No description available.

No description available.

Le semis précoce du tournesol, d’un à deux mois par rapport à la période habituelle (Avril dans le sud ouest de la France), a été envisagé pour esquiver les périodes de sécheresses estivales. Cette stratégie conduit à un abaissement des températures de l’ordre de 5 à 10°C durant les premières phases de développement de la culture. L’objectif de ce travail est donc d’identifier des génotypes de tournesol adaptés à des conditions de basses températures en début de cycle, et de fournir des outils pour la sélection de ces nouveaux idéotypes. Dans un premier temps le modèle de culture SUNFLO, développé pour l’analyse des interactions génotype x environnement chez le tournesol, a été utilisé pour identifier par simulation un idéotype pour le semis précoce. Cette étude a révélé que le type variétal valorisant le mieux de semis précoce présente une levée précoce et un cycle tardif. Dans un deuxième temps, la variabilité génétique d’une population de lignées recombinantes de tournesol a été une analysée pour des traits agro-morphologiques et physiologiques caractérisant le développement (vitesse de germination, phénologie) et la croissance à basse température (élongation de l’hypocotyle, production de biomasse, et traits physiologiques impliqués dans la tolérance au froid). L’analyse génétique de ces caractères a permis d’identifier les régions chromosomiques impliquées dans la variation de ces caractères (QTLs) ainsi que les marqueurs moléculaires associés à ces QTLs qui représentent des marqueurs d’intérêts pour la sélection. L’analyse des processus impliqués dans la levée (germination et élongation de l’hypocotyle) montre que la température de base pour l’élongation de l’hypocotyle présente un gain génétique significatif à basse température. Ce trait est sous le contrôle génétique de deux QTLs majeurs dont l’un, qui explique 40% de la variabilité phénotypique observée, est lié au marqueur SSR ORS1128. Le temps thermique du semis à la floraison est un caractère contrôlé par des QTLs spécifiques en conditions de semis précoces, parmi lesquels deux sont colocalisés avec des QTLs identifiés pour des traits relatifs à la levée. L’étude des traits physiologiques impliqués dans la réponse aux basses températures a révélé que le tournesol a un potentiel de sélection pour la tolérance au froid, notamment pour le potentiel osmotique. Le maintien des membranes plasmiques stables à basses températures est également un trait jouant un rôle important dans la tolérance au froid. Un QTL à effet majeur lié au marqueur SSR ORS331_2 a été identifié pour ce trait et pourrait être utilisé pour aider à la sélection de génotypes de tournesol adaptés au froid. / Early sowing to escape the drought during summer was studied in sunflower. Sowing one or two months earlier leads to reduce about 5 to 10°C during first stages of development compared with traditional sowing (April in south parts of France) in this species. The aim of this study is to identify sunflower genotypes adapted for low temperature and to identify tools for selecting them. Firstly the crop model SUNFLO, Which is developed to analyze “genotype x environment” interactions in sunflower, was used to identify by simulation favorable ideotypes for early sowing. Results show that they have to present early emergence and a late development cycle. Then, several experiments were undertaken to study genetic variability for agro-morphologic and physiologic traits under early sowing in sunflower. A population of 95 recombinant inbred lines and their two parents were used at low temperature in all experiments. Germination rate, hypocotyl elongation, biomass production and some physiological traits for cold tolerance were studied. Genetic analyses were performed and genomic regions (QTLs) involved in the variation of these traits as well as SSR markers associated with them were identified. Analysis of physiological processes related to emergence (germination and hypocotyl elongation) show that the base temperature of hypocotyl elongation presents a significant genetic gain at low temperature. This trait is controlled by two major QTLs and one of them explains 40% of the phenotypic variance and contains the SSR marker ORS1128. The thermal time from sowing to flowering is controlled by specific QTLs in early sowing and two of them are collocated with QTLs detected for emergence related-traits. The study of physiological traits implied with response to low temperature showed that sunflower present a high potential for cold tolerance variability, especially for the osmotic potential. The cell membrane stability at low temperature is also an important trait for cold tolerance. A major QTL associated with the SSR marker ORS331_2 was identified for this trait and should be used to select sunflower cold tolerant genotypes.

Submitted by Maria Beatriz Vieira (mbeatriz.vieira@gmail.com) on 2016-08-03T13:55:47Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) tese_pablo_cadore.pdf: 5773635 bytes, checksum: 63fadc0a8749af862e0e0b7a9b075c0c (MD5) / Made available in DSpace on 2016-08-03T13:55:47Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) tese_pablo_cadore.pdf: 5773635 bytes, checksum: 63fadc0a8749af862e0e0b7a9b075c0c (MD5) Previous issue date: 2015-09-28 / Sem bolsa / O arroz é uma cultura de origem tropical amplamente cultivada em uma diversidade de áreas, atualmente é o segundo cereal mais produzido no mundo. A ocorrência de baixas temperaturas é um estresse comum na cultura do arroz em regiões temperadas, portanto a tolerância a baixas temperaturas é uma característica desejável em genótipos brasileiros de arroz cultivados no sul do país, onde as temperaturas baixas prejudicam a germinação, o estabelecimento da lavoura e diminuem o rendimento de grãos. Portanto, este trabalho tem como objetivo estudar o comportamento de cruzamentos de arroz tolerantes e sensíveis para o caráter de tolerância ao frio no estádio de germinação e identificar genes diferencialmente expressos através do transcriptoma. Foram realizados cruzamentos controlados com 5 genitores contrastantes. Os genitores e as populações segregantes em F3 e F4 foram submetidos a tratamentos com diferentes temperaturas (13C e 25C) e comparados quanto ao seu desempenho relativo, medido pela germinação, índice de velocidade de germinação em laboratório e em campo, comprimento do coleóptilo e comprimento da raiz. A análise do transcriptoma foi realizada através do RNAseq de dois genótipos BRS SCS Tio Taka e Oro, submetidos a tratamentos com diferentes temperaturas (13C e 25C). Os resultados indicam que o índice de velocidade de germinação obtido em laboratório, apresenta maior eficiência em identificar genótipos e populações comparado com a avaliação em campo. O comprimento do coleóptilo e o índice de velocidade de germinação são as metodologias mais adequadas pela elevada associação com a germinação em baixas temperaturas. Os resultados das correlações na geração F3 diferem dos resultados apresentados na geração F4, devido a segregação das populações. Na cultivar tolerante Oro, poucos genes tiveram expressão gênica aumentada significativamente. Uma lista de 55 genes com diferença na expressão comuns as duas cultivares e uma lista com 17 genes com diferença na expressão únicos para a cultivar tolerante Oro, foram selecionados devido a respostas desses genes à tolerância ao frio na germinação de arroz. / Rice is a tropical crop widely grown in a variety of areas, is currently the second most-produced cereal in the world. The presence of low temperatures is a common stress in rice crops in temperate regions, so the tolerance to low temperatures is a desirable characteristic in Brazilian rice genotypes cultivated in the south, where low temperatures damage germination, establishment of the crop and decrease grain yield. Therefore, this paper aims to study the behavior of rice crossings tolerant and sensitive to cold tolerance at the germination stage and identify differentially expressed genes through the transcriptome. Controlled crosses with 5 contrasting genotypes were performed. The parents and segregating populations in F3 and F4 were subjected to treatments with different temperatures (13C e 25C) and compared for their relative performance, as measured by germination, germination speed index in the laboratory and in the field, length coleoptile length and root. The transcriptome analysis was performed through the RNAseq two genotypes BRS SCS Tio Taka and Oro, submitted to treatment with different temperatures (13C e 25C). The results show that the germination speed index obtained in the laboratory, has higher efficiency and populations to identify genotypes compared with the field evaluation. The length of the coleoptile and the germination speed index are the most appropriate methodologies due the high association with germination at low temperatures. The results of the correlations in the generation F3 differed from the results shown in the F4 generation due to segregation populations. In tolerant cultivar Oro, few genes have increased gene expression significantly. A list of 55 genes with common expression difference in the two cultivars and a list of 17 genes with only difference in the expression for the tolerant cultivar Oro, were selected due to responses of these genes to cold tolerance in rice germination.

Drosophila suzukii est une drosophile invasive en Europe, Amérique du Nord et Amérique du Sud. Contrairement aux autres espèces de drosophiles, les femelles parasitent les fruits mûrs que les larves consomment, engendrant d’importants dégâts sur les cultures fruitières. Les stratégies mises en place par cette espèce pour tolérer les températures hivernales sous nos latitudes sont encore peu comprises. Par conséquent, l’objectif de ma thèse était d’acquérir des connaissances fondamentales sur la thermotolérance de cette espèce, en m’intéressant notamment à la plasticité de la tolérance au froid et aux mécanismes physiologiques sous-jacents à l’acclimatation. J’ai évalué la thermotolérance basale de D. suzukii en soumettant des adultes et des pupes à un large panel de températures (froides et chaudes). Ces expérimentations ont permis de confirmer que cette espèce était intolérante au froid et que des températures supérieures à 32°C impactaient grandement sa survie. Par la suite, j’ai évalué la plasticité de sa tolérance au froid. Mes travaux ont permis de confirmer que sa thermotolérance était effectivement plastique, puisque l’utilisation de températures fluctuantes ou l’acclimatation permettaient de réduire sa mortalité lors d’expositions aux basses températures. L’acclimatation chez D. suzukii était corrélée à de nombreuses modifications physiologiques, telles que l’accumulation de cryoprotecteurs, un réajustement de la composition des phospholipides membranaires et des réserves lipidiques, une régulation des gènes liés à l’activité des transporteurs ioniques ainsi qu’un maintien de l’homéostasie métabolique. Ces modifications, également observées chez d’autres espèces d’insectes, pourraient être liées à l’augmentation de la tolérance au froid de D. suzukii, jouant probablement un rôle important dans sa survie hivernale et donc dans le succès de son invasion. Ces connaissances acquises sur sa thermobiologie contribueront sans doute à mieux cerner les limites physiologiques de cette espèce et prédire l’évolution de son invasion, ainsi que sa phénologie et les variations de populations au cours des saisons dans les zones déjà envahies. Mes résultats ouvrent également des perspectives intéressantes pour la mise en place de techniques de lutte intégrée contre D. suzukii. / Drosophila suzukii is an invasive pest in Europe, North and South America. Unlike other drosophilids, females oviposit in ripe fruits that larvae consume, provoking important damages on fruit productions. The overwintering strategies of this fly are yet poorly understood. Therefore, the aim of my thesis was to acquire new fundamental knowledge about the thermal biology of this fly, and more specifically the plasticity of its thermal tolerance and the physiological mechanisms underpinning cold acclimation. In order to define its basal thermal tolerance, adults and pupae were subjected to a large set of high and low temperatures. My data confirmed that this pest was chill susceptible, and showed that survival was greatly compromised during exposures above 32°C. Next, I evaluated its thermal tolerance plasticity. My data confirmed the high plasticity of its cold tolerance, as fluctuating thermal regimes and acclimation were able to decrease the mortality due to cold exposures. Acclimation in this species was correlate with several physiological adjustments, such as: cryoprotectant accumulation, remodeling of membrane phospholipids and lipidic reserves, upregulation of genes linked with activity of ionic transporters and maintenance of metabolic homeostasis. Those modifications (which are shared among temperate insect species) are likely linked with cold tolerance increase provoked by acclimation. Therefore, these physiological adjustments could play an important role in its overwintering success in Europe and Canada, which can facilitate its invasion in these regions. These new data will participate to a better understanding of its physiological limits, and are thus of importance for predicting the evolution of its invasion front and its phenology and demographic variations in invaded areas. My results are also of interest regarding the set-up of integrated pest management strategies against this fly.

Tea is the most popular beverage worldwide, second only to water. The United States is the third largest importer of tea in the world, importing a total of about 260 million pounds tea annually. With increased demand for locally sourced food products, questions are raised regarding whether domestic production of tea is feasible. Compared to major tea producing countries with centuries of growing history, tea production in the U.S. is limited and requires research support in many aspects of tea production. The objectives of this study were to investigate plant growth, leaf morphology, and seasonal chemical compositions in tea leaves of nine tea cultivars grown in Mississippi, United States; evaluate the effects of black, blue and red shade nets on plant growth and seasonal leaf quality of tea plants; and investigate the content of mineral nutrients in tea leaves of different cultivars and one cultivar under different colors of shade nets. The nine tested tea cultivars varied in plant growth, leaf morphology, cold tolerance, biochemical composition [including soluble solids, carbohydrates, total polyphenols (TP), free amino acids (AA), L-theanine, and caffeine], and mineral content in tea leaves. Among all cultivars transplanted to the field from one-gallon containers in spring 2017, ‘BL2’ had the greatest plant growth index (PGI) when measured in Feb. 2018 and Feb. 2019, which may be helpful toward suppressing weeds and early establishment of a tea plantation. ‘Christine’s Choice’ had the highest content of nitrogen, phosphorus, sulfur, zinc, iron, and boron, and the second highest content of potassium, calcium, and magnesium. The cultivars evaluated in this study generally adapted well to the local environment. All tea samples collected from the nine cultivars and three seasons were considered suitable for green tea processing with low total polyphenol to free amino acids ratios (TP/AA) ranging from 1.72 to 3.71. When compared to unshaded control, black, blue, and red shade nets increased PGI, net photosynthetic rate, and stomatal conductance, decreased N content in tea leaves, decreased air and leaf surface temperatures in summer and reduced cold damage in winter. Red shade nets were considered helpful for improving green tea quality by increasing the content of L-theanine and free amino acids in tea leaves collected in spring and fall compared to unshaded control.

No description available.

A obtenção de cultivares de arroz de alta produtividade e com tolerância a baixas temperaturas para a zona temperada da América Latina é um dos mais importantes desafios para a agricultura local. Neste trabalho buscou-se estimar parâmetros genéticos visando o entendimento do controle genético de tais caracteres para fins de melhoramento genético. Foram avaliadas 13 linhagens de arroz, separados em dois grupos: Grupo 1 composto de seis linhagens suscetíveis ao frio, e Grupo 2 composto de sete linhagens tolerantes ao frio. Os dois grupos foram cruzados de acordo com o delineamento em dialelo parcial (MIRANDA FILHO; GERALDI, 1984) originando 42 combinações híbridas. Os 55 tratamentos (42 híbridos e 13 genitores) foram avaliados no campo em 2005, em duas épocas de plantio, no Centro Internacional de Agricultura Tropical - CIAT. Utilizou-se um delineamento em blocos casualizados com quatro repetições e parcelas constituídas de uma linha com 17 plantas. Os mesmos tratamentos foram avaliados para tolerância ao frio em câmara de crescimento, em três experimentos, utilizando solo como substrato, temperaturas de 16 °C e 12 °C durante o dia e noite, respectivamente, e fotoperíodo de 12 horas com luz artificial. Utilizou-se o mesmo delineamento experimental, com três repetições e parcelas constituídas de uma linha com 20 sementes. Os resultados mostraram a existência de heterose para todos os caracteres agronômicos (altura da planta, número de perfilhos, comprimento da panícula, número de grãos por panícula, porcentagem de esterilidade e peso de 1.000 grãos) e de tolerância ao frio (índice de emergência e produção de matéria seca). O sentido da dominância foi negativo para dias para florescimento e positivo para os demais caracteres, com contribuições desiguais dos genitores para a heterose média. Os efeitos da capacidade geral de combinação (CGC) e da capacidade específica de combinação (CEC) foram importantes para todos os caracteres; entretanto, a CGC foi mais importante que a CEC. Os dois grupos de genitores têm alelos favoráveis para os caracteres agronômicos e para a tolerância. Algumas linhagens como Irga 417 e FL03188 do Grupo 1, FL04423, FL04402, e FL04452 do Grupo 2 apresentaram os menores índices de esterilidade nos cruzamentos intra-grupos. Os genótipos CT6748, Quilla 173201 e Quilla 145601 foram os mais tolerantes a baixas temperaturas e, portanto, promissores para serem utilizados em programas de melhoramento genético de arroz para condições de baixas temperaturas. / The development of high yielding and cold tolerant rice cultivars for the temperate region of Latin America is one of the most important challenges for the local agriculture. The objective of the present work was to estimate the genetic and phenotypic parameters related to the control of cold tolerance and agronomic traits, in order to obtain a better understanding of the genetic control of these traits for breeding purposes. The genetic material comprised two sets of rice lines: Group 1 composed by six cold susceptible lines and Group 2 composed by seven cold tolerant lines. The two groups were crossed according a partial diallel design (MIRANDA FILHO; GERALDI, 1984) giving rise to 42 hybrid combinations. The 55 entries (42 crosses plus 13 parents) were evaluated in 2005 under field conditions, at the International Center for Tropical Agriculture - CIAT, in a randomized complete block design with four replicates, in two planting dates; plots were single-rows with 17 plants. The same entries were evaluated for cold tolerance in growth chambers, in three experiments, using soil as substrate, temperature of 16 °C and 12 °C during the day and night, respectively, and photoperiod of 12 hours using artificial lights. The experimental design was the same with three replications per experiment; and plots were single-rows with 20 seeds. General results revealed the presence of heterosis for the agronomic traits (plant height, tiller number, days to flowering, panicle length, grains by panicle, sterility and one-thousand grain weight) as well as for cold tolerance traits (emergence index and dry matter production), with different contributions of the parents to the mean heterosis effect. The direction of the dominance was negative for days to flowering and positive for all others traits. General combining ability (GCA) and specific combining ability (SCA) were important for all traits; however, the GCA was more important than SCA. Both groups showed the presence of favorable alleles for agronomic and cold tolerance traits. Several lines such as Irga 417 and FL03188 from the Group 1, FL04423, FL04402, and FL04452 from the Group 2, presented lower sterility in the inter-group crosses. The tolerant lines, CT6748, Quilla 173201 and Quilla 145601 were considered the best parents to be used as cold tolerant donors in rice breeding programs.

Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2018-02-23T14:06:29Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) TESE - Rodrigo Danielowski.pdf: 1128627 bytes, checksum: ca7f06026487748000d1d79e7d2bed45 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2018-03-05T20:58:55Z (GMT) No. of bitstreams: 2 TESE - Rodrigo Danielowski.pdf: 1128627 bytes, checksum: ca7f06026487748000d1d79e7d2bed45 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-03-05T20:58:55Z (GMT). No. of bitstreams: 2 TESE - Rodrigo Danielowski.pdf: 1128627 bytes, checksum: ca7f06026487748000d1d79e7d2bed45 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-12-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Este trabalho teve o objetivo de avaliar por meio de modelos biométricos, características agronômicas e de reação ao estresse por frio na germinação de cruzamentos e linhagens formadas a partir de sete cruzamentos de genótipos de arroz. O experimento foi conduzido no campo experimental da Embrapa Clima Temperado, Estação Experimental Terras Baixas e no Centro de Genômica e Fitomelhoramento da Faculdade de Agronomia Eliseu Maciel, os dois locais no município do Capão do Leão/RS. Os cruzamentos e linhagens foram derivadas das seguintes formações: BRS Atalanta x LTB 06012; BRS Atalanta x SCS BRS Tio Taka; BRS Atalanta x BRS Chuí; BRS Chuí x LTB 06012; BRS Chuí x Oro; Oro x SCS BRS Tio Taka; SCS BRS Tio Taka x LTB 06012. As sementes foram conduzidas até a geração F4, quando então foram utilizadas nestes experimentos. As famílias de cada cruzamento foram semeadas em delineamento de linhas com pais intercalares em dois blocos. Em cada parcela foram marcadas 10 plantas para a coleta dos dados morfológicos e posteriormente avaliações de componentes de rendimento em laboratório. Cada planta marcada deu origem as sementes F5, que do cruzamento Oro x SCS BRS Tio Taka deram origem as 170 linhagens avaliadas em laboratório em função do estresse por frio durante a germinação. O experimento para a avaliação quanto a reação ao estresse por frio das linhagens foi montado em delineamento de blocos aumentados de Federer. Foram utilizadas duas câmaras do tipo BOD, uma com temperatura de 25°C e duração de 7 dias e outra a 13°C com duração de 28 dias. Foram avaliados o comprimento de parte aérea, raiz e coleóptilo, além da contagem de sementes germinadas aos 14 e 21 dias para o tratamento com frio. A estimação dos componentes de variância obtidos a partir dos dados a campo resultou na obtenção de parâmetros genéticos e de variância entre e dentro das famílias com diferentes níveis de herdabilidade para os caracteres estudados em cada cruzamento, sendo a seleção baseada na família a que resultará em maior sucesso na seleção. A avaliação de diferentes grupos de caracteres possibilitou o estudo das correlações canônicas, onde foi possível detectar a dependência entre o grupo de variáveis morfoagronômicas com os parâmetros de rendimento de grãos em todos os cruzamentos avaliados. Com a avaliação das linhagens em resposta ao estresse por frio, foi possível detectar efeito significativo entre as linhagens estudadas para quase todas as variáveis analisadas no tratamento controle e no tratamento sob estresse por frio. Para o cruzamento entre as cultivares Oro e SCS BRS Tio Taka foi possível concluir que; a seleção baseada na família resultará em maior sucesso no melhoramento dos caracteres agronômicos; as correlações obtidas revelaram que a seleção baseada no aumento do comprimento de panícula e na redução do ciclo, resultam em aumento da massa total de grãos; para a reação ao estresse por frio durante a germinação, um total de 104 linhagens foram potencialmente tolerantes, sendo que 13 destas foram superiores a cultivar tolerante (Oro) na avaliação da redução do comprimento de coleóptilo. / The objective of this study was to evaluate, through biometric models, agronomic characteristics and reaction to cold stress on germination in populations and lineages formed from seven crosses of rice genotypes. The experiment was conducted in the experimental field of Embrapa Clima Temperado, Estação Experimental Terras Baixas and in Genomics and Plant Breeding Center at Faculty of Agronomy Eliseu Maciel, the two locations in the Capão do Leão / RS. The crosses and lineages were derived from the following formations: BRS Atalanta x LTB 06012; BRS Atalanta x SCS BRS Tio Taka; BRS Atalanta x BRS Chuí; BRS Chuí x LTB 06012; BRS Chuí x Oro; Oro x SCS BRS Tio Taka; SCS BRS TIO Taka x LTB 06012. Seeds were conducted until the F4 generation, when they were used in these experiments. The families of each crossing were sown in the design of lines with intercalated parents in two blocks. In each plot 10 plants were marked for the collection of morphological data and later evaluations of yield components in the laboratory. Each labeled plant gave rise to seeds F5, that of the crossing Oro x SCS BRS Tio Taka gave rise to the 170 lines evaluated in the laboratory as a function of cold stress during germination. The experiment to evaluate the cold stress reaction of the lineages was set up in a Federer augmented block design. Two BOD chambers were used, one with a temperature of 25°C and duration of 7 days and another at 13°C with duration of 28 days. the length of aerial part, root and coleoptile, as well as germinated seed counts were evaluated at 14 and 21 days for cold treatment. The estimation of variance components obtained from the field data resulted in obtaining genetic parameters and components of variance between and within populations with different levels of heritability for the characters studied in each population, being the selection based on the family that will be the most successful in the selection. The evaluation of different groups of characters enabled the study of canonical correlations, where it was possible to detect the dependence between the group of morpho-agronomic variables and grain yield parameters in all the evaluated crosses. With the evaluation of the lineages in response to cold stress, it was possible to detect a significant effect among the studied lineages for almost all the variables analyzed in the control treatment and in the treatment under cold stress. For the cross between the cultivars Oro and SCS BRS Tio Taka it was possible to conclude that: family-based selection will result in greater success in improving agronomic traits; the correlations revealed that the selection based on the increase of the panicle length and the reduction of the days for the flowering, results in an increase of the total mass of grains; for the reaction to cold stress during germination, a total of 104 lines were potentially tolerant, 13 of which were superior to the tolerant cultivar (Oro) in the evaluation of coleoptile length reduction.

The thesis deals with ecophysiology of overwintering larvae of two butterfly genera, Colias and Erebia. It focuses on identification of supercooling point, survival of various low temperature regimes and composition of cryoprotective substances. Results are presented in the context of distributional limits of individual species, their habitat requirements and their potential endangerment due to environmental and habitat changes.