The effect of enhanced UV-B radiation on Norway spruce (Picea abies (L.) Karst) in posledice za gorski gozdni ekosistem

Rastline, ki uspevajo v gorah, so pogosto izpostavljene stresnim razmeram, predvsem povečani jakosti sevanja UV-B, skrajnim temperaturnim razmeram ter pomanjkanju vode in hranil. Odziv smreke na okoljske razmere je kompleksen. Pri enoletnih iglicah v visokogorju smo izmerili manjšo fotokemično učinkovitost in vsebnost klorofilov, kar kaže na občutljivost mladih iglic, kjer zaščitni mehanizmi še niso dokončno razviti. Pri starejših iglicah razlika ni bila več statistično značilna, zato sklepamo, da se poškodbe v drugem in tretjem letu preprečijo ali popravijo. Pri dveletnih iglicah smreke z visokogorskega rastišča je bil dihalni potencial značilno manjši in vsebnostUV-B absorbirajočih snovi značilno večja, kar pojasnjujemo s tem, da so dveletne iglice z visokogorskega rastišča med tremi starostnimi razredi najbolj odporne proti UV-B sevanju. Iz rezultatov sicer ne moremo sklepati, v kolikšni meri je k odzivu rastline prispeval posamezni stresni dejavnik, vendar lahko trdimo, da je smreka razmeroma dobro prilagojena na velike jakosti UV-B sevanja in stresne razmere, kakršne vladajo v visokogorju.Norway spruce trees from the subalpine stand are exposed not only to high UV-B radiation but also to a complex of other environmental factors, suchas high photosynthetically active radiation, extreme temperature conditions, deficient water and mineral supply, which might cause stress responses. Current year needles from the subalpine stand exhibited lower photochemical efficiency and total chlorophyll content compared to samples from lower altitudes. The result suggested that young needles were most vulnerable to stress factors, since the protective mechanisms were not fully developed. Current+1 year needles from the subalpine stand exhibited lower ETSvalues and higher total UV-B absorbing compounds, which may be interpreted as most successful protection against UVB radiation of current+1 year needles among the three needle age classes. Despite the obtained results, the effect of a single stress factor on spruce could not be easily drawn out. Still, we may assume that the spruce is quite tolerant to high UV-B radiation and other extreme environmental factors in the mountains

The effect of enhanced UV-B radiation on Norway spruce (Picea abies (L.) Karst) in posledice za gorski gozdni ekosistem

Rastline, ki uspevajo v gorah, so pogosto izpostavljene stresnim razmeram, predvsem povečani jakosti sevanja UV-B, skrajnim temperaturnim razmeram ter pomanjkanju vode in hranil. Odziv smreke na okoljske razmere je kompleksen. Pri enoletnih iglicah v visokogorju smo izmerili manjšo fotokemično učinkovitost in vsebnost klorofilov, kar kaže na občutljivost mladih iglic, kjer zaščitni mehanizmi še niso dokončno razviti. Pri starejših iglicah razlika ni bila več statistično značilna, zato sklepamo, da se poškodbe v drugem in tretjem letu preprečijo ali popravijo. Pri dveletnih iglicah smreke z visokogorskega rastišča je bil dihalni potencial značilno manjši in vsebnostUV-B absorbirajočih snovi značilno večja, kar pojasnjujemo s tem, da so dveletne iglice z visokogorskega rastišča med tremi starostnimi razredi najbolj odporne proti UV-B sevanju. Iz rezultatov sicer ne moremo sklepati, v kolikšni meri je k odzivu rastline prispeval posamezni stresni dejavnik, vendar lahko trdimo, da je smreka razmeroma dobro prilagojena na velike jakosti UV-B sevanja in stresne razmere, kakršne vladajo v visokogorju

Pestrost tipov ektomikorize v smrekovem sestoju na Pokljuki

Types of ectomycorrhizae were studied in soil cores from a young regeneration center in an autochthonous Norway spruce stand on Pokljuka (Triglav National Park, 1200 m.a.s.l.). Soil cores of equal volume (274 ml, 0 - 18 cm deep) weretaken from 33 sampling plots. In the samples all the roots were counted and types of ectomycorrhizae briefly characterized. From these data diversity indices (species diversity (d) and Shannon- Weaver index of diversity (H)) were calculated. Interactions among mycorrhizae, light regime and survival of spruce seedlings were studied. Out of about 50,000 root tips approximately 1 %were non-mycorrhizal, 63 % were old unviable mycorrhizae and 36 % were identifiable ectomycorrhizal root tips, forming 27 different types of ectomycorrhizae. Sixteen types of ectomycorrhizae were briefly characterized. The Shannon diversity index for types of ectomycorrhizae was high (3.13) with respect to the above-ground diversity of vegetation (1.7). The direct site factor was shown to be negatively correlated to ~Piceirhiza cornuta. The diffuse site factor was negatively correlated to Cortinarius sp. (obtusus type) and positively correlated to Inocybe sp. The ground vegetation cover waspositively correlated to Piceirhiza gelatinosa and the total vegetation cover to Elaphomyces sp.V majhni vrzeli domnevno avtohtonega smrekovega sestoja na Pokljuki (Triglavski narodni park) smo proučevali tipe ektomikorize na smreki. Vzorce tal smo jemali na 33. zvezdasto razporejenih vzorčnih ploskvicah s sondo prostornine 274 ml iz globine 0-18 cm. Iz vsakega vzorca smo izločili vse koreninice smreke, jih prešteli, ter na kratko opisali prisotni tip ektomikorize. Izračunali smo Indeks bogastva vrst (d) in Shannonov indeks pestrosti (H). Zanimal nas je vpliv ekoloških dejavnikov (svetlobnih razmer, naravnega pomlajevanja, zastiranja vegetacije) na porazdelitev tipov ektomikorize. Od skupno 50.000 korenin smreke je bilo približno 1 % nemikoriznih, 63 % je bilo nedoločljivih, pretežno starih tipov ektomikorize ter 36 % določljivih ektomikoriznih korenin, ki so skupaj tvorile 27 tipov ektomikorize. Predstavljenih je 16 kratkih opisov za do sedaj neopisane tipe ektomikorize. Shannonov indeks pestrosti za tipe ektomikorize (3,13) je visok glede na pestrost vegetacije (1,7). Ugotovili smo negativno korelacijo direktnega sončnega sevanja s tipom ~Piceirhiza cornuta. Difuzno sončno sevanje je v negativni odvisnosti s tipom Cortinarius sp. (obtusus tip) in v pozitivni odvisnosti s tipom Inocybe sp.. Zastiranje pritalne vegetacije je v pozitivni odvisnosti s tipom Piceirhiza gelatinosa, skupno zastiranje vegetacije pa je v pozitivni odvisnosti s tipom Elaphomyces sp

Učinek ultravijoličnega sevanja na smreko (Picea abies (L.) Karst) in posledice za gorski gozdni ekosistem

Norway spruce trees from the subalpine stand are exposed not only to high UV-B radiation but also to a complex of other environmental factors, suchas high photosynthetically active radiation, extreme temperature conditions, deficient water and mineral supply, which might cause stress responses. Current year needles from the subalpine stand exhibited lower photochemical efficiency and total chlorophyll content compared to samples from lower altitudes. The result suggested that young needles were most vulnerable to stress factors, since the protective mechanisms were not fully developed. Current+1 year needles from the subalpine stand exhibited lower ETSvalues and higher total UV-B absorbing compounds, which may be interpreted as most successful protection against UVB radiation of current+1 year needles among the three needle age classes. Despite the obtained results, the effect of a single stress factor on spruce could not be easily drawn out. Still, we may assume that the spruce is quite tolerant to high UV-B radiation and other extreme environmental factors in the mountains.Rastline, ki uspevajo v gorah, so pogosto izpostavljene stresnim razmeram, predvsem povečani jakosti sevanja UV-B, skrajnim temperaturnim razmeram ter pomanjkanju vode in hranil. Odziv smreke na okoljske razmere je kompleksen. Pri enoletnih iglicah v visokogorju smo izmerili manjšo fotokemično učinkovitost in vsebnost klorofilov, kar kaže na občutljivost mladih iglic, kjer zaščitni mehanizmi še niso dokončno razviti. Pri starejših iglicah razlika ni bila več statistično značilna, zato sklepamo, da se poškodbe v drugem in tretjem letu preprečijo ali popravijo. Pri dveletnih iglicah smreke z visokogorskega rastišča je bil dihalni potencial značilno manjši in vsebnostUV-B absorbirajočih snovi značilno večja, kar pojasnjujemo s tem, da so dveletne iglice z visokogorskega rastišča med tremi starostnimi razredi najbolj odporne proti UV-B sevanju. Iz rezultatov sicer ne moremo sklepati, v kolikšni meri je k odzivu rastline prispeval posamezni stresni dejavnik, vendar lahko trdimo, da je smreka razmeroma dobro prilagojena na velike jakosti UV-B sevanja in stresne razmere, kakršne vladajo v visokogorju

<i>Alchemilla monticola</i> Opiz. Functional Traits Respond to Diverse Alpine Environmental Conditions in Karavanke, Slovenia

Alpine plants are exposed to demanding environmental conditions, such as high ultraviolet (UV) and photosynthetic radiation, extreme temperatures, drought, and nutrient deficiencies. Alpine plants adapt and acclimate to harsh conditions, developing several strategies, including biochemical, physiological, and optical responses. However, alpine plants’ survival strategies are hardly researched due to time-consuming and complex experimental conditions, which are supported by scarce studies. Our study focused on the functional traits of the alpine plant Alchemilla monticola Opiz (hairy lady’s mantle) growing at two different altitudes (1500, 2000 m a.s.l.) and two different UV exposures per altitude. Near-ambient (UV) and reduced (UV-) UV radiations were provided by using two sorts of UV absorbing filters; temperatures were monitored hourly. The experimental plots were located at Tegoška Gora, Karavanke, Slovenia. Functional traits: physiological, biochemical, and optical characteristics were recorded three times during the growing season. A. monticola showed high maximum photochemical efficiency at both altitudes throughout the season, which confirms good adaptation and acclimatization of the plant. Furthermore, significantly higher maximum photochemical efficiency at the subalpine altitude coincided with significantly higher UV absorbing compounds (UV AC) contents at the subalpine compared to the montane altitude in August. A. monticola manifested high UV AC contents throughout the season, with significantly increased synthesis of UV AC contents in the subalpine conditions in August and September. The stomatal conductance rate increased with altitude and was correlated mostly to a lower temperature. A. monticola leaves did not transmit any UV spectrum, which corresponded to high total UV AC contents. The leaf transmittance of the photosynthetic spectrum increased at the subalpine altitude, while the transmittance of the green and yellow spectra increased under the reduced UV radiation in the autumn. A. monticola’s high photosynthetic spectrum transmittance at the subalpine altitude in the autumn might therefore be due to subalpine harsh environmental conditions, as well as plant ontogenetical phase

Biodiversity of types of ectomycorrhizae in a norway spruce stands on Pokljuka

Types of ectomycorrhizae were studied in soil cores from a young regeneration center in an autochthonous Norway spruce stand on Pokljuka (Triglav National Park, 1200 m.a.s.l.). Soil cores of equal volume (274 ml, 0 - 18 cm deep) weretaken from 33 sampling plots. In the samples all the roots were counted and types of ectomycorrhizae briefly characterized. From these data diversity indices (species diversity (d) and Shannon- Weaver index of diversity (H)) were calculated. Interactions among mycorrhizae, light regime and survival of spruce seedlings were studied. Out of about 50,000 root tips approximately 1 %were non-mycorrhizal, 63 % were old unviable mycorrhizae and 36 % were identifiable ectomycorrhizal root tips, forming 27 different types of ectomycorrhizae. Sixteen types of ectomycorrhizae were briefly characterized. The Shannon diversity index for types of ectomycorrhizae was high (3.13) with respect to the above-ground diversity of vegetation (1.7). The direct site factor was shown to be negatively correlated to ~Piceirhiza cornuta. The diffuse site factor was negatively correlated to Cortinarius sp. (obtusus type) and positively correlated to Inocybe sp. The ground vegetation cover waspositively correlated to Piceirhiza gelatinosa and the total vegetation cover to Elaphomyces sp

Morphological and biochemical variations in St. John’s wort, Hypericum perforatum L., growing over altitudinal and UV-B radiation gradients

Abstract Background and Purpose: The climate of the Alpine region is marked by a higher proportion of UV radiation which, combinedwith other stresses, plays an important role in determining the differences between highland and lowland plant populations. The study was aimed at identifying the plant habitus as well as selected morphological and biochemical properties that enable optimised growth under given conditions, and at determining the potential of plants to cope with UV-B radiation stress. Material and Method: St. John’s wort, Hypericum perforatum L., thrives in a continuum of habitats from lowlands to highlands. Chlorophylls a and b and UV absorbing compounds (AC) were determined. The height of the plants, internodes and shoots, and the angle of the shoots were measured. Thicknesses of epidermis, palisade and spongy tissues were examined and evaluated by the computer program AnalySIS 3.0 (Soft Imaging System, Münster, Germany). The number of seeds was counted and their weight determined at the end of the growing season. Results and Conclusions: The content of total UV absorbing compounds (AC) in leaves increased with altitude. The average content of total UV AC in plants growing at 1300 m a.s.l. was about 25% higher than at 400 m a.s.l... The content of chlorophyll showed the opposite trend. At high altitudes plants were shorter, due to shorter and reduced numbers of internodes. Reproductive success was much lower in plants growing at high altitudes; they developed fewer flowers (on average 147 at 400 m a.s.l. and 50 at 1700 m a.s.l.) and seeds per plant than those growing in lowlands. The present study indicates that St. John’s wort growing at high altitudes has developed an effective strategy to mitigate the effects of the severe alpine climate