Iskanje po repozitoriju

A+ | A- | | SLO | ENG

Povzetek: Drought stress induces pronounced metabolic and transcriptional reprogramming of glucosinolate (GLS) biosynthesis in Brassica oleracea. An integrative approach combining HPLC-based quantification of individual GLSs, quantitative real-time PCR of core biosynthetic and regulatory genes, correlation-based network analysis, and in silico promoter characterization was applied to evaluate drought responses across genetically diverse accessions. Drought triggered strong, accession-specific shifts in GLS composition, with sinigrin content increasing from 35.9% to 55.1% in BR1 and glucoerucin reaching up to 80.2% in CCP1, while indolic GLSs such as glucobrassicin and neoglucobrassicin accounted for >75% of total GLSs in CV2 and CCP3. Hierarchical clustering separated accessions into four distinct drought response clusters independent of morphotype. Correlation analysis revealed drought-induced rewiring of GLS interdependencies, characterized by strengthened positive associations among aliphatic GLSs (r > 0.75). Gene expression profiling identified conserved MYB-centered regulatory modules (MYB28, MYB29, MYB34, MYB122) alongside strong accession-specific induction of CYP79F1 (up to 6.3-fold), FMOGS-OX5 (up to 4.8-fold), and ST5a (up to 5.1-fold). Promoter analysis revealed enrichment of ABA- and stress-responsive cis-regulatory elements. These findings delineate a genotype-dependent regulatory framework underlying GLS plasticity and identify quantitative metabolic and transcriptional markers relevant for breeding drought-resilient Brassica cultivars.
Ključne besede: glucosinolate, gene expression, qRT-PCR, abiotic stress response, drought stress
Objavljeno v DiRROS: 10.02.2026; Ogledov: 752; Prenosov: 326
Celotno besedilo (2,15 MB)
Gradivo ima več datotek! Več...

Povzetek: Common buckwheat and Tartary buckwheat are pseudocereals and grow worldwide. Due to the high concentration of flavonoids, buckwheats are potential sources of smart food. Tartary and common buckwheat are traditionally grown in mountain regions of China, Korea, the northern parts of India, Bhutan, and Nepal. Plants that grow in high elevations are exposed to intense UV radiation, which can harm susceptible sites in the plants. Plants defend themselves against intense radiation by synthesising UV-absorbing compounds. Drought will probably become more frequent and intense due to climate change. UV radiation and drought are environmental parameters that present stress to the plants. These impacts can be synergistic or antagonistic. Selenium (Se) and silicon (Si) can protect plants exposed to UV radiation or drought since Se acts as an antioxidant. Silicon is an abundant element in Earth’s crust. It is present as a liquid or an amorphous or crystalline solid phase in the soil. Selenium and silicon are not essential elements for vascular plants, but they may positively affect plants. Thus, they can be added to the growth media to improve crop yield and quality, enhance resistance to  biotic and biotic stress and improve plant growth.
Ključne besede: common buckwheat, Tartary buckwheat, elements, UV radiations, drought
Objavljeno v DiRROS: 07.01.2026; Ogledov: 578; Prenosov: 391
Celotno besedilo (285,65 KB)
Gradivo ima več datotek! Več...

Povzetek: Introduction: Assessing wood growth phenology over multiple years is essential for understanding the environmental drivers of forest growth and improving large-scale predictions of the carbon cycle. Xylogenesis methods facilitate the assessment of the timing and rate of xylem cell wall thickening, the primary sink of carbon in wood. In angiosperm trees, where wood anatomy is complex, significantly less is known about the factors controlling growth cessation in autumn due to indirect, sinteracting, and lag effects, in contrast to growth resumption in spring. Furthermore, both branch and stem growth must be considered to account for the total aboveground phenology. Methods: In this study, we focused on European beech (Fagus sylvatica) and silver birch (Betula pendula) in a mild temperate region (Northern Belgium). We examined the progress of cell wall thickening in autumn and the seasonal timing of xylem growth cessation for these species’ stems over five years and for their branches over one year in mature trees. In addition, we investigated the same variables in the stems and branches of potted saplings for two years and for oak (Quercus robur) and aspen (Populus tremula) saplings over one year. Results: Our results demonstrate a considerable variation in the progression and cessation of wood growth, with differences of up to a month and a half in growth cessation (early September to late October), predominantly driven by climatic variables. Early cessation of xylem growth in stems was strongly associated with high temperatures in April and August, elevated vapour pressure deficit, and severe soil drought in August. The progression of cell wall thickening in late summer was generally synchronized between branches and stems for every species. However, branches sustained a higher percentage of growth (approximately 2 weeks) in early autumn during non-drought years. Discussion: These findings provide valuable insights for refining models of forest growth and carbon storage, enabling a more comprehensive representation that encompasses the entire tree under different climatic scenarios.
Ključne besede: phenology, cambium, cell wall thickening, hardwood species, atmospheric drought
Objavljeno v DiRROS: 08.09.2025; Ogledov: 710; Prenosov: 454
Celotno besedilo (2,51 MB)
Gradivo ima več datotek! Več...

Povzetek: European beech Fagus sylvatica and Sessile oak Quercus petraea are reaching the north-eastern limits of their natural ranges in northern Poland. According to the projected changes in potential ranges in this region, climatic conditions for both species until 2080 will remain stable. On the other hand, a decrease in the vitality of mature trees and a reduction in their radial growth are currently observed. To understand these contradictory findings, we monitored the cambial activity in both species during two vegetation seasons. 2015 was characterized by a negative water balance, while 2017 was wet. This provided an opportunity to compare how the xylogenesis proceeds in diffuse-porous beech and ring-porous oak during contrasting in the summer precipitation seasons. The forming annual increments were sampled with Presler borer at variable time intervals depending on the leaf phenological phases. The cores were prepared using a sledge microtome and double-stained with safranin and astra blue. Observations of the phases of wood formation and measurements of the width of the forming increments were analysed on the microslide digital images. Differences in the dates of the phenological phases were analysed using Two-Way ANOVA, while the dynamics of the formation of annual increments were fitted to the Single and Double Gompertz function for beech and oak, respectively. The beginning of vessel formation started earlier in both seasons compared to previous studies. Inter-seasonal differences in the duration of spring phenological phases were insignificant for both species, while inter-species differences were significant due to physiological diversity between diffuse-porous beech and ring-porous oak. In dry 2015, cambial activity ceased sooner in both species than in 2017. Differences between oak and beech were insignificant in both years, but statistically significant disparities existed within each species due to varying in precipitation seasons. Rainfall significantly elongated the duration of cambial activity and caused wider tree-rings. According to our study, despite predicted maintaining their climatic niche, both species, situated at the north-eastern cooler range boundary, are expected to produce wood at a lower rate due to the projected warmer central European climate with increased heatwaves and summer droughts.
Ključne besede: climate change, meteorological extremes, wood formation, summer drought, xylogenesis
Objavljeno v DiRROS: 08.07.2025; Ogledov: 768; Prenosov: 747
Celotno besedilo (2,56 MB)
Gradivo ima več datotek! Več...

Povzetek: Climate change is modifying precipitation distribution and increasing drought events frequency, leading to decline in many stands. Pinus nigra was introduced to Poland in the 19th century as a measure to mitigate negative effects of soil pollution. This species is also known to be well adapted to drought conditions. However, its response to drought on different soil conditions remains unclear. The aim is to investigate the growth relation of P. nigra to drought and its resilience under the same climatic conditions but different soil types (fertile and poor soils) in central Poland. Two mature stands of P. nigra were selected, one on fertile soil and one on poor soil. Tree-ring data were collected and analysed to assess growth pat­terns and climate sensitivity. Resilience indices were calculated for seven common drought years, i.e. 1940, 1954, 1963, 1976, 2003, 2006 and 2015, to compare the impact of soil conditions on drought response. The study found similar climate-growth correlations for both soil types, with March temperatures and summer precipitation positively affecting growth, highlighting the significant influence of local climatic conditions on growth. However, resilience to drought varied between poor and fertile soil, with opposite trends ob­served in the drought year 1976 (characterized by dry June, wet July and dry August) and in the drought years 1963 and 2006 (characterized by wet June and dry July and August). With a higher resilience for the trees on poor soil in 1976 and a higher resilience on fertile soil in 1963 and 2006. Moreover, differences were not consistently observed: only 3 of the 7 years were significantly different. The study indicates that soil conditions partially influence the resilience of P. nigra to drought, but the relationship seems drought episode-dependent. Relationships between soil fertility and climate-growth dependencies are complex, and to draw more robust conclusions, further studies are needed, incorporating additional soil types.
Ključne besede: resilience, drought, water capacity, fertility, Poland
Objavljeno v DiRROS: 21.03.2025; Ogledov: 1008; Prenosov: 683
Celotno besedilo (1,15 MB)
Gradivo ima več datotek! Več...