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Atsparumas šalčiui ir ištvermingumas žiemą – pagrindiniai veiksniai, lemiantys augalų geografinį pasiskirstymą. Be to, šie veiksniai turi didžiulę įtaką kultūrinių augalų derlingumui. Braškės, kurios yra tarp svarbiausių uoginių augalų pasaulyje ir Lietuvoje, stipriai pašąla esant nepastoviai sniego dangai, vis dažniau pasitaikančiomis permainingomis žiemojimo sąlygomis. Nepakankamas braškių ištvermingumas žiemą, aiškių kriterijų, kurie leistų per trumpesnį nei kelių metų laikotarpį atrinkti ištvermingas veisles nebuvimas, apsunkina naujų, adaptyvių, derlingų, kokybiškomis uogomis, braškių veislių sukūrimą ir introdukciją. Atsparumo šalčiui mechanizmai intensyviai tirti naudojant modelinius augalus, tačiau žinių apie žiemojančių kultūrinių augalų, kurių įvairovė labai didelė, ištvermingumo žiemą mechanizmus ir jo genetinį reguliavimą labai trūksta. Atsparių šalčiui augalų atrankai vykdyti reikalingos žinios apie augalų užsigrūdinimą, apie atsparumą šalčiui lemiančius veiksnius ir juos kontroliuojančius genus. Tiriant augalus kontroliuojamomis sąlygomis in vitro, galima ištirti atskirų veiksnių įtaką užsigrūdinimui ir atsparumui šalčiui, atsiribojant nuo, neišvengiamo natūraliomis sąlygomis, daugelio įvairių veiksnių poveikio. Braškių užsigrūdinimas ir atsparumas šalčiui svarbūs ne vien tik atrankai. Genetinių išteklių išsaugojimas ateities kartoms - svarbus šiuolaikinės biologijos uždavinys. Didelių kolekcijų išsaugojimą palengvina ir sąnaudas sumažina, augalų laikymas... [toliau žr. visą tekstą] / Cold hardiness and resistance in winter are key factors determining the geographical distribution of plants. In addition, these factors have a huge impact on harvest of cultural plants. Strawberries, which are among the most important berry plants in the world and in Lithuania, are vulnerable to cold because of unstable snow cover, which is more and more often occurring during variable wintering conditions. Insufficient resistance of strawberries in winter, absence of clear criteria, which enable to select the most resistant varieties during a shorter time than the few year period, impedes the development and introduction of new, adaptive, fertile, and of high-quality berries strawberry cultivars. The mechanisms of cold hardiness were intensively investigated using model plants. However, there is a lack of knowledge about the genetic regulation mechanisms of winterhardiness of cultural plants. For the selection of resistant to cold plants, the knowledge about plants cold acclimation and factors determining cold resistance and controlling genes is necessary. Investigating the plants under controlled conditions in vitro, it is possible to investigate the influence of individual factors on acclimation and cold hardiness by disassociating from the influence of many different factors, which is unavoidable under natural conditions. The cold acclimation and cold hardiness of strawberries are important not only for breeding. Preservation of plant genetic resources for future... [to full text]

Several native species of Lauraceae (e.g. sassafras) in the southeastern United States are being eradicated by laurel wilt disease. Laurel wilt is caused by a highly invasive and cryptic ambrosia beetle, Xyleborus glabratus, and its fungal symbiont. The symbiont pathogen is spread during colonization of native Lauraceae. Xyleborus glabratus and the pathogen are remarkably effective at colonizing and killing healthy populations of Lauraceae in a brief time period. Control methods have been unable to slow the spread of laurel wilt disease and X. glabratus populations have been spreading into northern latitudes. Presently, cold temperatures may be the only factor limiting establishment of the beetle in interior populations of sassafras. Empirically derived physiological data from this study were combined with climatic, microhabitat, and host data to model the invasive potential/hazard rate of X. glabratus and laurel wilt in sassafras forests of the United States. Sharing this model data will help land managers, forest health specialists, urban foresters, and landowners make informed proactive management decisions regarding laurel wilt disease.

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Cold hardiness and resistance in winter are key factors determining the geographical distribution of plants. In addition, these factors have a huge impact on harvest of cultural plants. Strawberries, which are among the most important berry plants in the world and in Lithuania, are vulnerable to cold because of unstable snow cover, which is more and more often occurring during variable wintering conditions. Insufficient resistance of strawberries in winter, absence of clear criteria, which enable to select the most resistant varieties during a shorter time than the few year period, impedes the development and introduction of new, adaptive, fertile, and of high-quality berries strawberry cultivars. The mechanisms of cold hardiness were intensively investigated using model plants. However, there is a lack of knowledge about the genetic regulation mechanisms of winterhardiness of cultural plants. For the selection of resistant to cold plants, the knowledge about plants cold acclimation and factors determining cold resistance and controlling genes is necessary. Investigating the plants under controlled conditions in vitro, it is possible to investigate the influence of individual factors on acclimation and cold hardiness by disassociating from the influence of many different factors, which is unavoidable under natural conditions. The cold acclimation and cold hardiness of strawberries are important not only for breeding. Preservation of plant genetic resources for future... [to full text] / Atsparumas šalčiui ir ištvermingumas žiemą – pagrindiniai veiksniai, lemiantys augalų geografinį pasiskirstymą. Be to, šie veiksniai turi didžiulę įtaką kultūrinių augalų derlingumui. Braškės, kurios yra tarp svarbiausių uoginių augalų pasaulyje ir Lietuvoje, stipriai pašąla esant nepastoviai sniego dangai, vis dažniau pasitaikančiomis permainingomis žiemojimo sąlygomis. Nepakankamas braškių ištvermingumas žiemą, aiškių kriterijų, kurie leistų per trumpesnį nei kelių metų laikotarpį atrinkti ištvermingas veisles nebuvimas, apsunkina naujų, adaptyvių, derlingų, kokybiškomis uogomis, braškių veislių sukūrimą ir introdukciją. Atsparumo šalčiui mechanizmai intensyviai tirti naudojant modelinius augalus, tačiau žinių apie žiemojančių kultūrinių augalų, kurių įvairovė labai didelė, ištvermingumo žiemą mechanizmus ir jo genetinį reguliavimą labai trūksta. Atsparių šalčiui augalų atrankai vykdyti reikalingos žinios apie augalų užsigrūdinimą, apie atsparumą šalčiui lemiančius veiksnius ir juos kontroliuojančius genus. Tiriant augalus kontroliuojamomis sąlygomis in vitro, galima ištirti atskirų veiksnių įtaką užsigrūdinimui ir atsparumui šalčiui, atsiribojant nuo, neišvengiamo natūraliomis sąlygomis, daugelio įvairių veiksnių poveikio. Braškių užsigrūdinimas ir atsparumas šalčiui svarbūs ne vien tik atrankai. Genetinių išteklių išsaugojimas ateities kartoms - svarbus šiuolaikinės biologijos uždavinys. Didelių kolekcijų išsaugojimą palengvina ir sąnaudas sumažina, augalų laikymas... [toliau žr. visą tekstą]

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Made available in DSpace on 2016-12-08T16:44:34Z (GMT). No. of bitstreams: 1 PGPV09MA042.pdf: 353135 bytes, checksum: f6e276c764d17f2d788c1c6b5cd1e088 (MD5) Previous issue date: 2009-02-05 / The objective of this study was to evaluate the tolerance of Eucalyptus dunnii Maiden, E. benthamii Maiden & Cambage, E. grandis W. Hill ex Maiden e E. saligna Sm., to low temperature (LT&#8325;&#8320;) of seedings when submitted to diferente rustification periods, using as cold tolerance indicators the contentes of total soluble carbohydrates and proline in the leaves. The work was carried out in the Plant Physiology Laboratory of the Agricultural and Veterinary Sciences Center of the University of Santa Catarona State UDESC. Two experiments were performed using a randomized block design. On the first experimente, (clone K-1007) Eucalyptus dunnii seedlings were submitted to diferente periods rustification (0,7,21 and 42 days) and after each rustification period, the seedling were exposed to diferente sub-zero temperatures (-2°, -4°, -6° and -8°C). On the second experimente, seedlings of species Eucalyprtus dunnii (clone KF 09), E. benthamii (clone ARV 116), E. grandis (clone 360 ) and E. saligna (clone 2864) were submitted to two rustification periods (0 and 21 days) and after each rustification period, the seedlings were exposed to three sub-zero temperatures (-2°, -5° and -8°C). In the both experiments the rustification was performed under a regime of daily and night temperatures of 1°C and 5°C, respectively, with photoperiod of 12h. were evaluated the concentrations of total soluble carvohydrates and proline in the leaves, the LT&#8325;&#8320;, the electric conductivity, and the damage index. The data were submitted to analysis of variance followed by the linear regression analysis, Pearson s correlation and in the experimente 2, as well as, to the Test of Tukey (p<0.05). the data obtained on the first experimente with E. dunnii, showed na invrease in the tolerance of this species to low temperatures with increase of leaf contentes of total soluble carbohydrates when submittedmto a rustification period up to 35 days. It was also observed that there is a relationship between the cold tolerance and the increase of leaf total soluble carbohydrates. On the second experimente, diferences were observed between the species regarding to the cold tolerance. The E. dunnii and E. benthamii presented a higher cold tolerance followed by the E. saligna and E. grandis. However, in all the species studied, it was observed a good relationship between to cold tolertance (lower LT&#8325;&#8320;) with the rustification period and that tolerance was correlated to the increase in the leaf contentes of total soluble carbohydrates. The presence of proline in the leaf tissues was found only in the plants of E. dunnii on first experimente and there was no increase within the rustification period. In both experiments it was not observed any relationship between the leaf proline contente and cold tolerance. It was concluded that the increase of cold tolerance of eucalyptus species, in response to low temperature of the plants, was mostrly due to the increase of total soluble carbohydrates in leaf contentes, rather than to the leaf proline contents / Objetivou-se com este trabalho avaliar a tolerância à baixa temperatura (LT50) em mudas das espécies de Eucalyptus dunnii Maiden, E. benthamii Maiden & Cambage, E. grandis W. Hill ex Maiden e E. saligna Sm., submetidas a diferentes períodos de rustificação, usando como indicadores de tolerância ao frio os teores foliares de carboidratos solúveis totais e prolina. Foram realizados dois experimentos, usando-se o delineamento experimental blocos ao acaso, no Laboratório de Fisiologia Vegetal do Centro de Ciências Agroveterinárias da Universidade do Estado de Santa Catarina UDESC. No primeiro experimento, mudas de Eucalyptus dunnii (clone K-1007) foram submetidas a diferentes períodos de rustificação (0, 7, 21 e 42 dias) e após cada período de rustificação as mudas foram expostas a quatro gradientes de temperatura negativa (-2,-4,-6 e -8ºC). No segundo experimento, mudas das espécies de E. dunnii (clone KF 09), E. benthamii (clone ARV 116), E. grandis (clone 360) e E. saligna (clone 2864) foram submetidos a dois períodos de rustificação (0 e 21 dias), sendo que após cada período de rustificação as mudas foram expostas a três gradientes de temperatura negativa (-2,-5 e -8ºC). Em ambos os experimentos a rustificação foi realizada sob um regime de temperaturas diurnas e noturnas de 1ºC e 5ºC, respectivamente, com fotoperíodo de 12 horas. Foram avaliadas as concentrações foliares de carboidratos solúveis totais e de prolina, o LT50, através da condutividade elétrica, e o índice de dano. Os dados foram submetidos à análise da variância e após a análise de regressão linear, teste de correlação de Pearson e, no experimento 2, também ao teste de Tukey (p<0,05). Os dados obtidos no primeiro experimento, com E. dunnii, demonstram que ocorreu um aumento na tolerância desta espécie a baixas temperaturas observando-se um incremento nos teores foliares de carboidratos solúveis totais até 35 dias de rustificação. Também foi observado que existe uma relação entre a tolerância ao frio e o incremento nos teores foliares de carboidratos solúveis totais. No segundo experimento, houve diferenças entre espécies quanto à tolerância ao frio, sendo que as espécies E. dunnii e E. benthamii apresentaram maior tolerância ao frio seguido das espécies E. saligna e E. grandis. No entanto, em todas as espécies estudadas foi observada uma maior tolerância ao frio (menor LT50) das plantas submetidas à rustificação e que esta tolerância está associada ao incremento nos teores foliares de carboidratos solúveis totais. A presença de prolina nos tecidos foliares foi identificada apenas nas plantas de E. dunnii do primeiro experimento e não houve alteração na concentração com o aumento do período de rustificação. Em ambos os experimentos não foi observada correlação entre os teores foliaresde prolina com a tolerância ao frio. Conclui- e que o aumento da tolerância ao frio de espécies de Eucalyptus, em resposta à rustificação das plantas, deve-se em grande parte ao incremento nos teores foliares de carboidratos solúveis totais e não aos teores foliares de prolina