Search results for "picea"
showing 10 items of 113 documents
TTAS a New Stilbene Derivative that Induces Apoptosis in Leishmania Infantum
2012
Leishmania parasites are able to undergo apoptosis (programmed cell death), similarly to mammalian cells. Recently it was demonstrated in vitro the anti-leishmanial effect of some natural and synthetic stilbenoids including resveratrol and piceatannol. In this study we evaluated the Leishmanicidal activity of a pool of stilbene derivatives which had previously shown high apoptotic efficacy against neoplastic cells. All the compounds tested were capable to decrease the parasite viability in a dose-dependent manner. Trans-stilbenes proved to be markedly more effective than cis-isomers. This was different from that observed in tumor cells in which cis-stilbenes were more potent cytotoxic agent…
Investigations on the content indole-3-acetic spruce needles of healthy and damaged trees of various sites
1993
Summary Surveys were made on the concentration of indole-3-acetic acid (IAA) in spruce trees of various sites. The concentrations of the hormone were specified with a radioimmunoassay after the needle extract had been purified in several steps. The content of IAA in needles of damaged trees was distinctly lower than the content in needles of healthy trees. Another feature was the annual rythm of the IAA content with the maximum of concentration in June. A distinct diurnal course with highest level of concentration during the early afternoon hours was also observed. The diurnal rhythm of the damaged trees was clearly lower. The supposition is that the lower IAA content is responsible for a p…
Synthetic transformation of hydroxymatairesinol from Norway spruce (Picea abies) to 7-hydroxysecoisolariciresinol, (+)-lariciresinol and (+)-cyclolar…
2003
We have developed a method for the transformation of hydroxymatairesinol to optically pure (+)-lariciresinol and (+)-cyclolariciresinol via the hitherto unreported lignan 7-hydroxysecoisolariciresinol. The two naturally occurring isomers of hydroxymatairesinol were reduced with LiAlH4 to a mixture of two epimers of 7-hydroxysecoisolariciresinol, which were further selectively transformed to (+)-lariciresinol and (+)-cyclolariciresinol by an acid catalysed intramolecular cyclisation reaction. The structure of the major isomer of 7-hydroxysecoisolariciresinol was confirmed by X-ray crystallography and thereby also the absolute configurations of the two isomers of hydroxymatairesinol were unam…
Impact of Trichoderma sp. on the Development of Heterobasidion Annosum in Decayed Understory Picea Abies Stumps
2017
Abstract Heterobasidion annosum (Fr.) Bref. s.l. causes significant economic losses in conifer forests. Therefore, to reduce the spread of the infection surfaces of freshly cut conifer, stumps are commonly treated with biological control agents. Trichoderma sp. shows very strong antagonistic effect against H. annosum in vitro, but relatively few field studies have been conducted. Moreover, most of previous studies examined the impact of Trichoderma sp. on H. annosum in healthy conifer stumps. The aim of our work was to evaluate the effect of Trichoderma sp. against H. annosum in already decayed understory spruce stumps. In total, 75 decayed spruce stumps were surveyed. Part of the spruce st…
Diagnosis of damage to Norway spruce (Picea abies) through biochemical criteria
1995
Bioindication can be carried out at different hierarchical levels, eg. cell, organism, and ecosystem. While the monitoring of damage by visible criteria (e.g. loss of needles) is connected with the organism as a whole, the monitoring of damage by biochemical indicators is above all connected with cell metabolism. The degree of vitality of a tree can be ascertained through the integration of a number of biochemical parameters. Furthermore, a differential diagnosis of a particular stress pattern can be carried out because of the feedback pattern of several biochemical indicators. In order to describe and interpret biochemical or physiological changes that have been caused by a number of facto…
Pacilās vai vagās stādīto priedes (Pinus sylvestris) un egles (Picea abies) stādu agrīnā attīstība āreņos un citi meža atjaunošanas sekmīgumu ietekmē…
2017
Augsnes sagatavošana ir plaši izmantota prakse parastās egles (Picea abies) un parastās priedes (Pinus sylvestris) audžu atjaunošanā. Visplašāk izmantotās augsnes sagatavošanas metodes ir vagu un pacilu izveide, šīs metodes uzlabo stādu augšanu un palielina izdzīvojušo stādu skaitu salīdzinājumā ar neapstrādātu augsni. Neskatoties uz šo augsnes sagatavošanas veidu plašo pielietojumu mežu atjaunošanā Latvijā, līdz šim nebija veikti pētījumi, kas salīdzinātu vagu un pacilu sekmību āreņu tipa mežos. Pētījums tika veikts 2016. gadā, periodā no jūlija beigām līdz augusta beigām. Apsekotās audzes bija atjaunotas pirms viena līdz trīs gadiem. Mērķis bija noskaidrot, kurš no apstrādes veidiem snieg…
Uniform climate sensitivity in tree-ring stable isotopes across species and sites in a mid-latitude temperate forest.
2014
Tree-ring stable isotopes, providing insight into drought-induced eco-physiological mechanisms, are frequently used to reconstruct past changes in growing season temperature and precipitation. Their climatic response is, however, still not fully understood, particularly for data originating from non-extreme, mid-latitude environments with differing ecological conditions. Here, we assess the response of δ(13)C, δ(18)O and tree-ring width (TRW) from a temperate mountain forest in the Austrian pre-Alps to climate and specific drought events. Variations in stem growth and isotopic composition of Norway spruce, common beech and European larch from dry, medium and moist sites are compared with re…
Celmeņu Armillaria spp. dzīvotspēja un patogenitāte Latvijas izcelsmes priežu Pinus sylvestris un egļu Picea abies stādos
2017
Celmeņu Armillaria spp. ģints sēņu izraisītā sakņu trupe ir iemesls ievērojamiem mežsaimnieciskajiem zaudējumiem. Darbā analizēta Armillaria solidipes, A. cepistipes un A. borealis dzīvotspēja, izplatīšanās potenciāls un patogenitāte 5-6 gadus vecos parasto priežu (563 gab.) un parasto egļu (350 gab.) stādos. Armillaria spp. inokulātu attīstība novērota stādu audzēšanai paredzētajā kūdras substrātā. Novērojumus priežu un egļu stādiem veica pēc attiecīgi 12 un 15 mēnešiem. Patogēna dzīvotspēja bija atkarīga no tā sugas: A. cepistipes būtiski augstāka, bet A. solidipes viszemākā. Augstāko izplatīšanās potenciālu konstatēja A. cepistipes, bet viszemāko A. solidipes. Visas trīs Armillaria sugas…
Celmeņu Armillaria spp. sastopamība parastās egles Picea abies audzēs kūdreņos
2022
Darbs izstrādāts Latvijas Valsts mežzinātnes institūta „Silava” Fitopatoloģijas un mikoloģijas laboratorijā un Ģenētisko resursu centrā. Pētījums veikts akciju sabiedrības „Latvijas valsts meži” un Latvijas valsts mežzinātnes institūta „Silava” zinātņietilpīgā līgumdarba „Sakņu trupes bojājumu risku mazināšana un tās ietekmes izpēte” ietvaros. Pētījumā analizēta celmeņu Armillaria spp. sastopamība ar Heterobasidion spp. inficētās parastās egles Picea abies audzēs ar nosusinātām kūdras augsnēm. Rizomorfu paraugi ievākti piecos parauglaukumos Meža pētīšanas stacijas „Kalsnava” teritorijā. Izmantojot programmu Win RHIZO 2005 C, analizēti rizomorfu morfoloģiskie rādītāji. Armillaria spp. sugu n…
Phlebiopsis gigantea attīstība maza diametra skuju koku celmos
2016
Lai novērtētu P. gigantea micēlija attīstību skuju koku celmos sastāva kopšanas cirtēs, četrās audzēs Vidusdaugavas mežsaimniecībā tika ierīkots eksperiments, kurā ar „Rotstop” un divu Latvijas P. gigantea izolātu konīdijsporu suspensijām apstrādāja maza diametra (3 – 12 cm) parasto egļu un parasto priežu celmus. Pēc gada tika ievākti koksnes paraugi un analizēta P. gigantea attīstība celmos. P. gigantea izolāti labāk attīstījās maza diametra priežu celmos nekā egļu celmos. Dabiskā P. gigantea infekcija konstatēta 20% maza diametra priežu celmu. Salīdzinot „Rotstop” ar vietējiem izolātiem, Latvijas izolāta PG137 attīstības biežums priežu celmos būtiski neatšķīrās un P. gigantea micēlijs sas…