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At least 73 records · Page 4Linked to original sources
PubMed2000

Localization of pectins in the pollen tube wall of Ornithogalum virens L. Does the pattern of pectin distribution depend on the growth rate of the pollen tube?

Monoclonal antibodies that recognize pectins were used for the localization of esterified (JIM7) and acidic, unesterified (JIM5) forms of pectin in pollen tube walls of Ornithogalum virens L. (x = n = 3). The results indicated that the distribution of the two forms of pectin in the pollen tube wall depended on the medium (liquid or solid) used for pollen germination. In pollen tubes grown in the liquid medium, the localization of JIM7 was limited to the very tip of the pollen tube, whereas the localization of JIM5 indicated a uniform distribution of unesterified pectins in the very tip of the tube and along the subapical parts of the tube wall. In tubes germinated on the medium stabilized with agar (1-2%) the localization of JIM7 and JIM5 indicated the presence of both forms of pectin in the tube tip and along the whole length of the pollen tube wall in a ring-like pattern. Thus, the localization of esterified pectins in the sub-apical part of the pollen tube wall, below the apex of the tube, is described for the first time. Measurements of the growth rates of pollen tubes growing on the two types of medium indicated that oscillations in tube growth rate occur but these do not coincide with the pattern of pectin distribution in the tube wall. Our results complement the previous data obtained for the localization of JIM5 and JIM7 in pollen tube walls of other plant species. (Y.-Q. Li et al. 1994, Sex Plant Reprod 7: 145-150) and provide new insight into an understanding of the construction of the pollen tube wall and the physiology of pollen grain germination.

Cell Wall↗
PubMed2001

Circular F-actin bundles and a G-actin gradient in pollen and pollen tubes of Lilium davidii.

The distribution of and relationship between F-actin and G-actin were investigated in pollen grains and pollen tubes of Lilium davidii Duch. using a confocal laser scanning microscope after fluorescence and immunofluorescence labeling. Circular F-actin bundles were found to be the main form of microfilament cytoskeleton in pollen grains and pollen tubes. Consistent with cytoplasmic streaming in pollen tubes, there were no obvious F-actin bundles in the 10- to 20-microm tip region of long pollen tubes, only a few short F-actin fragments. Labeling with fluorescein isothiocyanate (FITC)-DNase I at first established the presence of a tip-focused gradient of intracellular G-actin concentration at the extreme apex of the tube, the concentration of G-actin being about twice as high in the 10- to 20-microm region of the tip as in other regions of the pollen tube. We also found that the distribution of G-actin was related negatively to that of the F-actin in pollen tubes of L. davidii. Caffeine treatment caused the G-actin tip-focused gradient to disappear, and F-actin to extend into the pollen tube tip. Based on these results, we speculate that the circular F-actin bundles may be the track for bidirectional cytoplasmic streaming in pollen tubes, and that in the pollen tube tip most of the F-actin is depolymerized into G-actin, leading to the absence of F-actin bundles in this region.

Actins↗
PubMed2006

Distribution of poly(A) RNA and splicing machinery elements in mature Hyacinthus orientalis L. pollen grains and pollen tubes growing in vitro.

The localization of poly(A) mRNA and molecules participating in pre-mRNA splicing, i.e., small nuclear ribonucleoproteins (snRNPs) and the SC35 protein, in mature Hyacinthus orientalis L. pollen grains before anthesis and pollen tubes germinating in vitro were analyzed. The observations indicated a pattern of poly(A) mRNA distribution in mature pollen grains before anthesis which differed from that in germinating pollen grains. Directly before anthesis, poly(A) mRNA was homogeneously distributed throughout the whole cytoplasm, whereas after rehydration, it accumulated at one of the pollen poles. In the pollen tube, poly(A) mRNA was present in the cytoplasm, mainly in the areas beneath the cell membrane and the apical zone. Both before anthesis and during growth of the pollen tube, splicing snRNPs and SC35 protein were localized mainly in the area of the pollen nuclei. During anthesis and just after rehydration of the pollen grains, the pattern of labeling and the levels of the investigated antigens in the areas of the vegetative and generative nuclei were similar. During growth of the pollen tube, a change was observed in the distribution and an increase in the levels of trimethylguanosine snRNA and SC35 protein in the vegetative nucleus. Such a pattern of localization of the splicing machinery suggests resumption of transcription and/or maturation of pre-mRNA in the growing pollen tube.

Guanosine↗
PubMed1991

Clinical and immunologic reactivity of patients allergic to grass pollens and to multiple pollen species. I. Clinical and immunologic characteristics.

The heterogeneity of pollen-allergic individuals is well-known but poorly characterized. Twenty-six patients were studied to characterize their immunologic and clinical patterns. Thirteen patients were allergic only to grass pollens, and 13 other patients were allergic to grass-pollen and other pollen species, including Cupressaceae, plane tree, olive, and Parietaria. The IgE response was assessed by the titration of serum total IgE and orchard grass-specific IgE, as well as by IgE immunoblots to orchard-grass pollens. Clinical reactivity was assessed by nasal challenge with orchard-grass pollens before the pollen season and nasal and bronchial symptom-medication scores between April 1 and June 15. Pollen counts were obtained during this period of survey. Polysensitized patients had significantly increased levels of serum total and specific IgE and a greater heterogeneity of IgE immunoblots, suggesting an enhanced qualitative and quantitative IgE immune response. Polysensitized patients had nasal and bronchial symptoms occurring earlier than grass pollen-allergic individuals, confirming the priming effect caused by other plans flowering with an earlier season for both nasal and bronchial mucosa. Alternatively, the early symptoms may be attributable to the tree pollens or might reflect the higher grass-pollen IgE level in the polysensitized group. Bronchial symptoms appeared a few weeks after nasal symptoms. Nasal challenges were similar in both groups, and the severity of nasal symptoms during the season was not significantly different in both groups, suggesting that the intensity of symptoms is not related to the sensitization nor to the IgE immune response of the subjects.

Adolescent↗
PubMed1992

Identification of common allergenic structures in hazel pollen and hazelnuts: a possible explanation for sensitivity to hazelnuts in patients allergic to tree pollen.

It is known that most patients with type I allergy to tree pollens also suffer from intolerance to nuts. To identify allergenic structures common to hazel pollen and hazelnuts, cross-reactivity of patients' IgE was investigated. With use of immunoblotting,.serum IgE from 25 patients displaying type I allergic reactions to tree pollens and intolerance to hazelnuts (group I) bound to the 17 kd major hazel pollen allergen Cor a I (100%) and to the 14 kd hazel pollen profilin (16%). IgE binding to proteins of comparable molecular weights in hazelnut extracts was found (18 kd and 14 kd), suggesting that proteins similar to Cor a I and hazel profilin might be also expressed in hazelnuts. In contrast, only four sera (22%) from 18 patients (group II) with tree pollen allergy but without any case history of nut hypersensitivity showed IgE binding to the 18 kd protein of hazelnut extract, and none of these sera exhibited IgE reactivity to the hazelnut profilin. To characterize the hazel pollen and hazelnut allergens, purified recombinant Bet v I (major birch pollen allergen) and purified recombinant Bet v II (birch profilin), respectively, were used for IgE-inhibition experiments. Binding of IgE from patients (with nut allergy) to the blotted hazelnut allergens could be blocked by preincubation of patients' sera with the recombinant proteins. Furthermore, the 18 kd protein of hazelnut extract was purified and induced specific release of histamine from basophils of a patient suffering nut hypersensitivity but not from a healthy control donor. A rabbit antibody raised against celery profilin identified the 14 kd proteins in hazel pollen and hazelnuts as profilin. Our experiments suggest a protein with IgE binding properties similar to the major allergens from pollens of hazel, Cor a I, and of birch, Bet v I, as predominant allergens in hazelnuts, and show that the plant pan-allergen profilin can be detected in both hazel pollen and hazelnut extracts.

Allergens↗
PubMed2006

A pollen-specific polygalacturonase from lily is related to major grass pollen allergens.

A pollen-specific gene from lily (Lilium longiflorum Thunb. cv. Snow Queen), designated LLP-PG, was characterized. Southern blots of lily genomic DNA indicated that LLP-PG is a member of a small gene family. A thorough sequence analysis revealed that the LLP-PG gene is interrupted by two introns and encodes a protein of 413 amino acids, with a calculated molecular mass of 44 kDa, and a pI of 8.1. Evaluation of the hydropathy profile showed that the protein has a hydrophobic segment at the N-terminus, indicating the presence of a putative signal peptide. A sequence similarity search showed a significant homology of the encoded protein to pollen polygalacturonases (PGs) from various plant species and to an important group (group 13) of grass pollen allergens. The LLP-PG transcript is pollen-specific and it accumulates only at the latest stage during pollen development, in the mature pollen. In contrast to other "late genes" LLP-PG transcript can neither be induced by abscisic acid (ABA) nor by dehydration. Immunoblot analyses of pollen protein extracts from lily, timothy grass and tobacco with IgG antibodies directed against LLP-PG and against the timothy grass pollen allergen, Phl p 13, indicated that lily LLP-PG shares surface-exposed epitopes with pollen PGs from monocotyledonous and dicotyledonous plants. Enzyme-linked immunosorbent assay (ELISA) analyses and inhibition ELISA assays with patients' IgE demonstrated a very low IgE reactivity of lily rLLP-PG and a lack of cross-reactivity between rLLP-PG and the timothy grass pollen allergen, rPhl p 13. These data demonstrated that despite the significant sequence homology and the conserved surface-exposed epitopes LLP-PG represents a low-allergenic member of pollen PGs.

Allergens↗
PubMed1986

A study of oak-pollen production and phenology in northern California: prediction of annual variation in pollen counts based on geographic and meterologic factors.

To assess the characteristics of oak-pollen production and dispersal, 9 years of weekly volumetric air sampling, with modified swing-shield rotoslide pollen samplers, were obtained in San Francisco and San Jose, Calif. The Mediterranean climate of coastal California supports 9 million acres of oaks of nine different species. The major pollen contributors in the two sampling areas are coast live oak (Quercus agrifolia Neé) and valley oak (Quercus lobata neé). Sampling data indicate that grains may be wind transported at least 16 km (10 miles). A strong correlation exists between pollen capture and total rainfall a full year before pollen release. The correlation is statistically significant, based on a Spearman rank test. A positive regression line slope demonstrates that the greater the precipitation, the stronger the stimulus for pollen production. The median count can be predicted within a factor of two with high probability a full year before release. During most seasons, the peak pollen collection from coast live oak and valley oak occurs in early April. A second peak production period, in mid-May, represents the conglomerate of other oak-pollen types. However, there are major yearly differences in the relative amounts of pollen released during these two periods. Consequently, individual oak pollinosis may depend as much on variable production by the major species as on the total quantity of airborne oak pollen. These data will help clinicians predict and prepare for the intensity of the oak-pollen season and explain seasonal variations in clinical symptoms from year to year. The question of cross-reacting and specific allergens among oak species can be answered by RAST-inhibition studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗
PubMed1999

Pollen allergy in peach-allergic patients: sensitization and cross-reactivity to taxonomically unrelated pollens.

BACKGROUND: Fruit allergy has been attributed to cross-reactive IgE to pollens and has been associated with a particular pollen sensitization. OBJECTIVE: The aim of the study was to evaluate sensitization to several taxonomically unrelated pollens in peach- and pollen-allergic patients and to study cross-reactivity between them. METHODS: One hundred sixty-five patients were evaluated: 70 peach- allergic patients together with 95 pollen-allergic patients (control group). Pollen skin tests in duplicate were performed to 5 grasses, 8 trees, and 7 weeds. Cross-reactivity between peach and taxonomically diverse pollens was determined by radioallergosorbent inhibition and Western blot inhibition tests. Experiments were also carried out after preadsorption of the sera with purified natural profilin. RESULTS: The skin test results revealed that peach-allergic patients frequently reacted to most pollens-grasses, weeds, and trees-even when some of these are not found in our geographic area. There was a statistically significant increase in sensitization frequency to most trees and weeds, with a statistically higher occurrence of asthma (odds ratio 2.98, 95% confidence interval 1.46-6.09). Inhibition test results provided evidence that taxonomically unrelated grasses, weeds, and trees produced various and substantial degrees of inhibition in specific IgE to peach and that the peach extract elicited strong inhibitions to those pollens. Profilin was found to be a relevant cross-reactive antigen in these patients. CONCLUSION: The results of this study provide evidence that peach allergy is linked to sensitization to several taxonomically unrelated pollens. This is attributable to the ubiquitous nature of the IgE binding determinants-such as profilins-between peach and taxonomically unrelated pollens.

Adolescent↗
PubMed1996

IgE cross-reactivity between birch pollen, mugwort pollen and celery is due to at least three distinct cross-reacting allergens: immunoblot investigation of the birch-mugwort-celery syndrome.

BACKGROUND: Allergy to celery is often associated with sensitization to birch and/or mugwort pollen. OBJECTIVE AND METHODS: In a multi-centre study, sera from 23 patients suffering from type 1 allergy to celery and 15 patients with positive celery RAST but no clinical sensitization were compared. To examine whether cross-reactivity between celery and mugwort pollen includes cross-sensitization to birch pollen allergens, we determined cross-reacting structures in birch pollen, mugwort pollen and celery by means of immunoblotting. Inhibition studies were performed by preincubation of sera with extracts of birch pollen, mugwort pollen, and celery. RESULTS: We identified three groups of proteins--homologues of Bet v 1 and birch profilin (Bet v 2) as well as a group of proteins with a molecular range of 46 to 60 kD--displaying IgE-cross-reactivity, which were shared by birch pollen and celery. Two of these groups of allergens (profilin and the 46 to 60 kD proteins) were also present in mugwort pollen. In this paper we demonstrate that most cross-reacting allergens present in mugwort pollen and celery can also be detected in birch pollen extract. CONCLUSION: Therefore we propose, from a serological point of view, to extend the mugwort-celery syndrome to the birch-mugwort-celery syndrome.

Allergens↗
PubMed2004

LeSTIG1, an extracellular binding partner for the pollen receptor kinases LePRK1 and LePRK2, promotes pollen tube growth in vitro.

As pollen tubes grow through the pistil they are thought to perceive and respond to diverse signals. The tomato pollen-specific receptor kinases LePRK1 and LePRK2 might participate in signaling during pollen tube growth. We previously showed that the extracellular domain of LePRK2 interacts with a pollen protein, LAT52, before but not after pollen germination. To determine whether LePRK2 might have different binding partner(s) after pollen germination, we characterized two more proteins that, like LAT52, were identified in yeast two-hybrid screens using the extracellular domains of LePRK1 and LePRK2 as baits. We show that LeSHY, a leucine-rich repeat protein from pollen, and LeSTIG1, a small cysteine-rich protein from pistil, can bind the extracellular domains of both LePRK1 and LePRK2 in vitro. In vitro binding assays with the extracellular domain of LePRK2 suggested that LeSTIG1 could displace binding of LAT52, consistent with the idea that LePRK1 and LePRK2 might interact with different ligands at different stages of pollen tube growth. Exogenous LeSTIG1 promotes pollen tube growth in vitro. The interaction of these pollen kinases with LeSTIG1 supports the notion that LePRK1 and LePRK2 are involved in mediating pollen-pistil interactions.

Base Sequence↗
PubMed2003

Effects of simulated acid rain on the pollen germination and pollen tube growth of apple (Malus sylvestris Miller cv. Golden).

The pollens of apple flowers have been treated with simulated acid rain solutions in range of pHs 2.9 to 5.0 in order to determine the threshold proportion values that lead the observed symptoms of detriments of acid rain. Compared to controls (pH 6.5), pollen germination decreased by 41.75% at pH 3.3 and pollen tube elongation decreased by 24.3% at pH 3.4. Acid rain threshold proportion value was around pH 3.3 and 3.4 for apple pollen germination and pollen tube elongation, respectively. Furthermore, pollen tube elongation was determined to be more sensitive to acid rain than pollen germination. The pH values below 3.1 resulted in complete destruction of pollen tubes. Pollen germination entirely stopped at around pH 3.0. Finally, it has been shown that the acid rain has a blocking effect on pollen germination and pollen tube elongation in apple. The conclusion is that not only pH value but also the quantity of acid rain is important factor in germination. The results were found statistically significant through the LSD test at levels of p < 0.05 and p < 0.01.

Acid Rain↗
PubMedDate not supplied

Are there any links between Hop Japanese pollen and other weed pollens or food allergens on skin prick tests?

Recent investigations suggest that the importance of Hop Japanese pollen, which has been known as one of the major causative weed pollens, is increasing in this country. There have been few data dealing with the allergenic relationship between Hop J pollen and other food or inhalant allergens. Among 2909 patients who visited the Allergy Clinic of Ajou University Hospital, Suwon, Korea, 471 patients sensitized to Hop J, mugwort, or ragweed pollens on skin-prick test were enrolled. Positive rates to common inhalant or food allergens and their allergenic relationships with other pollens or food allergens were analyzed based upon skin-prick test results. The positive rates to sunflower, fat hen, nettle, grass (Bermuda, Orchard) and tree (alder, birch, and poplar) pollen were significantly higher in those sensitized to Hop J pollen than in those of negative responders (p < 0.05, respectively). No significant associations were noted with ragweed or mugwort pollen (p > 0.05, respectively). In regard to food-related allergens, an association was noted between Hop (Humulus lupulus) or celery allergens in those sensitized to Hop J pollen (p < 0.05, respectively). Hop J pollen may have possible links with celery, Hop, and sunflower pollens on skin-prick test. Further in vitro investigations will be needed to evaluate the possibility of cross-reacting components between them.

Allergens↗
PubMed2000

[Forecast of total pollen counts of sugi (Cryptomeria japonica) from the amount of male flower development and the revised total pollen counts].

We have successfully forecast the total pollen counts of sugi (Cryptomeria japonica) since 1996 by the amount of male flower development. The amount of male flower development was observed at 11 forests in the Tanba Mountains and 10 forests in the Chugoku Mountains depending on both in Hyogo Prefecture. The amount of male flower development on each tree was assigned to one of five classes by the number of male flowers per spring. After a large harvest of male flowers, the production of male flowers declined in the following years, especially at high altitudes. It was also followed by a decrease in the number of airborne pollen grains in the later pollen season. According to an analysis of weather conditions, total pollen counts were correlated with the high temperature between July 6 and 20 and the total pollen counts of the previous season. However, the amount of male flower development was the most significant indicator for forecasting total pollen counts. Decrease in total pollen counts due to abnormal weather during the pollen season was correlated with discrepancies in forest flowering time according to observations made in the Rokko Mountains. Increase in total pollen counts was connected by a development of the sugi forest areas. Twenty percent of mature sugi forests from 1992 which showed an annual increase were associated with an increase in total pollen counts. The accuracy of the forecast was improved by revising the total pollen counts for weather conditions during the dispersion stage, a decrease in the production of male flowers at high altitude, and an increase in the production of male flowers connected by a developing forest areas.

Air Pollutants↗
PubMed1999

[A relationship between birch pollen and meteorological factors during the past four years and pollen survey in Sapporo in 1997].

It is well known that grass pollinosis has been the most representative pollinosis in Hokkaido prefecture, Japan, However, it is also well known that birch (Japanese white birch, Betula platyphylla var. japonica) pollinosis is gradually increasing, which is marked especially in Sapporo and its neighborhood. We analyzed a relationship between the birch pollen count and meteorological factors statistically. Moreover, the principal airborne pollen counts in Sapporo in 1997 were assessed and compared with the previous pollen data. As a results of this study, it was showed a close relationship between the annual amounts of birch pollen and meterological factors of the year before, especially in May and June might be important. Moreover, there is a strong negative correlation between the birch pollen count and humidity, which seems to affect bringing up flower buds. As for the principal airborne pollen counts, some kinds of tree pollen, including birch pollen, were observed from the end of March, followed by grass (Gramineae) pollen in June and mugwort (Artemisia) pollen from the end of August, respectively. The annual amounts of grass pollen showed a decreasing trend.

Air Pollution↗
PubMed2005

[The effect of G protein regulator on pollen germination and [Ca2+]i variation in Pyrus serotina Rehd. pollen].

The effects of the cholera toxin (CTX) and pertussis toxin (PTX), which can activate and antagonize respectively the heterotrimeric G protein, on pollen germination, pollen tube growth and the dynamic of cytosolic free calcium concentration ([Ca(2+)]i) in pear pollen were investigated using Laser Confocal Scanning Microscope (LCSM). The results show that CTX could stimulate pollen germination and tube growth while PTX had the opposite effect. CTX and PTX had marked influence on the dynamic of pollen [Ca(2+)]i. The CTX treatment had no significant effect on the changes in pollen [Ca(2+)]i during pollen germination, but induced specific signaling of "calcium transient" in pollen. Treatment with PTX caused decline of pollen [Ca(2+)]i in the first 18 min after treatment. These data suggested that the regulation of pollen germination and tube growth in Pyrus serotina may involve in heterotrimeric G protein, which can stimulate specific change of pollen [Ca(2+)]i.

Calcium↗
PubMed1995

Confocal imaging and immunogold electron microscopy of changes in distribution of myosin during pollen hydration, germination and pollen tube growth in Nicotiana tabacum L.

Using anti-myosin antibodies, standard immunocytochemical techniques in conjunction with confocal scanning laser microscopy and colloidal gold immunoelectron microscopy we compare changes in the distribution patterns of myosin during the early stages of pollen hydration, germination, tube growth, and myosin associated with isolated vegetative nucleus and the generative cell in Nicotiana tabacum L. Furthermore, on the Western blots of pollen tube proteins, the antimyosin antibodies crossreact only with one polypeptide of approximately 174 kDa. Confocal immunofluorescence microscopy reveals that in hydrated pollen, myosin is discretely associated with the cytoplasmic organelles and numerous punctate structures present in the center of the pollen. Within 30 min following transfer of pollen into the germination medium, that is, with the onset of germination, the centrally located punctate structures are displaced, and we find accumulation of myosin-associated organelles towards one of the germinal apertures from which the pollen tube would emerge. Subsequently, after 45 min of germination with the emergence of germination structure, few punctate structures are detected in the vegetative cytoplasm while intense immunostain is detected just below the plasma membrane of the emerging pollen tube tip. In the older parts of both short and long pollen tubes after 90 to 120 min of pollen germination, few fluorescent structures were found in the pollen tubes, however, numerous punctate fluorescent spots were concentrated in the tip region over a distance of 2 to 3 microns below the plasma membrane of the tube tip. This is further substantiated by colloidal gold immunoelectron microscopy wherein clusters of gold particles are associated with vesicle-like structures in the tip region of the pollen tubes.(ABSTRACT TRUNCATED AT 250 WORDS)

Blotting, Western↗
PubMedDate not supplied

Pollen allergic disease: pollens and its major allergens.

Patients with grass pollen allergy, commonly called pollinosis, often present reactivity to pollen allergens from a number of grass species due to cross-reactivity of IgE antibodies to pollen proteins present in pollen grasses. In this context, Italian rye grass (Lolium multiflorum) pollen of the Poaceae family cultivated in Southern Brazil has been considered a major sensitizing agent in patients with pollinosis. In this region, Italian rye grass is capable of producing a great amount of pollen. In addition to L. multiflorum, other Poaceae grasses are naturally grown as weed in Southern Brazil, but with no clinical relevance. Pollen extracts derived from homologous or heterologous grasses are often used for both diagnosis and treatment of seasonal allergy. However, no standardized L. multiflorum pollen extract is commercially available in Brazil and mixed grass extracts are commonly used for diagnosis and immunotherapy of grass pollen allergy. Further studies are required to better characterize the cross-reactivity between L. multiflorum and other grass pollen allergens for improving the diagnosis and immunotherapy to L. multiflorum pollen allergy.

Allergens↗
PubMed1996

S RNase and Interspecific Pollen Rejection in the Genus Nicotiana: Multiple Pollen-Rejection Pathways Contribute to Unilateral Incompatibility between Self-Incompatible and Self-Compatible Species.

In self-incompatible (SI) plants, the S locus acts to prevent growth of self-pollen and thus promotes outcrossing within the species. Interspecific crosses between SI and self-compatible (SC) species often show unilateral incompatibility that follows the SI x SC rule: SI species reject pollen from SC species, but the reciprocal crosses are usually compatible. The general validity of the SI x SC rule suggests a link between SI and interspecific pollen rejection; however, this link has been questioned because of a number of exceptions to the rule. To clarify the role of the S locus in interspecific pollen rejection, we transformed several Nicotiana species and hybrids with genes encoding SA2 or SC10 RNase from SI N. alata. Compatibility phenotypes in the transgenic plants were tested using pollen from three SC species showing unilateral incompatibility with N. alata. S RNase was implicated in rejecting pollen from all three species. Rejection of N. plumbaginifolia pollen was similar to S allele-specific pollen rejection, showing a requirement for both S RNase and other genetic factors from N. alata. In contrast, S RNase-dependent rejection of N. glutinosa and N. tabacum pollen proceeded without these additional factors. N. alata also rejects pollen from the latter two species through an S RNase-independent mechanism. Our results implicate the S locus in all three systems, but it is clear that multiple mechanisms contribute to interspecific pollen rejection.

Journal Article↗