west) were recorded. The statistical analysis showed that basal inflorescences were shorter and with fewer flowers but with the same percentage of perfect flowers. Shoot orientation did not have any influence on these characteristics in any of the cultivars.

Population Status and Reproductive Success of an Endangered Epiphytic Orchid in a Fragmented Landscape

Habitat fragmentation and disturbance are two of the most significant drivers of species extinctions in plant populations. The degree of impact of fragmentation on plant populations depends on the level of specificity of plant‐animal interactions, as well as on the availability of suitable sites for seedling recruitment. In this study, we describe the population density and structure, pollen limitation and reproductive success of the endangered tropical orchid Myrmecophila christinae, an epiphytic species with a specialized pollination system. We surveyed a total of 14 populations located in a fragmented landscape. Seedling density was related to habitat disturbance and host plant density; while density of juveniles was related to density of adults. Adult and total individual densities were related to habitat affectation. We also found that fragments o1ha had significantly fewer seedlings, as well as an over-representation of large adults. On the other hand, fruit production was higher in fragments 410ha, and fruit set was significantly lower in highly disturbed fragments. Hand pollination experiments showed that M. christinae was pollen limited in all the studied populations, suggesting that pollen limitation is unrelated to habitat disturbance. Overall, our results suggest that fragmentation has affected key demographic features of M. christinae, including reproduction and recruitment. Foreign language abstract is available in the online version of this article.

Post-pollination process in a partially self-compatible distylous plant, Primula sieboldii (Primulaceae)

Pollen germination and pollen-tube growth under natural conditions were observed in a population of a distylous species, Primula sieboldii, in which partial self-compatibility has been demonstrated in some long-styled genets. We observed post-pollination processes microscopically in styles collected after self-morph and inter-morph hand pollination (with standardized pollen load on the stigmas) in four genets each from the following three ‘genet types’: self-incompatible long-styled (SI), partially self-compatible long-styled (SC) and self-incompatible short-styled morph genets. Irrespective of the genet type, pollen germination began within 24 h after pollination and tubes of pollen reached to the style base with 48–96 h after inter-morph pollination. Although pollen tubes germinated after self-pollination in the SC genets, the number of germinated pollen tubes was significantly lower than in the case of inter-morph pollination. Few pollen tubes germinated after self-pollination of the SI or short-styled genets. In SC genets, the rate of pollen-tube growth did not differ between self-morph and inter-morph pollination (∼1.9 mm/day). Therefore, differences in self-compatibility between SC and SI genets in P. sieboldii are likely to be attributable to differential pollen germination rates rather than to differential pollen-tube growth rates.