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Background and aims: Paspalum lilloi (Poaceae) is a diploid species, endemic of Iguazú Waterfalls and nearby areas. The reproductive biology and current geographical distribution of this species are poorly known. The aims of this work were to determine the genetic system and to delimit the endemism area and conservation status of the species. M&M: The genetic system was determined by cytoembryological analysis of ovules, viability and in vivo germination of pollen grains, pollen-pistils compatibility, fertility and flow cytometry of single seeds. Herbarium specimens and our collection sites delimited the geographical distribution. Results: Meiotic embryo sacs of Polygonum type were observed in all analyzed ovules. No evidence of apomixis was detected. The mean pollen viability and in vivo pollen germination was 95.2% and 41.8%, respectively. The pollen tube growth in the selfed stigmas was 59.2 ± 6.39 µm / 3h. Seed set in self-pollination was 93.6 % and decreased to 52.7 % when there was heterospecific pollen available. Seeds analyzed by flow cytometric seed screen showed an embryo: endosperm ratio 2:3 indicated a sexual origin. Paspalum lilloi is a reophile and rupicolous species, specialized in fast-moving waters of waterfalls and it is a critically endangered endemism of Iguazu Waterfalls, in South America. Conclusions: P. lilloi is sexual, self-compatible and self-fertile species. Has a highly specialized habitat, which conservation will be a key step to avoid its extinction. [ABSTRACT FROM AUTHOR]

Background and aims: Cultivars of Canna resulted of intensive hybridization on five parental species: C. flaccida Salsb., C. glauca L., C. indica L., C. iridiflora Ruiz et Pav. and C. warscewiczii A. Dietr. Here we study for the first time the palynological morphology and pollen viability of three hybrids belonging to the nothospecies C. x generalis and three parental species, C.glauca, C. indica and C. warscewiczii, that grow in Argentina. The objective of this work is to contribute with information about hybridization and artificial evolution of the genus Canna through a study of palynological morphology and pollen viability. M&M: Pollen grains of live flowers were observed with an optical microscopy following Wodehouse technique. As Canna pollen grains do not resist Erdtman acetolysis, the observation of sporoderm and spines was performed with a scanning electronic microscope, whereas pollen viability was studied through MTT technique, (Rodriguez-Riano & Dafni 2000). Results: In wild species the shape and size of pollen grains are regular as well as the size, morphology, distribution, and density of spines. In the hybrids the mentioned traits result irregular and spines density is 2-3 times higher. Conclusions: Pollen viability results were correlated with the presence and absence of seeds. [ABSTRACT FROM AUTHOR]

Phyllanthus ×pallidus, of parentals P. discolor and P. comptus, is the only hybrid within the genus Phyllanthus registered for Cuba. Prior studies in the hybrid were not conclusive in the macroscopic morphology and the pollen viability, in addition to the fact that other researchers assumed P. orbicularis and P. discolor as the parents of the hybrid. The present study aimed to compare the morphological characters of the shrub species of Phyllanthus in the Sierra de Cajálbana, to corroborate the origin of P. ×pallidus and its possible parents. Collections were made in Cajálbana of P. discolor and P. ×pallidus and the data previously published in Cajálbana of P. orbicularis were taken. In the case of P. comptus, only herbarium material was used since it could not be found in the field at sampling time. Qualitative and quantitative comparisons between the different taxa in terms of vegetative and reproductive morphological characters were made. The pollen viability in the different taxa was analyzed. Morphological anomalies were found in the flowers of the hybrid and the pollen in every analyzed taxa presented a high percentage of viability. The results obtained proved that P. ×pallidus is vegetatively similar to P. orbicularis and reproductively to P. discolor, which could confirm that P. ×pallidus is a hybrid and that its most probable parents are P. orbicularis and P. discolor. [ABSTRACT FROM AUTHOR]

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Knowledge about pollen biology is fundamental for the planning of controlled crosses in programs of conservation and genetic improvement of plant species. The objectives of this research were to determine the ideal medium for in vitro germination of pollen and to evaluate the effect of temperature and drying on the viability of stored pollen from Ochroma pyramidale. Pollen was obtained from flowers collected before anthesis. The appropriate culture medium for in vitro germination of pollen was determined by testing modifications of the medium proposed by Brewbaker and Kwack. Pollen drying was performed during different times (60, 120, 180 and 240 minutes) at 29 °C and 45 % relative humidity. These samples were stored under temperatures of 5, -20 and -196 °C, and evaluated for 45 days. The ideal medium for pollen germination was composed of 10 % sucrose, 30 mg L-1 boric acid, 430 mg L-1 calcium nitrate. The initial viability calculated by in vitro germination was high, which indicates that the individuals evaluated can be used as pollen donors in the controlled crossing plans. Humidity below 5 % allowed keeping the pollen stored, independently of the storage temperature during the 45 days of the test, without significant decrease in their viability and germination rate. However, pollen viability decreased rapidly when it was stored with high moisture content, regardless of storage temperatures. [ABSTRACT FROM AUTHOR]

Copyright of Lilloa is the property of Fundacion Miguel Lillo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of the present study was to characterize karyologically species of Passiflora L. from Félix Pérez Cardozo District, Guairá, Paraguay. The chromosome numbers in meiosis 2n = 9II for P. alata Curtis and P. caerulea L. are reported for the first time. Chromosome number for P. edulis Sims (2n = 9II) is also confirmed. Meiotic behaviour in all studied species was normal with regular chromosome segregation. The most frequent chromosome associations were bivalents at diakinesis and metaphase I. Few meiotic irregularities were observed, such as lagging chromosomes and asynchronous phases of meiosis II, however, pollen viability was high, between 78.83% and 98.6%. The obtained results confirms x = 9 as the basic chromosome number for subgenus Passiflora. The present study is a relevant contribution to the knowledge on the cytogenetics of species of Passiflora subg Passiflora from Paraguay. [ABSTRACT FROM AUTHOR]

Copyright of Boletín Científico Centro de Museos de Historia Natural is the property of Universidad de Caldas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Agro Productividad is the property of Colegio de Postgraduados and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Facultad de Ciencias Basicas is the property of Revista Facultad de Ciencias Basicas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To evaluate possible developmental alterations in male gametes in the progeny of a sunflower inter-subspecific cross, pollen viability was studied in the cultivated line AN-3, the wild subspecies Helianthus annuus ssp. texanus, and in the hybrid from the cross CMS-AN-3 x H. annuus ssp. texanus. Among the hybrid plants, 95% of the individuals showed male fertility, thus indicating that the target wild populations contain male-sterility restoration alleles. Pollen viability did not show significant differences between the hybrid (91.5%), the cultivated (94.6%) and wild parents (95.2%). Results suggest that pollen viability is a trait maintained at high levels in wild and cultivated sunflower populations, and that there is no indication that sunflower domestication had an effect on this character. Regarding the use of wild material to improve the cultivated sunflower, pollen viability is not a barrier to use local populations (southeast of Coahuila) of H. annuus ssp. texanus to introduce wild genetic material to elite varieties. [ABSTRACT FROM AUTHOR]