4 research outputs found
Influence of ecological factors on arbuscular mycorrhizal symbiosis in natural habitats and agrocenoses
No full textArbuskulÄro mikorizu ietekmÄjoÅ”ie ekoloÄ£iskie faktori dabiskos biotopos un agrocenozÄs
KOPSAVILKUMS
Å Ä« darba mÄrÄ·is bija noskaidrot arbuskulÄro mikorizu (AM) ietekmÄjoÅ”os ekoloÄ£iskos faktorus dažÄdos dabiskos un antropogÄni ietekmÄtos biotopos, kÄ arÄ« noskaidrot arbuskulÄrÄs mikorizas sÄÅu daudzveidÄ«bu un sastopamÄ«bu. KopumÄ veikti seÅ”i pÄtÄ«jumi dabiskos biotopos un lauksaimniecÄ«bÄ izmantotÄs zemÄs. DarbÄ izmantota standarta metodika, kas ir atzÄ«ta par piemÄrotu arbuskulÄrÄs mikorizas pÄtÄ«jumiem. PÄtÄ«to parametru ietekme novÄrtÄta ar vispÄrinÄto lineÄro modeļu (GLM) metodi. Gradienti noskaidroti ar CCA (canonical correspondance analysis) metodi. PÄtÄ«jumu rezultÄtÄ noskaidrots, ka bÅ«tiskie biotiskie arbuskulÄro mikorizu ietekmÄjoÅ”ie faktori ir saimniekauga suga un tÄ sakÅu morfoloÄ£iskÄs Ä«patnÄ«bas. NovÄrotas atŔķirÄ«bas starp arbuskulÄro mikorizu ietekmÄjoÅ”o faktoru bÅ«tiskumu dažÄdos biotopos, kÄ arÄ« to ietekmes variÄcijas dažÄdos gados. KonstatÄts, ka vieni no galvenajiem faktoriem, kas ietekmÄ sÄÅu aktivitÄti saknÄs un sporu veidoÅ”anos augsnÄ, ir augsnes granulometriskais sastÄvs un pH. Noskaidrots, ka sporu veidoÅ”anÄs nav atkarÄ«ga no sakÅu kolonizÄcijas intensitÄtes. AnalizÄjot AM sabiedrÄ«bas struktÅ«ru 21 LatvijÄ rajonÄtai Hordeum vulgare Ŕķirnei, noskaidrots, ka vecÄkÄm ŔķirnÄm mikorizÄlÄ aktivitÄte ir lielÄka. No 43 pÄtÄ«tajÄm briofÄ«tu sugÄm simbioze konstatÄta tikai seÅ”Äm vienkÄrÅ”Ä un saliktÄ lapoÅa aknu sÅ«nÄm. PÄtÄ«tajos biotopos konstatÄtas 13 sporulÄjoÅ”as arbuskulÄrÄs mikorizas sÄÅu sugas. No tÄm visbiežÄk sastopamÄs sugas ir Glomus intraradices un Glomus mossae. Å Ä pÄtÄ«juma ietvaros iegÅ«tie dati par arbuskulÄrÄs mikorizas daudzveidÄ«bu un to ietekmÄjoÅ”iem faktoriem apstiprina, ka simbioze ir sarežģīta, kompleksa sistÄma, tÄdÄļ nepiecieÅ”ami turpmÄki pÄtÄ«jumi, lai produktÄ«vi izmantotu informÄciju par mikorizu sabiedrÄ«bÄm kÄ ekoloÄ£iskiem indikatoriem biotopu kvalitÄtes noteikÅ”anÄ un bioloÄ£iskÄs daudzveidÄ«bas monitoringÄ.
Promocijas darbs izstrÄdÄts Latvijas UniversitÄtes BioloÄ£ijas institÅ«tÄ un BioloÄ£ijas fakultÄtes BotÄnikas un ekoloÄ£ijas katedrÄ laika posmÄ no 1996. gada lÄ«dz 2008. gadam.
AtslÄgas vÄrdi: arbuskulÄrÄ mikoriza, Glomeromycota, biotopi, ekoloÄ£iskie faktori, saimniekaugsSUMMARY
Influence of ecological factors on arbuscular mycorrhizal symbiosis in natural habitats and agrocenoses
The main objective of the present work was to determine the ecological factors affecting the arbuscular mycorrhiza (AM) in various natural and anthropologically affected habitats, as well as to determine the diversity and occurrence of arbuscular mycorrhizal fungi. Altogether six studies were carried out in natural biotopes and agricultural lands. The methods used to perform the work are acknowledged as fitting for arbuscular mycorrhizal research. The influence of the examined parameters was evaluated using the method of generalized linear models (GLM). The gradients were determined using the canonical correspondence analysis (CCA). The results of the research testify that the most important biotic factors affecting the arbuscular mycorrhiza are the host plant identity (species) and the morphological features of its roots. Differences were found among the relevance levels of the factors affecting arbuscular mycorrhiza in various habitats, and variations were detected among the results obtained in different years. The granulometric composition of soil and pH values have been found to be among the main factors affecting the fungal activity in roots and the formation of spores in soil. It has been established, that the formation of spores is not dependent on the intensity of root colonization. The analysis of the structure of AM communities in 21 cultivars of Hordeum vulgare approved in Latvia reveals that mycorrhizal activity is higher in older cultivars. Symbiosis was detected only for six simple an complex thalloid liverwort species out of 43 examined bryophyte species, In total13 species of sporulating arbuscular mycorrhizal fungi were found in the investigated habitats. The most common were the fungi of the genus Glomus ā G. intraradices and G. mossae. The data obtained in these studies about the diversity of arbuscular mycorrhiza and the factors affecting it confirm that symbiosis is a very complex system, therefore further research is needed to effectively use the information about mycorrhizal communities as ecological indicators in the determination of habitat quality and monitoring of biodiversity.
The doctoral thesis was conducted in the Institute of Biology of the University of Latvia and the Faculty of Biology, Department of Botany and Ecology, from 1996 to 2008.
Keywords: Arbuscular mycorrhiza, Glomeromycota, habitats, ecological factors, host plan
Diversity of non-forest plant communities on the verges of roads of local importance
No full textLigitas LiepiÅas bakalaura darba āNemeža augu sabiedrÄ«bu daudzveidÄ«ba uz lokÄlas nozÄ«mes autoceļu nomalÄmā mÄrÄ·is ir noskaidrot, cik liela nemeža augu sabiedrÄ«bu daudzveidÄ«ba spÄj izveidoties uz lokÄlas nozÄ«mes neintensÄ«vi lietota autoceļa nomalÄm un kÄdi vides faktori to ietekmÄ. PÄtÄ«jums veikts balsoties uz 2014.gada jÅ«lijÄ un augustÄ iegÅ«tiem datiem. PÄtÄ«juma teritorijÄ aprakstÄ«ti 198 parauglaukumi un 160 sugas; no tÄm 18 ir bioloÄ£iski vÄrtÄ«go zÄlÄju indikatorsugas. AnalizÄjot iegÅ«tos datus, noskaidrots, ka pÄtÄ«juma vietÄ sastopamas 3 nemeža sabiedrÄ«bas, to izplatÄ«bu ietekmÄ temperatÅ«ras, gaismas un kontinentalitÄtes faktori.
Ligitas LiepiÅas bakalaura darbs sastÄv no 4 nodaļÄm un apakÅ”nodaļÄm, to papildina 12 attÄli un 3 pielikumi. Darba apjoms ir 38 lapaspuses.Aim of bachelor thesis of Ligita LiepiÅa āDiversity of non-forest plant communities on the verges of roads of local importanceā is to find out how large the diversity of non-forest plant communities is able to develop on not intensively used local importance road verges and what environmental factors affects it. The study was carried out on the basis of data obtained on July and August 2014. In research territory there was 198 sample plots and 160 species described; 18 of them are indicator species of biologically valuable grasslands. Analyzing the obtained data showed, that 3 non-forest communties are found on the research site, their spreading is affected by temperature, light and continentality factors.
Bachelor thesis of Ligita LiepiÅa consists of 4 chapters and subchapters, supplemented with 12 images and 3 attachments. The volume of work is 38 pages
Maritime Research Supported by European Union
No full textPÄtÄ«jumÄ izklÄstÄ«tas iespÄjas, ko Å”obrÄ«d sniedz ar jÅ«rniecÄ«bu saistÄ«ti pÄtniecÄ«bas un attÄ«stÄ«bas projekti EiropÄ kopÄjÄ Eiropas jÅ«rniecÄ«bas vadlÄ«niju kontekstÄ. TÄpat pÄtÄ«jumÄ aprakstÄ«tas atbalsta iespÄjas no ES Ietvara ProgrammÄm (IP), kÄ arÄ« tÄdÄm pÄtniecÄ«bas programmÄm, kÄ COST, EUREKA un INTERREG, kÄ arÄ« Å”o programmu ietekme uz jÅ«rniecÄ«bas sektoru. PlaÅ”s pÄrskats par 6.IP jÅ«rniecÄ«bas projektiem un Latvijas partneru dalÄ«bu tajÄ tiek apkopots, vienlaikus analizÄjot tematiskÄs prioritÄtes, kurÄs sekmÄ«gi tiek finansÄti jÅ«rniecÄ«bas pÄtÄ«jumu projekti. Par piemÄru var minÄt tÄdus EK finansÄtos projektus, kÄ ENCOMAR-TRANSPORT un EROMAR-BRIDGE, kuru mÄrÄ·is ir veicinÄt informÄtÄ«bu par ES atbalstÄ«tÄm pÄtniecÄ«bas iespÄjÄm
Arbuscular mycorrhizal colonization in roots of sand dune plants in relation to soil factors
No full textAbstract Seacoast plant communities represent primary successions characterized by a harsh environment in which mycorrhizal symbioses are known to be important for plant survival and growth. The study was carried in two grey dune areas (Užava and PÄvilosta) on the western coast of Latvia by the Baltic Sea. We examined how root colonization and abundance of arbuscular mycorrhiza differed along a primary dune succession from an early successional primary dune to an overgrowing grey dune, in relation to soil factors. We hypothesized that plant species growing on soil with a poorly developed soil horizon and low C, P and N concentration would have a higher extent of arbuscular mycorrhiza colonization. We also tested the relationship of soil factors and fungal abundance in roots within specific plant species. In a total of 93 plots among 5 habitats, we determined soil carbon, phosphorus and nitrogen concentrations and sampled roots of dominant plants for determination of arbuscular mycorrhizal (vesicules and hyphae) frequency, abundance of arbuscular mycorrhizal vesicules and hyphae, and abundance of arbuscules. The results showed that extent of mycorrhizal colonization was related to soil development, being more important in the most nutrient poor habitats, compared to grassland habitats. However, slight increases in P and N concentration were associated in increased mycorrhizal colonization in early successional stages and disturbed habitats
