Low nitrogen availability is one of the main limiting factors for plant growth and development, and high doses of N fertilizers are necessary to achieve high yields in agriculture. However, most N is not used by plants and pollutes the environment. This situation can be improved by enhancing the nitrogen use efficiency (NUE) in plants. NUE is a complex trait driven by multiple interactions between genetic and environmental factors, and its improvement requires a fundamental understanding of the key steps in plant N metabolism—uptake, assimilation, and remobilization. This review summarizes two decades of research into bioengineering modification of N metabolism to increase the biomass accumulation and yield in crops. The expression of structural and regulatory genes was most often altered using overexpression strategies, although RNAi and genome editing techniques were also used. Particular attention was paid to woody plants, which have great economic importance, play a crucial role in the ecosystems and have fundamental differences from herbaceous species. The review also considers the issue of unintended effects of transgenic plants with modified N metabolism, e.g., early flowering—a research topic which is currently receiving little attention. The future prospects of improving NUE in crops, essential for the development of sustainable agriculture, using various approaches and in the context of global climate change, are discussed.

The red raspberry is one of the world’s most popular berries. The main direction of its breeding has switched to nutritional quality, and the evaluation of raspberry germplasm for antioxidant content and activity is very important. As berries, raspberry leaves contain valuable bioactive compounds, but the optimal time for their collection is unknown. We evaluated 25 new breeding lines and standard raspberry cultivars for their polyphenolic content and antioxidant capacity. The antioxidant activity of berries correlated better with the content of total phenolics (0.88 and 0.92) and flavonoids (0.76 and 0.88) than with anthocyanins (0.37 and 0.66). Two breeding lines were significantly superior to the standard cultivars and can be used in further breeding. Leaves collected in three phenological phases of the raspberry contained more phenolics (5.4-fold) and flavonoids (4.1-fold) and showed higher antioxidant activities (2.4-fold in FRAP assay, 2.2-fold in ABTS) than berries. The optimal time for harvesting raspberry leaves is the fruit ripening stage, with exceptions for some cultivars. Genetic diversity analysis using microsatellite (SSR) markers from flavonoid biosynthesis genes divided the genotypes into five clusters, generally in agreement with their kinships. The relationship between genetic data based on metabolism-specific SSR markers and the chemical diversity of cultivars was first assessed. The biochemical and genetic results show a strong correlation (0.78). This study is useful for further the improvement of raspberry and other berry crops.

Pedunculate oak (Quercus robur L.) is widely distributed across Europe and serves critical ecological, economic, and recreational functions. Investigating its responses to stressors such as drought, extreme temperatures, pests, and pathogens provides valuable insights into its capacity to adapt to climate change. Genetic and dendrochronological studies offer complementary perspectives on this adaptability. Tree-ring analysis (dendrochronology) reveals how Q. robur has historically responded to environmental stressors, linking growth patterns to specific conditions such as drought or temperature extremes. By examining tree-ring width, density, and dynamics, researchers can identify periods of growth suppression or enhancement and predict forest responses to future climatic events. Genetic studies further complement this by uncovering adaptive genetic diversity and inheritance patterns. Identifying genetic markers associated with stress tolerance enables forest managers to prioritize the conservation of populations with higher adaptive potential. These insights can guide reforestation efforts and support the development of climate-resilient oak populations. By integrating genetic and dendrochronological data, researchers gain a holistic understanding of Q. robur’s mechanisms of resilience. This knowledge is vital for adaptive forest management and sustainable planning in the face of environmental challenges, ultimately helping to ensure the long-term viability of oak populations and their ecosystems. The topics covered in this review are very broad. We tried to include the most relevant, important, and significant studies, but focused mainly on the relatively recent Eastern European studies because they include the most of the species’ area. However, although more than 270 published works have been cited in this review, we have, of course, missed some published studies. We apologize in advance to authors of those relevant works that have not been cited.

This study examined the bioproductivity of two poplar genotypes propagated by single-tree stem cuttings. The experiment compared variants using cuttings of different lengths (10–22 cm) and containers with volumes from 1 to 3 L. It was found that the best growth performance of seedlings in height according to the traditional container technology (70.6 ± 5.5–111.5 ± 5.0 cm) was observed in the intersectional hybrid of poplar ‘E.s.-38’ (genotype 1). The predominance of the genotype factor over the technology of rooting cuttings was established. The fast-growing genotype 1, E.s.-38, had higher productivity and plant height indices, suggesting it as a variety that can allow for the growth of standard planting material in containers in one season. For genotype 1, the length of cuttings was 10–14 cm when the container volume was increased to 3 L, which could increase the number of cuttings from one mother plant by 2–3 times. The revealed correlations between the height of the seedling and the diameter of the increment, as well as the analysis of the proportions of plant organs, showed that biological features of the rooting of stem cuttings depended on the genotype of poplars. The natural type G2 was characterized by the prevalence of root system growth over the growth of other organs; in the case of short cuttings, the proportion of leaves increased in plants to enhance photosynthesis and ensure rhizogenesis.

The article deals with the bioproductivity of 2 poplar genotypes propagated by single-tree stem cuttings. The experiment compared variants using cuttings of different lengths (10-22 cm) and containers with volumes from 1 to 3 litres. The experiment also considered the variant grown using the Pot-in-pot technology. It was found that the best growth performance of seedlings in height according to the traditional container technology (70.6±5.5-111.5±5.0 cm) was observed in the intersectional hybrid of poplar ‘E.s.-38’ (genotype 1). Annual seedlings of black poplar (genotype 2) were inferior in this index (53.7±4.8-68.1±7.8 cm). PiP technology in case of both genotypes showed good results of height gain (genotype 1 - 165±10.3 cm, genotype 2 - 73.3±8.6 cm). The predominance of the factor ‘Genotype’ over the technology of rooting cuttings (selection of the length of the initial material and the volume of the growing container) was established. In terms of total biomass, G1 (54.4 g) on average exceeds G2 (9.9 g) (natural species) (by 5.5 times), which is determined by a reliable difference in height (by 1.74 times), in diameter by 1.7 times. For both genotypes, depending on the cultivation variant, we can distinguish productivity groups based on the total dry weight of plants: high-productive groups: for G1 - 3L18cm; 3L14cm; 2L22cm; PiP, for G2 - PiP; 3L22cm; 3L18cm, low-productive groups: for G1 - 2L10cm; 1L10cm; 1L14cm, for G2 - 3L14cm; 3L10cm; 2L14cm; 2L10cm; 1L14cm; 1L10cm. The fast-growing genotype 1 ʻE.s.-38ʼ has high productivity and plant height indices, which allows it to be recommended as a variety allowing to grow standard planting material in containers in one season. For genotype 1, the length of cuttings can be 10-14 cm when the container volume is increased to 3 litres, which will increase the number of cuttings from one mother plant by 2-3 times. For genotype 1, the use of containers with a volume of 2 or more litres will produce planting material with a height of more than 100 cm and a diameter of 8-10 mm. Planting material of hard-to-cut poplar species and varieties should be grown in containers with the volume of at least 2 litres. The optimum length of cuttings is 22 cm. Application of Pot-in-pot technology will increase the height of containerised seedlings of fast-growing poplar genotypes by 47 %, diameter by 60 %, and in case of hard-to-propagate genotypes it will increase the height by 20 %, diameter by 20.3 %, which agrees with the data of researches obtained in nurseries of different countries.

The dendrochronological parameters of 97 pedunculate oak (Quercus robur L.) trees including 20 plus trees (142-year-old on average) and four half-sib families for four of them were analyzed considering also specifically years of the most severe droughts that were identified using average monthly air temperature and precipitation data. The tree-ring width (TRW) was mostly affected by air temperature that had the largest cross-dating indices (CDI), up to 78% maximum. However, the 32-year Brückner–Egeson–Lockyer cycle (a climatic cycle of approximately 30–40 years that correlates with sunspot activity) was more reflected in the TRW dynamics in plus trees than precipitation and air temperature. A high-frequency of abnormal TRW was clearly observed during drought periods and in the following 2–3 years. Tree radial-growth reduction due to drought stress varied significantly between families. The resistance to drought based on TRW was higher in the maternal plus oak trees than in progeny. Drought resulted in reduced growth during the subsequent year(s); hence, the minimum growth occurred after the actual climate event. Autumn–winter precipitation and weather conditions were of the greatest importance at the onset of active vegetation in April and May. The influence of air temperature on oak growth was the largest in March (r = 0.39, p < 0.05). The strongest positive correlation between precipitation and growth (with r up to 0.38) was observed in May 2023. Plus trees had a high adaptive potential due to the stability of radial growth during drought with high resistance (Rt = 1.29) and resilience (Rs = 1.09) indexes. The offspring of families 1 (Rt = 0.89, Rs = 0.89) and 2 (Rt = 1.04, Rs = 0.87) had similar resistance and resilience, but the recovery indices (Rc) for offspring in families 1, 2 and 3 exceeded the recovery values for plus trees. For offspring in families 3 and 4, the index values were lower. The revealed responses of wood growth of plus trees to climatic parameters estimated as resistance (Rt), resilience (Rs) and recovery (Rc) indexes and similar responses in their progeny can be used in breeding pedunculate oak for wood growth productivity and drought resistance.