Hariliku saare (Fraxinus excelsior) seisundi hinnang 5 aastat pärast saaresurma tekitaja (Hymenoscyphus pseudoalbidus) esmaavastamist Eestis
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Kuupäev
2014
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Autorid
Ajakirja pealkiri
Ajakirja ISSN
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Kirjastaja
Abstrakt
Eestis ja ka paljudes teistes Euroopa riikides on täheldatud hariliku saare (Fraxinus exelcior L.) ulatuslikku allakäiku, mis on nüüdseks seostatud parasiitse kottseenega, Hymenoscyphus pseudoalbidus (anamorf Chalara fraxinea). Antud töö põhieesmärgiks oli hariliku saare tervisliku seisundi hindamine kolmes Eesti regioonis - Lääne-, Viljandi- ja Jõgevamaal, pidades silmas eelkõige saaresurma kahjustusi. Lisaks analüüsiti võimaliku saarte suremise põhjusena perekond külmaseent (Armillaria spp.). Hinnati ka hariliku saare ja kolme eksoot-saareliigi seemnete kvaliteeti ja idanemist.
Proovialadel hinnati visuaalselt harilike saarte tervislikku seisundit ja saare järelkasvu olemasolu, arvukust ja elujõulisust. Samuti koguti hariliku saare leherootse (võimalusel H. pseudoalbidus’e viljakehadega) ning külmaseente viljakehi. Laboris hinnati H. pseudoalbidus’e viljakehade arvukust ja seene eoste produktsiooni, samuti määrati kindlaks proovialadelt kogutud külmaseente täpne liigiline kuuluvus.
Järelkasvu arvukuses statistiliselt olulist erinevust proovialade vahel ei olnud, küll aga oli oluline erinevus haigustunnustega järelkasvu arvukuses – Luua proovialal Jõgevamaal oli haigeid taimi oluliselt vähem, kui Viljandi- ja Läänemaal. Vanade saarepuude seisukord oli kõige halvem Läänemaal, kus 54% hinnatud saartest oli surnud. Viljandimaal oli surnud saari kõige vähem, s.o 26%.
Põhiliselt leidus proovialadel kahjustatud saartel tutt-külmaseent (Armillaria cepistipes). Kõige rohkem külmaseent leidus Jõgevamaal. Viljandimaal oli külmaseene viljakehi vaid vähesel määral ning Läänemaal ei leitud viljakehi ega puu tüvedelt risomorfe.
Saaresurma tekitaja eoste produktsiooni ja viljakehade arvukust võrreldes ilmnes, et viljakehade tekkega ei kaasne kohest eoste küpsemist, vaid see toimub peaaegu nädalase nihkega peale viljakehade teket. Saaresurma tekitaja eoste arvukuse ajaliste kõikumiste kohta võib leida seoseid varasemate uuringutega ja ilmselt need muutused tulenevad ilmastikutingimustest. Saaresurma tekitaja eoste produktsiooni ja ilmaandmete vahelisi seoseid antud töös ei uuritud.
Lately extensive dieback of common ash (Fraxinus exelcior L.) has been noted in Estonia as well as in many other European countries. For now, ash dieback has been found to be related with parasitic fungus Hymenoscyphus pseudoalbidus (anamorph Chalara fraxinea). The main purpose of this thesis is to evaluate the condition of common ash, in three Estonian regions – at Jõgeva, Viljandi and Lääne county. Besides that, potential connection between two main causers of dying ashes, ash dieback (caused H. pseudoalbidus) and Armillaria spp., was analysed. No similar health condition of common ashes has yet been conducted in Estonia. This subject is important, on the reason, that common ash as our native species holds great importance as part of our biodiversity. Its drastic decrease would mean loss or depletion with many species and communities related to it. Condition of common ash was visually evalueated at chosen test sites, as well as existance, numerousness and viability of the ash regeneration. Samples of symptomatical ash petioles (with apothecia of H. pseudoalbidus) and Armillaria spp. fruit bodies were collected. In laboratory, the numerousness of apothecia of H. pseudoalbidus and production of ascospores was evaluated. Also, definite species of Armillaria were determined. There was no statistically significant difference in numerousness of ash regeneration between sampling areas, however there was significant difference in percentage of symptomatic ash regeneration. At Luua sampling area in Jõgeva county, ash regeneration was much healthier than at other sampling areas. Condition of old trees was the worst at Läänemaa sampling area, where 54 % of total evaluated ashes were dead. At Viljandimaa sampling area, old trees were the healthiest, percentage of dead ashes was 26%. To compare the ascospores production of H. pseudoalbidus and the numerousness of apothecia on ash petioles, it became evident, that the spores discharge didn’t happen at the same time when was the highest number of apothecia on petioles. It seems that spores are matured a week after the formation of apothecia.
Lately extensive dieback of common ash (Fraxinus exelcior L.) has been noted in Estonia as well as in many other European countries. For now, ash dieback has been found to be related with parasitic fungus Hymenoscyphus pseudoalbidus (anamorph Chalara fraxinea). The main purpose of this thesis is to evaluate the condition of common ash, in three Estonian regions – at Jõgeva, Viljandi and Lääne county. Besides that, potential connection between two main causers of dying ashes, ash dieback (caused H. pseudoalbidus) and Armillaria spp., was analysed. No similar health condition of common ashes has yet been conducted in Estonia. This subject is important, on the reason, that common ash as our native species holds great importance as part of our biodiversity. Its drastic decrease would mean loss or depletion with many species and communities related to it. Condition of common ash was visually evalueated at chosen test sites, as well as existance, numerousness and viability of the ash regeneration. Samples of symptomatical ash petioles (with apothecia of H. pseudoalbidus) and Armillaria spp. fruit bodies were collected. In laboratory, the numerousness of apothecia of H. pseudoalbidus and production of ascospores was evaluated. Also, definite species of Armillaria were determined. There was no statistically significant difference in numerousness of ash regeneration between sampling areas, however there was significant difference in percentage of symptomatic ash regeneration. At Luua sampling area in Jõgeva county, ash regeneration was much healthier than at other sampling areas. Condition of old trees was the worst at Läänemaa sampling area, where 54 % of total evaluated ashes were dead. At Viljandimaa sampling area, old trees were the healthiest, percentage of dead ashes was 26%. To compare the ascospores production of H. pseudoalbidus and the numerousness of apothecia on ash petioles, it became evident, that the spores discharge didn’t happen at the same time when was the highest number of apothecia on petioles. It seems that spores are matured a week after the formation of apothecia.
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