Oblong Seeds Research Articles

Flora of Espírito Santo: tribe Microlicieae (Melastomataceae)

Abstract Microlicieae is one of the most diverse tribes in Melastomataceae, comprising three genera: Microlicia (including the former Chaetostoma, Lavoisiera, Stenodon, and Trembleya), Poteranthera, and Rhynchanthera. It is characterized by anthers with a prolonged pedoconnective, capsular fruits, and reniform, oblong seeds with a foveolate testa. This study presents a taxonomic treatment for the species of Microlicieae in the state of Espírito Santo. A total of ten species were registered in two genera, Microlicia (9 spp.) and Rhynchanthera (1 sp.). Of these, three are new species of Microlicia: M. caparaoensis is endemic to the Caparaó National Park; M. capixaba and M. misteriosa are endemic to a single inselberg, the “Alto Misterioso”, in São Roque do Canaã. A fourth species was kept as Microlicia sp., since further studies will be necessary to confirm its identity. We also provide an identification key, morphological descriptions, distribution data, and comments for all species.

Inferring trait‐based mechanisms and variance consequences of abiotic secondary dispersal from the spatio‐temporal distribution of a desert soil seed bank

AbstractQuestionsQuantifying the combined effects of seed traits, microsite types, and abiotic dispersal agents on the mean and variance of seed bank density and composition will help understand vegetation dynamics in deserts. In a site with NE slope and mainly southerly winds, we asked whether large and oblong seeds were more likely to be transported and deposited in water obstructions and underneath the northern part of shrub understories. We also asked whether seed standing crop was less variable in water obstructions than in other microsites less affected by seed deposition.LocationA sand field in San Juan province, Argentina.MethodsWe sampled the soil seed banks of four microsite types: water obstructions where debris/litter accumulates, southern and northern shrub understories, and open spaces among shrubs. Sampling was carried out in 11 plots and replicated at six moments between 2010 and 2012.ResultsDebris microsites showed the highest levels of seed density, species richness and standing crop; seed density and standing crop were also least variable in these microsites. Debris microsites also contained high seed abundance of stress‐intolerant, shrub‐dependent species. Seed density, species richness, seed standing crop, and the proportions of both large and oblong seeds were all higher in northern than in southern understories. The relationship between seed mass and the proportion of seeds that were apparently retained (i.e., not washed away and deposited in water obstructions) was more strongly negative in southern than in northern understories.ConclusionsNorthern and southern understories appeared to act as water run‐on (i.e., seed recipients) and run‐off zones (i.e., seed donors), respectively. Seed accumulation under the shelter provided by shrubs may promote seed predation in these microsites. Abiotic dispersal would therefore contribute to the maintenance of vegetation patches when seed arrival underneath shrub canopies saturates granivore consumption.

مقایسه برخی ازخصوصیات فیزیکی و شیمیایی سه ژنوتیپ زرشک دانه‌دار بومی استان سمنان

کسب اطلاعات در مورد گیاهان بومی بعنوان منابع غذایی عملگر (فراسودمند) رو به افزایش است. یکی از این گیاهان، گونه‌های وحشی زرشک(Berberis. spp.) می‌باشد که بررسی خصوصیات فیزیکی و شیمیایی آنها می‌تواند زمینه کاربردشان را در صنایع غذایی و دارویی فراهم کند. لذا در این پژوهش بمنظور معرفی بیشتر این گیاه ارزشمند بومی، سه ژنوتیپ موجود در باغ کلکسیون زرشک پژوهشکده علوم و صنایع غذایی درسال 1390جمع‌آوری و برخی از خواص فیزیکی و شیمیایی آنها مورد بررسی قرار گرفت. نتایج حاکی از آن بود که بین خصوصیات فیزیکی بررسی شده فقط در طول میوه سه ژنوتیپ اختلاف‌ آماری معنی‌داری در سطح 5 درصدوجود داشت. هر سه ژنوتیپ حاوی میزان بالای چربی، پروتئین، کربوهیدرات و خاکستر بودند. ژنوتیپ نوشین دارای بالاترین قند احیاکننده (222/0±03/8) و در نتیجه دارای مزه شیرین‌تری نسبت به دو ژنوتیپ دیگر بود. هر سه ژنوتیپ در مقایسه با سایر میوه‌ها رنگی نظیر شاتوتو زغال اخته حاوی مقادیر قابل توجهی آنتوسیانین (60/3927-17/950 میلی‌گرم/ لیتر) و ترکیبات فنلی (35/12-75/9 گرم/ لیتر) بودند که بیانگر خواص سلامت‌بخش این میوه‌های خودرو و بومی می‌باشد. بلحاظ مواد معدنی هر سه ژنوتیپ غنی از ریزمغذی‌های مورد نیاز بدن انسان نظیر پتاسیم، کلسیم، منیزیم و روی بودند.

Phylogeny ofPleiochiton(Melastomataceae, Miconieae): total evidence

The genus Pleiochiton, as traditionally circumscribed, comprises nine species of epiphytic shrubs endemic to the Atlantic Rain Forest in eastern Brazil. We present here the results of the phylogenetic analysis of four plastid DNA regions (accD-psa1, psbK-psbL, ndhF, atpF-atpH), another of nuclear DNA (internal transcribed spacer, ITS) and a third with morphological characters. The datasets were analysed separately and also combined (all plastid regions, ITS + plastid, morphology and all molecular + morphology). These analyses were made in order to access the phylogenetic relationships between the species of Pleiochiton and related species in other genera, and to establish the circumscription of the genus and understand character evolution within the clade. The genus is monophyletic and supported by high jackknife values in all analyses, which showed some resolution if Clidemia blepharodes and C. parasitica were included. The clade comprises the epiphytic species with succulent roots. Most species have a hypodermis with more than one layer of cells, and also glandular trichomes, bracteoles 2.1–5.0 mm long, calyx teeth and hypanthium ratio ranging from 0.4 to 1.2, oval–oblong petals longer than 4.3 mm, and oval–oblong seeds, with a transition zone between the raphal region and testa made up of differentiated cells. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 162, 423–434.

Seed morphology of Erica L. sect. Loxomeria Salisb. ex Benth., sect. Eremocallis Salisb. ex Benth. and sect. Brachycallis I. Hansen, and its systematic implications

Several quantitative and qualitative seed characters of the seven European species of Erica sect. Loxomeria, Eremocallis and Brachycallis were studied. Two main seed types are found based on size and shape: regular ellipsoid or oblong seeds of ca. 0.4 mm for E. ciliaris and the E. tetralix group, and curved to kidney‐shaped seeds of 0.6–0.9 mm for E. cinerea, E. maderensis and E. terminalis. The testa surface in E. ciliaris is reticulate, with indented outer periclinal walls. Erica cinerea has inflated outer anticlinal walls. This character is exclusive for this species within the European (and nearby areas) species of the genus. The seeds of E. maderensis are similar to those of E. terminalis. According to seed morphology, the classical infrageneric classification, by which E. terminalis would be grouped with the E. tetralix group in sect. Eremocallis and E. maderensis in sect. Brachycallis with E. cinerea, is artificial.

Variability of pressure drops in grain generated by kernel shape and bedding method

Experiments were performed to evaluate the influence of seed shape and the packing orientation of seeds on the pressure drop. Relationships between the pressure drop and airflow velocity of five seeds were determined as a function of filling method and its influence on kernel orientation. The sample container was a cube with a length of 0.35 m on each side that held approximately 35 kg of clean wheat. Eleven airflow rates were supplied in a range from 0.03 to 0.35 m s −1. Seeds that were nearly spherical (rapeseed and pea) as well as oblong seeds (wheat, rye and oats) were used for the tests. Three filling methods of the cube were used, including one that produced asymmetric particle orientation (bedding) within the grain sample. Pressure drop was measured in all three directions: the vertical ( Z) and both horizontal directions ( X and Y). Results obtained from the experiments showed that seed shape and the filling method strongly influenced pressure drop. At an air velocity of 0.3 m s −1, when the cube was filled along the vertical axis the uncompacted samples had a pressure drop in the vertical direction that was 1.1 (peas) to 2.1 (oats) times higher than the pressure drops along the X and Y axes. The pressure drops along the X and Y axes were approximately equal. Compaction of the sample filled vertically resulted in the pressure drop in the vertical direction increasing between 1.7 (wheat, rye and peas) and 2.4 (oats) times the pressure drop in the uncompacted sample. In asymmetrically filled samples the pressure drops along the horizontal directions increased by a factor of 2.2 relative to the centrally filled samples.

The South American Dictyophragmus (Brassicaceae)

Two of the approximately 350 South American species of Brassicaceae (Cruciferae) have broadly flattened, linear to linear-lanceolate fruits, broadly winged seeds, and accumbent cotyledons. The first is a Peruvian species described by Muschler (1908) as Streptanthus englerianus Muschler and was later transferred by Schulz (1933) to the monotypic Dictyophragmus 0. E. Schulz. The second is a recently discovered Argentinian species described by Romanczuk (1982) as Sisymbrium punense Romanczuk. Except for the superficial resemblance in fruits and seeds, the two species have little in common with the exclusively North American Streptanthus Nuttall. Because of the common occurrence in unrelated genera of the Brassicaceae of broadly flattened fruits, broadly winged seeds, and accumbent cotyledons, it is safe to conclude that this character combination evolved independently several times within the family. Sisymbrium punense and Dictyophragmus englerianus (Muschler) 0. E. Schulz are glabrous annuals with auriculate to amplexicaul cauline leaves, small, white flowers, confluent nectar glands, entire stigmas, broadly flattened fruits, accumbent cotyledons, and broadly winged seeds. Despite the significant morphological differences and geographical disjunction, the two species are more closely related to each other than to any South American Brassicaceae. In my opinion, their relationship is better understood by placing them in one genus than by recognizing two monotypic genera, of which one should be segregated as new. Perhaps the nearest relative of Dictyophragmus is the South American Eremodraba 0. E. Schulz, a genus of two species, one of which is narrowly endemic to southern Peru and the other restricted to adjacent northern Chile (Al-Shehbaz, 1990). Species of these genera are glabrous annuals with amplexicaul cauline leaves, small flowers, confluent nectar glands, entire stigmas, and flattened fruits. On the basis of differences in the cotyledonary position, Schulz (1936) placed Dictyophragmus in the tribe Arabideae and Eremodraba in the Sisymbrieae. Students of the Brassicaceae now place much less emphasis on the cotyledonary position, and evidently the boundaries between the Arabideae and Sisymbrieae are highly artificial. It is even doubtful that these tribes are distinct or natural. In my opinion, one should be cautious about the rigid use of characters such as the cotyledonary position in assessing relationships at higher taxonomic levels within the family. In addition to the differences in cotyledonary position, Eremodraba has yellow flowers and wingless, plump, oblong seeds. In contrast, Dictyophragmus has white flowers and broadly winged, flattened, orbicular to broadly ovate seeds.