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PubMed2006

Practice parameters for sublingual immunotherapy.

The efficacy and safety of sublingual immunotherapy (SLIT) are currently supported by clinical trials, meta-analysis and post-marketing surveys. Practice parameters for clinical use of SLIT are proposed here by a panel of Italian specialists, with reference to evidence based criteria. Indications to SLIT include allergic rhinoconjunctivitis, asthma, and isolated conjunctivitis (strength of recommendation: grade A). As to severity of the disease, SLIT is indicated in moderate/severe intermittent rhinitis, persistent rhinitis and mild to moderate asthma (grade D). SLIT may be safely prescribed also in children aged three to five years (grade B), and its use in subjects aged more than 60 years is not prevented when the indications and contraindication are ascertained (grade D). The choice of the allergen to be employed for SLIT should be made in accordance with the combination of clinical history and results of skin prick tests (grade D). Polysensitisation, i.e. the occurrence of multiple positive response does not exclude SLIT, which may be done with the clinically most important allergens (grade D). As to practical administration, co-seasonal, pre co-seasonal, and continuous schedules are available, being the latter recommended for perennial allergens or for pollens with particularly prolonged pollination, such as Parietaria (grade D). For pollens with relatively short pollination, such as grasses and trees (cypress, birch, alder, hazelnut, olive) the pre co-seasonal and perennial schedules are preferred (grade C). The build-up phases suggested by manufacturers can be safely used (grade A), but they can be modified according to the patient's tolerance (grade C). A duration of SLIT of 3-5 years is recommended to ensure a long-lasting clinical effect after the treatment has been terminated (grade C).

Administration, Sublingual↗
PubMed1999

Fruit set in Styrax obassia (Styracaceae): the effect of light availability, display size, and local floral density.

Maternal reproductive success was examined in Styrax obassia (Styracaceae), a bumble-bee pollinated mass-flowering tree in a cool-temperate deciduous forest in northern Japan. The effects of flower number on the success of individual flowers at three levels (inflorescence, individual, and population) were considered. During 1995 and 1996, variations in size, light availability to branches, floral display size, and fruit set were monitored in 37 out of 211 individual S. obassia trees in a 4-ha forest plot. In addition, the locations of the 211 trees in this plot were mapped and the number of inflorescences in each tree was counted. A multiple regression analysis showed that flower number per inflorescence and inflorescence number per individual had negative effects on fruit set, and inflorescence number of aggregated clumps of flowering trees, tree size, and light resource had positive effects on fruit set although significant level were marginal. It is concluded that pollinator attraction may occur not at the individual tree level, but at the level of a clump of flowering trees. It is also suggested that geitonogamy increased with inflorescence number of tree and inflorescence size and that resource limitation was related to the light condition and variation of tree size.

Journal Article↗
PubMed1999

Reproductive biology of Lactoris fernandeziana (Lactoridaceae).

Lactoris fernandeziana, monotypic in its family, is endemic to the cloud forests of Robinson Crusoe Island. Although there has been considerable study of the relationships of Lactoris, as a rare species and as a putative primitive paleoherb, little is known of its reproductive biology. Knowledge of the latter is essential for effective conservation programs. The species is gynomonoecious. The overall proportion of flowers is ∼1 female:1 hermaphrodite. The inconspicuous semipendulous green flowers, usually in mixed-gender inflorescences, do not produce rewards. Hermaphrodite flowers are herkogamous and protogynous. Pollen grains are shed from the extrorse anthers in permanent dry tetrads. There is a mean of 12879 tetrads per hermaphrodite flower. Both flower types bear an average of ∼18 ovules. The P/O (pollen/ovule) ratios imply facultative or obligate xenogamy, but hand pollinations show that Lactoris is self-compatible. No floral visitors were ever observed, but stigmata of open-pollinated flowers bore tetrads, and 64% of such styles had pollen tubes. Flowers enclosed in large mesh (1 mm) bags bore similar numbers of tetrads and pollen tubes. Thus, we conclude that Lactoris is anemophilous, a syndrome perhaps reflected by the P/O ratio. Low genetic diversity (isozymes and DNA) supports selfing and implies limited distance wind pollen dispersal. The small size of the island, the ± 1000 extant Lactoris plants, coupled with anemophily, self-compatibility, and pendant flower position, have yielded a geitonogamous system with high seed set and low genetic diversity. If inbreeding depression is expressed, it is in seed germination and seedling vigor, for Lactoris is very difficult to cultivate. For this species, effective conservation practices need to focus on habitat preservation and promotion of outcrossing.

Journal Article↗
PubMed1999

Why be a honeyless honey mesquite? Reproduction and mating system of nectarful and nectarless individuals.

Populations of Prosopis glandulosa var. torreyana in the Chihuahuan desert have a fixed dimorphic system of nectar production in which half the individuals produce nectar (are nectarful) and the other half are nectarless. We analyzed the impact of nectar production on different estimates of fitness, comparing nectarful against nectarless individuals in size, mating system, seed traits, and fruit set in a 1-ha scrubland. Of the reproductive individuals (358), 46% were nectarful and 54% were nectarless. Neither tree size nor flowering phenology differed between nectar morphs. Fixation indices (F) for both progeny (F = -0.2) and adults (F = -0.45) were negative, and high heterozygosities were found in adults and progeny (H = 0.45). No differences were found between nectar morphs for F, H, and single (t(s) = 1.1) and multilocus (t(m) = 1.03) outcrossing rates. Controlled pollinations showed differences between selfing and control treatments with no differences between nectar morphs. Nectarless individuals produced significantly more pollen grains than did nectar producers, but all other measured floral traits showed no differences. Nectarful trees were visited by pollinators 21 times more often and had a significantly higher overall fruit set than did nectarless trees. No differences between nectar morphs in seed mass or in percentage seed germination were found, but heavier seeds tended to have higher heterozygosities. Both morphs had similar success as females, but nectarless trees had ∼7% higher male function. We discuss three possible scenarios for the evolution of the fixed dimorphism in nectar production, two involving unstable phases (substitution of one morph by the other, and evolution towards dioecy) and one stable scenario (maintenance of the dimorphic system).

Journal Article↗
PubMed1999

Genetic structure of Helianthus occidentalis (Asteraceae) in a preserve withfragmented habitat.

We examined the spatial genetic structure of Helianthus occidentalis Riddell ssp. occidentalis Riddell (western sunflower) to determine whether this species is highly clonal and whether the distance between prairie patches influences genetic differentiation. In the Edge of Appalachia Preserve System, Ohio, this species is restricted to prairie patches that have a clumped distribution in the forest matrix. Data from this insect-pollinated forb with gravity-dispersed seed were compared to data from the same patches for Asclepias verticillata, an insect-pollinated species with wind-dispersed seed. Allozyme electrophoresis was used to collect genetic data from H. occidentalis samples from eight patches in four regions. Genetic data from three polymorphic loci indicted that this species is not highly clonal. Genetic differentiation was greater among patches within a region than among regions, suggesting that gene flow among patches is more limited in H. occidentalis than in A. verticillata. Founder effect may also have contributed to observed genetic differences among patches as some of these populations may have re-established after release from human use. As habitat fragmentation is increasing in the preserve, it is also likely that genetic differentiation may be increasing. Therefore, monitoring of genetic structure is necessary to further assess the effect of fragmentation.

Journal Article↗
PubMed1999

Plant reproductive phenology over four years including an episode of general flowering in a lowland dipterocarp forest,Sarawak, Malaysia.

The first systematic observation of a general flowering, a phenomenon unique to lowland mixed-dipterocarp forests in Southeast Asia, is presented. During general flowering, which occurs at irregular intervals of 3-10 yr, nearly all dipterocarp species together with species of other families come heavily into flower. We monitored reproductive phenology of 576 individual plants representing 305 species in 56 families in Sarawak, Malaysia. Observations continued for 53 mo from August 1992 and covered one episode of a general flowering cycle. Among 527 effective reproductive events during 43 mo, 57% were concentrated in the general flowering period (GFP) of 10 mo in 1996. We classified 257 species into flowering types based on timing and frequency of flowering. The most abundant type was "general flowering" (35%), which flowered only during GFP. The others were "supra-annual" (19%), "annual" (13%), and "sub-annual" (5%) types. General flowering type and temporal aggregation in reproductive events were commonly found among species in various categories of taxonomic groups, life forms, pollination systems, and fruit types. Possible causes for general flowering, such as promotion of pollination brought about by interspecific synchronization and paucity of climatic cues suitable for flowering trigger, are proposed, in addition to the predator satiation hypothesis of Janzen (1974).

Journal Article↗
PubMed1999

[A study of aggravation of atopic dermatitis during Japanese cedar pollen season--correlation with grades of dermatitis on face and Cry j 1 specific IgE].

We studied influence of Japanese cedar pollen (Jcp) on aggravation of atopic dermatitis (AD) during the pollination season. 48.5% of 97 patients with atopic dermatitis showed aggravation of dermatitis during the pollination season and 85% of them had Japanese cedar pollinosis, whereas only 44% of AD patients without the aggravation had the pollinosis. There was no difference of grades of dermatitis on face between the groups with or without the aggravation. Furthermore, we measured specific IgE to Jcp and Cry j 1, a major allergen of Jcp, by ELISA in the sera from the 54 patients with AD. The levels of specific IgE antibodies to both allergens in the group with the pollinosis were significantly higher than in the group without the pollinosis. However, significant difference of those was not recognized between the groups with or without the aggravation of AD. Therefore, our study has suggested that Japanese cedar pollen is likely to be one of causes of seasonal aggravation of AD in individuals sensitized to the pollen, and some other factors, e.g. Jcp-specific T cells, might play an important roll in addition to the Jcp-specific IgE.

Adolescent↗
PubMed1999

A clinical study of airborne allergens in the United Arab Emirates.

BACKGROUND: In the past 25 years the United Arab Emirates (UAE) have experienced a socioeconomic boom. The once nomadic Bedouin population of Al Ain, in the emirate of Abu Dhabi, now lives in modern air-conditioned accommodation, and huge desalination plants have allowed afforestation and farming. OBJECTIVE: To evidence responsible airborne allergens in an UAE population. PATIENTS AND METHODS: 263 UAE Nationals who attended Tawam Hospital (Al Ain, UAE) with a respiratory disease suspected of being of allergic origin, were submitted to SPT and RAST. The choice of pollinic allergens was made in accordance with the local flora and market availability. All patients were SPTed with at least the same battery of 15 pollinic and indoor allergens. Most patients were submitted to at least 4 RAST, viz Cynodon dactylon, Salsola kali, Prosopis juliflora and Dermatophagoides pteronyssinus. RESULTS: 71.8% patients were positive for at least one allergen. Pollen accounted for 61.6% of positive patients, with 45.2% positive to chenopodiaceae, 33% to gramineae and 23.5% to P. juliflora. Indoor allergens were positive in 30.4% of patients with 17.9% positive to D. pteronyssinus and D. farinae, 11% to Blatella germanica, 8.3% to Cat fur, 4.9% to Goat hair, 0.7% to Rat hair and Mouse hair and 1.5% to Candida albicans. CONCLUSION: Pollen was the prominent allergen. There is room, however, for further epidemiological studies possibly with new extracts and RAST specifically designed after the species of the Gulf region.

Air Pollutants↗
PubMed1999

Development of simple sequence repeat markers in rye (Secale cereale L.).

Simple sequence repeats (SSRs), also referred to as microsatellites, represent a PCR-based marker system that has been described in mammalian and plant genomes in recent years. In self-pollinating crop plants they have been shown to be superior to other DNA markers with respect to their level of polymorphism. The technical advantages compared with RFLP markers should also facilitate marker analysis in outcrossing crops like rye. In order to determine the usefulness of SSR markers in rye genetics and breeding, several genomic libraries were screened for (CT/GA)n and (GT/CA)n dinucleotide repeats. It was estimated that these motifs occur at a frequency of one per 268-519 kb. Seventy four out of 182 positive clones were sequenced, and the majority (56.8%) revealed perfect repeats, predominantly of the type (GT/CA)n (61.9%). Fifty seven primer pairs were designed and 27 (47.4%) resulted in specific SSR markers, of which 20 were genetically mapped or assigned to chromosomes or chromosome arms, respectively. The level of polymorphism of four SSR and three RFLP markers was assessed in two open-pollinated rye cultivars. On average, the SSR markers showed larger values of expected heterozygosity (0.62 vs. 0.43) and allele number (5.9 vs. 3.4) than RFLP markers in both cultivars.

Base Sequence↗
PubMed1999

Trade-offs between flower number and investment to a flower in selfing and outcrossing varieties of Impatiens hypophylla (Balsaminaceae).

Floral resource allocation was compared on a whole-plant basis between two varieties of Impatiens hypophylla that differ in flower size. There were significant negative correlations between flower number and investments to a flower at both the within-population and between-variety levels. In individual flowers, var. hypophylla with larger flowers invested significantly more resources to male and pollinator-attractive functions, whereas investments to female function did not differ between the varieties. In experimental populations placed in the field, pollinators preferred the larger flowers of var. hypophylla even within the same habitat of var. microhypophylla, which has smaller flowers. There was a significant lack of observed heterozygosity only in var. microhypophylla. Thus, the outcrossing variety had more attractive but fewer flowers, while the selfing variety had less attractive but more abundant flowers.

Journal Article↗
PubMed2000

Comparative pollen morphology and ultrastructure of the Callitrichaceae.

The Callitrichaceae are an aquatic family of dicots that include the single, geographically cosmopolitan genus Callitriche. Callitriche contains 40-50 terrestrial, amphibious, and obligately submersed species, and it is the only known genus in the plant kingdom with co-occurring aerial and hydrophilous pollination syndromes. Pollen morphology and ultrastructure were described for 13 Callitriche species using scanning electron and transmission electron microscopy. Representative taxa of each growth form were examined; these included three terrestrial species (C. deflexa, C. peploides, and C. nuttallii), nine amphibious species (C. brutia, C. cophocarpa, C. cophocarpa-stagnalis hybrid, C. cribrosa, C. hamulata, C. heterophylla var. heterophylla, C. lusitanica, C. marginata, and C. trochlearis), and one obligately submersed species (C. truncata). Of the amphibious taxa, C. heterophylla var. heterophylla and C. trochlearis had internal geitonogamy, a type of internal self-fertilization. Pollen from all taxa was spheroidal, small, intectate, and lacked well-defined apertures. Taxa primarily differed with respect to exine thickness, surface ornamentation, and the presence or absence of aperture-like regions. The pollen of terrestrial species, as well as that of C. marginata, had well-developed exines with thick sculptured and basal layers. In general, amphibious taxa produced pollen with distinct, but thinner, exines than that of terrestrial taxa. Pollen of the amphibious taxa with internal geitonogamy had a thicker basal layer than species without internal geitonogamy, whereas the overall exine was reduced in C. hamulata and absent in C. brutia and C. lusitanica. Pollen of the obligately submersed C. truncata also lacked an exine. These palynological data were correlated with growth habits and related pollination biologies, as well as with phylogenetic interpretations of Callitrichaceae. Exine reduction or loss has evolved at least twice in the family, and it is associated with aneuploid reduction in chromosome number.

Journal Article↗
PubMed2000

The absence of cryptic self-incompatibility in Clarkia unguiculata (Onagraceae).

Many species exhibit reduced siring success of self-relative to outcross-pollen donors. This can be attributed either to postfertilization abortion of selfed ovules or to cryptic self-incompatibility (CSI). CSI is a form of self-incompatibility whereby the advantage to outcross pollen is expressed only following pollinations where there is gametophytic competition between self and outcross pollen. Under the definition of CSI, this differential success is due to the superior prefertilization performance (pollen germination rate and pollen tube growth rate) of outcross pollen relative to self pollen. Although CSI has been demonstrated in several plant species, no studies have assessed among-population variation in the expression of CSI. We conducted a greenhouse study on Clarkia unguiculata (an annual species with a mixed-mating system) to detect CSI, and we compare our observations to previous reports of CSI in C. gracilis and another population of C. unguiculata. In contrast to these previous studies of CSI in Clarkia, we used genetic rather than phenotypic markers to measure the relative performance of selfed vs. outcross pollen. In this study, we measured the intensity of CSI in C. unguiculata from a large population in southern California and we determined whether the magnitude of pollen competition (manipulated by controlling the number of pollen grains deposited on a stigma) influenced the outcome of competition between self and outcross pollen. In contrast to previous investigations of Clarkia, we found no evidence for CSI. The mean number of seeds sired per fruit did not differ between self and outcross pollen following either single-donor or mixed pollinations. In addition, the relative success of selfed vs. outcross pollen was independent of the magnitude of pollen competition. These results suggest that: (1) one of the few nonheterostylous species previously thought to be cryptically self-incompatible is completely self-compatible (at least in the population studied here) or (2) phenotypic markers may be problematic for the detection of CSI.

Journal Article↗
PubMed2000

Phylogenetic relationships of functionally dioecious FICUS (Moraceae) based on ribosomal DNA sequences and morphology.

Figs (Ficus, Moraceae) are either monoecious or gynodioecious depending on the arrangement of unisexual florets within the specialized inflorescence or syconium. The gynodioecious species are functionally dioecious due to the impact of pollinating fig wasps (Hymenoptera: Agaonidae) on the maturation of fig seeds. The evolutionary relationships of functionally dioecious figs (Ficus subg. Ficus) were examined through phylogenetic analyses based on the internal transcribed spacer (ITS) region of nuclear ribosomal DNA and morphology. Forty-six species representing each monoecious subgenus and each section of functionally dioecious subg. Ficus were included in parsimony analyses based on 180 molecular characters and 61 morphological characters that were potentially informative. Separate and combined analyses of molecular and morphological data sets suggested that functionally dioecious figs are not monophyletic and that monoecious subg. Sycomorus is derived within a dioecious clade. The combined analysis indicated one or two origins of functional dioecy in the genus and at least two reversals to monoecy within a functionally dioecious lineage. The exclusion of breeding system and related characters from the analysis also indicated two shifts from monoecy to functional dioecy and two reversals. The associations of pollinating fig wasps were congruent with host fig phylogeny and further supported a revised classification of Ficus.

Journal Article↗
PubMed2000

The evolution of staminodes in angiosperms: patterns of stamen reduction, loss, and functional re-invention.

Stamens that have lost their primary function of pollen production, or staminodes, occur uncommonly within angiosperms, but frequently fulfill important secondary floral functions. The phylogenetic distribution of staminodes suggests that they typically arise during evolutionary reduction of the androecium. Differences in the genetic control and patterns of stamen loss between actinomorphic and zygomorphic flowers shape staminode development. In clades with actinomorphic flowers, staminodes generally replace an entire stamen whorl and staminode loss seems irreversible. In contrast, in clades with zygomorphic flowers staminodes evolve from a subset of the stamens in a whorl and staminodes can reappear in a lineage after being lost (e.g., Cheloneae, Scrophulariaceae). If staminodes do not adopt new functions during androecium reduction they are lost quickly, so that nonfunctional staminodes appear only in recently derived taxa. Alternatively, when staminodes assume new floral roles, either directly or indirectly after a nonfunctional period, they can become integral floral components which perpetuate within clades (e.g., Orchidaceae). Indirect evolution of staminode function allows greater flexibility of function by allowing staminodes to take over roles not performed by stamens, such as involvement in mechanisms to prevent self-pollination and mechanisms of explosive pollination. Multifunctional staminodes characterize lineages with universal or widespread staminodes.

Journal Article↗
PubMed2000

Effect of pollen load size and source (self, outcross) on seed and fruit production in highbush blueberry cv. 'Bluecrop' (VACCINIUM CORYMBOSUM; Ericaceae).

Reproductive fitness of a plant is ultimately determined by both number and quality of seed offspring. This is determined by sexual selection of pollen microspores and ovules during pollination and fertilization. These processes may include pollen competition and seed abortion, which reduce the number of microspores and ovules available for final seed production. Thus, even an excess of pollen microspores to ovules does not result in fertile seeds equal to ovule number. We investigated pollen requirements of highbush blueberry (Vaccinium corymbosum cultivar 'Bluecrop') for maximal seed production and how fertile seed number translates into fruit quality, since fruit quality would ultimately determine the dispersal of its offspring. We demonstrate that individual blueberry flowers with a mean of 106 ovules reach their maximum fruit set and mass and minimum time to ripen when 125 outcross pollen tetrads pollinate a flower, compared to 10 or 25. Three hundred tetrads resulted in the increase of fertile seeds, but did not result in a further increase of fruit mass or fruit set, or decrease in time to ripen. We also examined the effect of pure and mixed loads of self and outcross pollen (25 and 125 tetrads), and found no differences in fertile seed number, fruit mass, or percentage fruit set when pollen loads were either 25 self or outcross pollen tetrads, although number of days to ripen was significantly shorter by 8 d with 25 outcross tetrads. When the pollen load of 125 tetrads consisted of self or a 50:50 mixture of self and outcross pollen, fruit mass, days to ripen, and percentage fruit set were not different from loads of 125 outcross pollen. In addition, a pollen load of 25 outcross tetrads resulted in fertile seed number and fruit quality in between that of 25 self, and 125 self, 125 mixed, or 125 outcross tetrads. Large, small, and flat seed types were identified, and only large seeds (length = 1.7 mm) were fertile. These results improve our understanding of pollen load size and source requirements of a crop plant and the limits to pollen transfer when translated to fruit growth.

Journal Article↗
PubMed2000

Unfertilized ovules of Epilobium obcordatum (Onagraceae) continue to grow in developing fruits.

To determine whether unfertilized ovules continue to grow when in an ovary containing fertilized ovules, we measured ovule lengths in developing fruits of Epilobium obcordatum that were harvested 4, 5, 8, and 10 d post pollination. We found that unfertilized ovules that were in the presence of fertilized ovules continued to grow and that there was a broad range of overlap in their sizes at all sampling times. This effect was found for two types of unfertilized ovules that occur throughout the length of the ovary: normal, unfertilized ovules, apparently bypassed by pollen tubes; and sterile ovules lacking an embryo sac. In addition, there is a position effect within developing fruits. Both fertilized and unfertilized ovules are larger at the stylar end. In six samples resulting from pollination with a single pollen tetrad, a total of 18 embryos were found, and the effect on unfertilized ovules, greatest at the stylar end, diminished with distance from the ovules with embryos. Our results are consistent with the interpretation that diffusible hormones produced by developing seeds cause nearby unfertilized ovules to grow. We conclude that caution is necessary when attempting to infer ovule fertilization histories from the appearances of ovules in developing and mature fruits. What are often inferred to be aborted seeds, in many cases, may not be seeds at all. They may be enlarged, unfertilized ovules.

Journal Article↗
PubMed2000

Preliminary results on embryo rescue for circumventing hybridization barriers in Asparagus.

Garden asparagus, Asparagus officinalis, is reproductively isolated from a related ornamental species with potential breeding value, Asparagus densiflorus cv. Sprengeri, by pre- and post-zygotic barriers. The latter barrier operates at the endosperm level five days after pollination in A. officinalis x A. densiflorus crosses. To try to circumvent this barrier, in vitro embryo rescue using ovule and ovary cultures was tested. Controlled interspecific crosses were made and 2,032 ovules and 826 ovaries were cultured three days after pollination under various culture media and incubation conditions. Ovaries cultured for 60 days became red (similar to mature fruits), but seed formation was incomplete. Transfer of ovules to other media was necessary to promote embryo development. The interspecific embryos increased their length from 35 microns at the initiation of culture to 1,900 microns after 120 days of culture, but seedlings were not obtained. Histological studies revealed differentiation of protoderm only. The possible causes of the failure of the embryos to complete differentiation and morphogenesis are discussed.

2,4-Dichlorophenoxyacetic Acid↗
PubMedDate not supplied

[Creation of maize lines inducing maternal haploids with high frequency].

The new inducers of maternal haploids have been created. The results on their inducing capacity in crossing with MK01u and A619 lines and MK01u x A619 hybrid are presented. Pollination with pollen of the new inducers allowed to obtain in average 6.5% of haploids among the three maternal genotypes. The ZMS and KMS initial lines induced 2.3% and 2.0% of haploids respectively. The frequency of haploids was studied in different parts of ears. It was found that in the higher part of an ear where the egg cells are the youngest during flowering the frequency of haploids was almost three times higher than in the lower part of an ear and more than twice higher than in the middle part of an ear. It was assumed that early pollination may increase frequency of obtaining haploids.

Crosses, Genetic↗