Number Of Stamens Research Articles

<p><strong><em>Amaranthus rajasekharii </em></strong><strong>(Amaranthaceae), a new species from Kerala (SW-India)</strong></p>

A new species of Amaranthus from Kerala (SW-India)—Amaranthus rajasekharii—is described and illustrated. Macro- and micro-morphological descriptions (with SEM analysis of pollen and seed), as well as original photos and drawings were provided. The new species is similar to A. dubius, from which it differs by stem color, inflorescence structure, gynoecium colour, number of stamens, and shape and lenght of tepals and bracts in pistillate flowers, seed ornamentation, and pollen architecture.

Caspian Anadromous Shad Alosa kessleri kessleri (Grimm, 1887) from the Akhtuba River, Lower Volga River Basin: Biological and Morphological Features

Data on the dynamics of anadromous migration, age composition, body length, body weight, and morphometric characteristics of Caspian anadromous shad from the Akhtuba River are presented. Currently, Caspian anadromous shad from the Akhtuba River is monomorphic; no temporal groups have been identified. The population is represented by medium-sized young early-maturing (age of 2–3 years) fish with life longevity less than 5 years. Generally, according to the most important diagnostic signs, first and foremost, to the number of gill stamens and some plastic signs, Caspian anadromous shad from the Akhtuba River falls within the range of the diversity that is typical for the form.

Specialised protagonists in a plant-pollinator interaction: the pollination of Blumenbachia insignis (Loasaceae).

Analyses of resource presentation, floral morphology and pollinator behaviour are essential for understanding specialised plant-pollinator systems. We investigated whether foraging by individual bee pollinators fits the floral morphology and functioning of Blumenbachia insignis, whose flowers are characterised by a nectar scale-staminode complex and pollen release by thigmonastic stamen movements. We described pollen and nectar presentation, analysed the breeding system and the foraging strategy of bee pollinators. We determined the nectar production pattern and documented variations in the longevity of floral phases and stigmatic pollen loads of pollinator-visited and unvisited flowers. Bicolletes indigoticus (Colletidae) was the sole pollinator with females revisiting flowers in staminate and pistillate phases at short intervals, guaranteeing cross-pollen flow. Nectar stored in the nectar scale-staminode complex had a high sugar concentration and was produced continuously in minute amounts (~0.09μl·h-1 ). Pushing the scales outward, bees took up nectar, triggering stamen movements and accelerating pollen presentation. Experimental simulation of this nectar uptake increased the number of moved stamens per hour by a factor of four. Flowers visited by pollinators received six-fold more pollen on the stigma than unvisited flowers, had shortened staminate and pistillate phases and increased fruit and seed set. Flower handling and foraging by Bicolletes indigoticus were consonant with the complex flower morphology and functioning of Blumenbachia insignis. Continuous nectar production in minute quantities but at high sugar concentration influences the pollen foraging of the bees. Partitioning of resources lead to absolute flower fidelity and stereotyped foraging behaviour by the sole effective oligolectic bee pollinator.

CRABS CLAW and SUPERMAN Coordinate Hormone-, Stress-, and Metabolic-Related Gene Expression During Arabidopsis Stamen Development

The appropriate timing of the termination of floral meristem activity (FM determinacy) determines the number of floral organs. In Arabidopsis, two transcription factors, CRABS CRAW (CRC) and SUPERMAN (SUP), play key roles in FM determinacy. CRC belongs to the YABBY transcription factor family, whose members contain a zinc finger and a helix-loop-helix domain. The crc mutation causes the formation of unfused carpels and leads to an increase in carpel number in sensitized backgrounds. The SUP gene encodes a C2H2-type zinc-finger protein, and sup mutants produce extra carpels and stamens. However, the genetic interaction between CRC and SUP is not fully understood. Here, we show that these two transcription factors regulate multiple common downstream genes during stamen development. The crc sup double mutant had significantly more stamens and carpels than the parental lines and an enlarged floral meristem. Transcriptome data have implicated several cytokinin- and auxin-related genes as well as stress- and metabolic-related genes to function downstream of CRC and SUP during stamen development. The regulation of common downstream genes of CRC and SUP might contribute to the initiation of an appropriate number of stamens and to subsequent growth and development.

Floral development in Hura crepitans (Euphorbiaceae): a bat-pollinated species with multicarpellate gynoecium

Hura crepitans L. stands out in the family Euphorbiaceae by being bat-pollinated, having inflorescences with a single female flower with a giant multicarpellate gynoecium at the base of a spike with a large number of male flowers. We described the structure and development of flowers of this species to understand the diversification of flowers in the family and how anatomical structures have adapted to bat pollination. Flower buds and flowers were fixed and embedded in paraffin and studied using scanning electron microscopy. Young male flowers are embedded in the axis of a spike. In both male and female flowers, the calyx is extremely reduced, the sepals united, in male flowers lacking vascularization. Petals are lacking. In male flowers, the androecium has 13–30 united stamens, arranged in (2)3(4) whorls. Female flowers have 11–14 uniovulate united carpels, each with a separate locule. The ovules are pachychalazal with vasculature in both integuments. The style is atro-vinaceous, forming a long column ending in a lobed stigmatic plate. Hura crepitans is similar to Algernonia and Ophthalmoblapton of Hippomaneae in the increased carpel number. However, flowers have some features that allow bat pollination, in contrast to the rest of the family which is more often insect- or wind-pollinated. Among these features are numerous stamen whorls with increased number of stamens, giant gynoecium, reduction in the perianth and a large stigma with central receptive surface.

Dispariflora robertae gen. et sp. nov., a mid-Cretaceous flower of possible Lauralean affinity from Myanmar amber

Three flowers of a fossil angiosperm preserved in amber from Myanmar (Burma) are described as the new genus and species Dispariflora robertae. Although joined in a single cymose inflorescence, the flowers are variable in size and, in addition, they possess an unusual perianth in which 1 sepal is much enlarged and leaf-like, while the remaining 4 are smaller and unequal. The flowers each have 1 superior pistil with a peculiarly plumose and bristly ovary. The number of stamens is uncertain because most were lost before floral preservation, but scars on the receptacle suggest that at least 15 were present. The bithecal anthers open by longitudinal slits and basal glands may have been present on the filaments. Taken as a whole, the floral features that characterize Dispariflora suggest an affinity with members of Laurales, especially several Southern Hemisphere families allied with the Monimiaceae.

Genetic relationship between the ‘Korla fragrant pear’ and local pear varieties in xinjiang based on floral organ characteristics

The characters of floral organ and pollen of local pear varieties in Xinjiang, such as the ‘Korla fragrant pear’ and 39 other varieties or types, Pyrus bretschneideri Rehd., Pyrus pyrifolia Nakai., and Pyrus communis L. were measured and described. The genetic relationships between the ‘Korla fragrant pear’ and other local pear varieties in Xinjiang were analyzed by clustering. The number of flowers per inflorescence of varieties or types was approximately 7.6, and the difference in the number of stamens was small. Except for ‘Aiwenqieke’, ‘Qipanli’ and ‘Daxiangshui’, which had no pollen, the pollen quantity of the varieties or types was 1000.0–5000.0 grains. The pollen grains were isopolar and radiation symmetrical single-grain. The pollen grains had three germination furrows, and the main type of pollen grain exine ornamentation was stripe ornamentation. According to Erdtman’s NPC classification system, the pear pollen was of the N3P4C5 type. According to the clustering results, there was high similarity between the ‘Korla fragrant pear’ and Pyrus sinkiangensis Yü. The ‘Korla fragrant pear’ clustered with most local varieties in Xinjiang, and a genetic relationship between P. bretschneideri and P. pyrifolia was observed. There were interspecific and variety or type differences in floral organ and pollen morphology between P. sinkiangensis and P. bretschneideri, P. pyrifolia, Pyrus ussuriensis Maxim., P. communis and Pyrus betulifolia Bunge. There were many similarities between the ‘Korla fragrant pear’ and local pear varieties in Xinjiang, which should be classified within the P. sinkiangensis system.

Floral Biology and in vitro Germination of Nasturtium Pollen Grains Grown With Poultry Litter

The plant Tropaeolum majus, popularly known as nasturtium, presents food, ornamental and medicinal importance. Studies on floral and carpometric characteristics generate basic knowledge for areas of science such as botany, genetics and plant breeding. This work has the objectives of analyzing the effect of combinations of doses of poultry litter on floral structures and the in vitro germination of T. majus pollen grains. From the experimental matrix Plan Puebla III were defined 9 combinations of poultry litter doses incorporated and covered. The design of the experiments was entirely random, varying the replicates number. The number of stamens, petals, sepals and carpels was verified per floral bud in each treatment. The in vitro germination rate of pollen grains was estimated in 5 culture media and 2 germination times, from flower buds randomly collected in the experiment. The overall mean of stamens, sepals, petals and carpels per floral bud was 8.23; 5; 5 and 3, respectively. The combinations of poultry litter doses influenced only the number of stamens. The in vitro germination rate of T. majus pollen grains varied in the culture media. There was no association between the combinations of poultry litter doses and the in vitro germination rate of pollen grains.

Floral structure and development in Alchornea sidifolia (Acalyphoideae) and the evolution of wind pollination in Euphorbiaceae

Most Euphorbiaceae are insect pollinated, but in Acalyphoideae a considerable number of species are wind pollinated and generally have inconspicuous monochlamydeous flowers with red styles and multifid or laciniate stigmata. Alchornea is within the basal alchorneoid clade, and its flowers are more conspicuous in the group. The aim of this study was to investigate the ontogeny, anatomy and vasculature of flowers of Alchornea sidifolia Mull. Arg., species from the Alchorneoids clade, a basal clade sister of the “core acalyphoid,” in order to find structural aspects related to wind pollination. Flowers and buds of A. sidifolia were embedded in Paraplast and sectioned with a rotary microtome for analysis under light microscopy. SEM was performed for additional structural and ontogenetic data. Alchornea sidifolia is dioecious and has morphologically and functionally unisexual flowers which only share a monochlamydeous, tetramerous perianth, organized in a single whorl of sepals. In the male flower, calyx begins as a ring on the floral meristem in a congenital connation, but in the female one, the calyx has a late synsepaly. Pistillodes and staminodes are absent in the male and female flowers, respectively. The filaments of the stamens are connate at the base for a short extant and free toward the apex. The gynoecium is syncarpous, and the ovary is mostly synascidiate with a short symplicate zone and two long stigmata. Our results highlight the development of features of the inflorescence and flowers of A. sidifolia which in comparison with insect-pollinated Euphorbiaceae display a set of features which are typically associated in many other unrelated angiosperm lineages with the evolution of wind pollination, such as dioecy, production of a higher number of flowers in the male inflorescences than the female inflorescences, unisexual flowers with reduced perianth and no nectaries, male flowers with a variable number of stamens and female flowers with extensive stigmatic receptive surface. We also discuss the presence of two carpels in Alchornea, when most Euphorbiaceae and many other Malpighiales have three, and its relationship with the wind pollination.

Karakter Morfologi dan Sitologi Bunga Pepaya Merah Delima

The papaya plant has three types of flowering, male flowers, female flowers, and perfect flower (hermaphrodite). The difference in interest affects the shape of the resulting fruit. This study aimed to characterize morphology and cytology of papaya flowers. The study was conducted in Tropical Fruit Research Institute at Solok and Laboratory of SPT at the Biology Department of the Faculty of Mathematics and Natural Sciences, Andalas University, Padang, West Sumatra. The research material uses papaya flowers Merah Delima variety from KP. Aripan Balitbu Troipka. The results showed the male flowers of male plants were smaller than the male flowers of the perfect plant. The difference of hermaphrodite flower of pentandria with hermaphrodite elongata flower, among others, the number of stamens, the length of the stem and the size of the ovary. Hermaphrodite pentandria has a number of stamens 5 while elongata has stamens 10

Mitrephora chulabhorniana (Annonaceae), an extraordinary new species from southern Thailand

Mitrephora chulabhorniana, a remarkable new species with the smallest flowers in the genus, is described and illustrated. The new species, from a karst habitat of southern Thailand, morphologically most resembles M. andamanica, which is endemic to the Middle and North Andaman Islands, but differs primarily by having narrower leaves, shorter inner petals, and lower number of stamens and carpels per flower. The conservation status of M. chulabhorniana is assessed and a key to the species of Mitrephora in Thailand is given.

Comparative transcriptomic analysis provides insights into the development of a Salvia splendens Ker-Gawler mutant, SX919M.

Salvia splendens is a perennial, ornamental herbaceous flower that is widely cultivated as a bedding plant in gardens. The development of novel S. splendens cultivars and investigating the relevant molecular mechanisms are of great significance. In this study, RNA-sequencing and real-time PCR methods were used to analyze the possible molecular mechanism of S. splendens mutant, SX919M. From the wild-type S. splendens 919CK, we firstly selected a natural mutant, SX919M, which displayed multiple branches, clustered spheroids, and radial symmetrical inflorescence with higher numbers of calyces, ovules, stamens, and perianth tubes. Further, the RNA-seq was used to identify the differentially expressed genes (DEGs) in the mutant which included a total of 3568 upregulated and 3290 downregulated unigenes. We further observed that the indole alkaloid biosynthesis pathway showed the highest DEG enrichment, which was supported by a significant increase in the IAA content in mutant SX919M. In addition, we validated three DEGs, namely, CL2200.Contig2_All encoding methyl IAA esterase, CL12462.Contig1_All and CL12462.Contig2_All, which encoded strictosidine synthase, upregulated in mutant SX919M. We selected a novel S. splendens germplasm SX919M with a high ornamental value and determined that the upregulation of IAA biogenesis may be associated with its development.

General and Specific Combining Abilities for Flower Characters of Capsicum annuum L.

The study was carried out with the objective of estimating the combinatorial capacity of ornamental pepper (Capsicum. annuum L.) genotypes for flower traits, aiming to identify the best hybrids and the best parents for the synthesis of new populations. The experiment was conducted in a greenhouse in the Biotechnology Laboratory, Agrarian Center, Federal University of Paraíba (Laboratório de Biotecnologia Vegetal of Centro de Ciências Agrárias, Universidade Federal da Paraíba), State of Paraíba, Brazil. Seven accessions of Capsicum annuum were hand-crossed. Seven flower traits were evaluated including days for flowering, flower diameter, petal length, number of petals, number of stamens, anther length, and filament length. The diallel analysis using the Griffing method I of the data recorded showed that accessions 001, 004 and 099 were the best for flower characteristics based on their GCA values. There were significant reciprocal effects for days to flowering, filament length and anther length. The additive effects of the genes were predominant for most of the flower characteristics and the non-additive effects for the days for flowering only. Genotypes 001, 004 and 099 are indicated for crosses that aim to increase flower characteristics. In general, these genitors were involved in almost hybrids combinations with best SCA values. Those combinations should be used for to advance genarations in the breeding program. On the other hand, the best hybrids to be release for propagation were: 134 x 004, 137 x 001, 390 x 004, 77.3 x 099, 001 x 390, 001 x 77.3, and 099 x 77.3.

Oreocharis panzhouensis (Gesneriaceae), a new species from karst regions in Guizhou, China

A new species of Gesneriaceae, Oreocharis panzhouensis, is described and illustrated from Panzhou City, Guizhou Province, China. The new species is morphologically similar to O. cavaleriei and O. forrestii in corolla shape and color, number of stigmas and stamens, but it can be easily distinguished by the shape of leaf blade and calyx, leaf blade indumentum, filament and pistil indumentum and length, and peduncle length.

Flower of the heart, Magnolia yajlachhi (subsect. Talauma, Magnoliaceae), a new species of ceremonial, medicinal, conservation and nurse tree relevance in the Zapotec culture, Sierra Norte de Oaxaca, Mexico

A new species of Magnolia from Sierra de Juárez, Oaxaca, Mexico, is described and illustrated. Magnolia yajlachhi belongs to sect. Talauma, subsect. Talauma, locally known as “yajlachhi” (flower of the heart, in Zapotec). It shares with M. lacandonica the subglobose mature fruit and the entirely white petals, but differs from the latter in having fewer carpels and stamens; more lateral leaf veins per side; and seeds orange vs. scarlet-red. It shares with M. zoquepopolucae the subglobose fruit but differs from the latter in having fewer carpels and stamens; petals entirely white vs. purplish in the upper portion (¾); more lateral leaf-veins per side; and seeds orange vs. scarlet-red. It shares with M. mexicana a similar number of carpels and stamens but it differs from the latter in having subglobose fruits to widely ovoid-depressed vs. widely ellipsoid; more leaf-veins per side; petals entirely white vs. adaxially purplish in the upper portion (¾); and seeds orange vs. scarlet-red. A key to Mexican species of sect. Talauma subsect. Talauma is provided. This species was assessed as Critically Endangered (CR). The species has a ceremonial and medicinal, conservation and nurse tree relevance in the Zapotecan culture.

Evolutionary relationships and taxonomy of Microtea (Microteaceae), a basal lineage in the core Caryophyllales.

The basal position of the small American genus Microtea within the core Caryophyllales was suggested only recently in accordance with molecular phylogeny. However, the specific relationships within the genus were not traced. The results of our phylogenetic analysis based on the matK chloroplast gene suggest the monophyly of Microtea, and Ancistrocarpus and other related genera should be included in it. Microtea is divided into two major sister clades: clade A consisting of M.glochidiata, M.maypurensis and M.tenuifolia, and clade B comprising M.debilis, M.sulcicaulis, M.scabrida, M.celosioides, and M.papillosa. The nrDNA dataset (ITS), although containing only a limited number of accessions, shows the same species number in clade A, and the remaining species studied (M.debilis, M.scabrida and M.celosioides) form clade B. Subgeneric status is assigned to clades A and B corresponding with the names Microteasubgen.Ancistrocarpus subgen. nov. and Microteasubgen.Microtea, respectively. The diagnostic characters at the subgeneric level are as follows: length of pedicels, number of flowers at each node, number of stamens and styles. A multivariate analysis of 13 distinguishing morphological characters supports the results of phylogenetic analysis. All species have similar pericarp and seed ultrasculpture and anatomy, and they share the reticulate pericarp surface (independent of presence or absence of finger-shaped outgrowths on its surface) and rugose or slightly alveolate seed ultrasculpture. On the basis of morphological characters, we accept 10 Microtea species. A checklist includes a new diagnostic key, morphological descriptions and distribution patterns of each species. Galeniacelosioides is the oldest legitimate name available for the plants previously known as Microteapaniculata, for which the combination Microteacelosioides is validated here. The neotypes of Galeniacelosioides and Microteasprengelii were designated from the collections of Prinz Wied at BR. The name M.foliosa is discussed and finally synonymized with M.scabrida. The lectotypes of Ancistrocarpusmaypurensis (≡Microteamaypurensis), Microteadebilisvar.ovata (=M.debilis), M.glochidiata, M.maypurensisvar.angustifolia (=M.tenuifolia), M.glochidiataf.lanceolata (=M.maypurensis), M.longebracteata (=M.celosioides), M.paniculatavar.latifolia (=M.scabrida), M.portoricensis, M.scabrida, M.sulcicaulis, and Potamophilaparviflora (=M.maypurensis) are designated. Microteasulcicaulis is reported for the first time as native to Bolivia, and M.maypurensis is reported from Indonesia (Java), where it is found as an alien plant with an unclear invasion status.

Evolutionary relationships and taxonomy of Microtea (Microteaceae), a basal lineage in the core Caryophyllales

The basal position of the small American genusMicroteawithin the core Caryophyllales was suggested only recently in accordance with molecular phylogeny. However, the specific relationships within the genus were not traced. The results of our phylogenetic analysis based on thematK chloroplast gene suggest the monophyly ofMicrotea, andAncistrocarpusand other related genera should be included in it.Microteais divided into two major sister clades: clade A consisting ofM.glochidiata,M.maypurensisandM.tenuifolia, and clade B comprisingM.debilis,M.sulcicaulis, M.scabrida,M.celosioides, andM.papillosa. The nrDNA dataset (ITS), although containing only a limited number of accessions, shows the same species number in clade A, and the remaining species studied (M.debilis,M.scabridaandM.celosioides) form clade B. Subgeneric status is assigned to clades A and B corresponding with the names Microteasubgen.Ancistrocarpus subgen. nov. and Microteasubgen.Microtea, respectively. The diagnostic characters at the subgeneric level are as follows: length of pedicels, number of flowers at each node, number of stamens and styles. A multivariate analysis of 13 distinguishing morphological characters supports the results of phylogenetic analysis. All species have similar pericarp and seed ultrasculpture and anatomy, and they share the reticulate pericarp surface (independent of presence or absence of finger-shaped outgrowths on its surface) and rugose or slightly alveolate seed ultrasculpture. On the basis of morphological characters, we accept 10Microteaspecies. A checklist includes a new diagnostic key, morphological descriptions and distribution patterns of each species.Galeniacelosioidesis the oldest legitimate name available for the plants previously known asMicroteapaniculata, for which the combinationMicroteacelosioidesis validated here. The neotypes ofGaleniacelosioidesandMicroteasprengeliiwere designated from the collections of Prinz Wied at BR. The nameM.foliosais discussed and finally synonymized withM.scabrida. The lectotypes ofAncistrocarpusmaypurensis(≡Microteamaypurensis), Microteadebilisvar.ovata (=M.debilis),M.glochidiata, M.maypurensisvar.angustifolia (=M.tenuifolia), M.glochidiataf.lanceolata (=M.maypurensis),M.longebracteata(=M.celosioides), M.paniculatavar.latifolia (=M.scabrida),M.portoricensis,M.scabrida,M.sulcicaulis, andPotamophilaparviflora(=M.maypurensis) are designated.Microteasulcicaulisis reported for the first time as native to Bolivia, andM.maypurensisis reported from Indonesia (Java), where it is found as an alien plant with an unclear invasion status.

The genera Bernardia Houst. ex Mill. and Tragia L. (Euphorbiaceae, Acalyphoideae) in Northeastern Brazil

Abstract: Bernardia and Tragia are genera of the subfamily Acalyphoideae, with species occurring in tropical and subtropical regions. Studies concerning those genera are scarce in Brazil, including Northeastern Brazil. The present study was designed to study the taxonomy of species occurring there, and provides illustrations, keys, descriptions, and comments concerning taxonomic affinities, as well as information concerning their geographic distributions and environmental preferences. A total of 13 species were encountered, eight of Bernardia and five of Tragia. Of those, B. hamadryadica and T. cearensis are endemic to Northeastern Brazil and B. celastrinea, B. pulchella, and T. chlorocaulon are new records for the region. The two genera occur in moist Atlantic forests, in forest borders, and anthropically impacted areas. New occurrences were recorded in all of the states, totaling 21 new records. The principal diagnostic characters for distinguish were: the sexuality of the plant (monoecious or dioecious), the presence of foliar glands, the types of inflorescence and trichomes, and the numbers of stamens. Among the 13 species encountered, six are illustrated here for the first time.

Phylogenetic Relationships and Morphological Evolution in the Carnivorous Genus Philcoxia (Plantaginaceae, Gratioleae)

Philcoxia (Plantaginaceae, Gratioleae) is a genus with seven species of small herbs endemic to Brazil. It is characterized by underground stems and petioles, peltate leaves, and zigzag racemose inflorescences, in addition to a remarkable carnivorous syndrome. The phylogenetic placement of Philcoxia within tribe Gratioleae has been uncertain since its discovery due to its unique morphology and limited data from phylogenetic studies. We tested the phylogenetic placement of Philcoxia within Gratioleae, increasing the number of species sampled within both the genus and the rest of the tribe, and sequencing four regions from cpDNA (rpl16, rps16, and trnL introns and the trnL-trnF intergenic spacer) and one from nrDNA (ITS1 spacer); we used both parsimony and Bayesian inference to reconstruct the phylogeny. Moreover, we assessed both the monophyly of the genus and interspecific relationships. Finally, we performed ancestral character state reconstructions of 10 morphological characters to infer synapomorphies for the genus and specific clades within it. Philcoxia was recovered as monophyletic, with maximum support values, as sister to Stemodia stellata. Five morphological character states were reconstructed as potential synapomorphies for the Philcoxia clade (rosetted herb habit, underground stems and petioles, floral resupination, number of stamens reduced to two, and number of fertile thecae per anther reduced to one), whereas fourwere reconstructed as potential synapomorphies for specific clades within the genus (peltate leaves, irregular rosettes, vegetative propagation by rhizomes, and presence of tubers). Further anatomical studies, in association with ecological data, would provide insight into the structure of the underground systems and its adaptive significance, and would further elucidate the evolution of carnivory in Philcoxia. Our study highlights the need to reassess the concepts and circumscriptions of some currently accepted genera of the Gratioleae such as Bacopa, Conobea, and Stemodia, and for the tribe Angelonieae.

СРАВНИТЕЛЬНЫЙ АНАЛИЗ МОРФОМЕТРИЧЕСКИХ ПОКАЗАТЕЛЕЙ СТЕРЛЯДИ ЗИМОВАЛЬНЫХ ЯМ НИЖНЕГО ИРТЫША

The article describes the results of morphometric studies of sterlet caught in water areas of two riverbed depressions of the Lower Irtysh (the Tyumen region) The studies were carried out in the period from 2015-2018, the riverbed depressions were remote from each other: Gornoslinkinskaya (the Uvat region), Kondinskaya (the Khanty-Mansiysk region). The geographic distance (the distance between the riverbed depressions is 445 km) and short migration length (about 200 km) prompted the assumption about the probability of significant discrepancies in the signs that suggest the allocation of any subgroups of sterlet. In the catches of sterlet in the Kondinskaya riverbed depression there were 93 specimens aged 1-4 years old. In the water area of the Gornoslinkinskaya riverbed depression 128 specimens were caught at the age of 1-7 years old. The comparison of sterlet groups from remote riverbed depressions was conducted using meristic signs: the number of bone plates (scutes) rays in the fins, the number of stamens on the first gill arch. According to the research results, it has been stated that there are no significant differences in the number of dorsal, lateral and ventral bone plates. Also, no differences were found in the number of stamens on the first gill arch. The greatest differences in the studied groups of sterlet were recorded in terms of the number of rays in the dorsal and anal fins. Additionally, the meristic features have been estimated by Mayr coefficient (1971), the value of which is equal to or greater than 1.28, which suggests the subspecific division. In our study, Mayr coefficient in all cases was less than 1.28, its maximum value (0.38) was established in studying the number of stamens on the 1-st gill arch. As for the remaining signs, this value is even smaller. Thus, geographical distance (over 400 km) of sterlet groups from the 2 riverbed depressions of the Lower Irtysh should not be taken as a reason to single out any subgroup.