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In an effort to mitigate the environmental impact of chemical fertilizers, plant growth-promoting rhizobacteria (PGPR) have emerged as a more sustainable alternative. Streptomyces saraceticus 31 ('SS31'), a new strain of biocontrol bacteria, was inoculated into rhizosphere soils of 'Benifuji' grape to evaluate its impact on grape roots and berries. The results indicated significant improvements in soil fertility, with higher levels of organic matter, phosphorus, potassium, and nitrate nitrogen compared with those of the controls. Moreover, 'SS31' application elicited a notable reduction in soil pH levels, along with a substantial augmentation in the enzymatic activities of both phosphatase and invertase. The grapes treated with 'SS31' exhibited a notable increase in the number, length, surface area, and volume of fine roots in both 0- to 10-cm and 10- to 20-cm soil profiles. The application of 'SS31' resulted in the observation of greater diameter, lower density, and larger lumen area, along with increased specific hydraulic conductivity in the vessels of roots with 1- to 2-mm diameters. Despite a slight reduction in berry weight compared with that of the controls, 'Benifuji' grape berries displayed higher total soluble solids and lower total titratable acidity after 'SS31' application. Furthermore, 'SS31' treatment elevated the levels of volatile compounds in berries, especially fatty acid-derived compounds. A network analysis revealed a robust positive correlation between the observed improvements in grape berry quality and the morphology as well as the hydraulic conductivity of the grape fine roots. In conclusion, these findings suggest that 'SS31' has the potential to enhance grape root function by expanding the root absorption area and facilitating water transportation. This, in turn, may improve the flavor and aroma of 'Benifuji' grape berries. [ABSTRACT FROM AUTHOR]

Key message: Complex detailed analysis—3D extension of tension wood, Anatomical intensity and tree-ring eccentricity—of one Fagus sylvatica L. individual provides unique insight into tree growth response to landsliding Compression wood formation and tree ring eccentricity of coniferous trees have often been used to date past geomorphic events because of their well-defined tree ring boundaries and visible reaction wood. On the other hand, complex analysis of the ability of tree rings and anatomy of broadleaved trees to detect past geomorphic events is rather rare. Although analysis of broadleaved trees has some limitations, a combination of both approaches (tree ring anatomy and eccentricity) can provide a suitable dendrogeomorphological tool for dating and understanding past landslide events. From an example of a young Fagus sylvatica L. individual, vertical variability of growth responses in the whole stem was detected. The sampled individual was tilted as a direct response to a landslide event caused by intense rainfall in July 1997. It was found that the growth responses of the sampled individual varied with increasing height. By analysing 14 cross sections in the tree stem, it was detected that the sampled individual started to form tension wood (TW) immediately in 1997. This response was also confirmed by the decrease of the vessel lumen area (VLA). The largest decrease of the VLA was in axes A and D. As a result of TW formation, the sampled individual started to form eccentric tree rings. It was observed that with the increasing height of the tree, the number of tree rings with TW and VLA decreased. The formation of TW and eccentricity, but not VLA, also depends on the stem tilting intensity. According to our experimental results, a combination of both approaches can provide a suitable tool to detect the moment of tree growth responses and therefore date landslide movement events. [ABSTRACT FROM AUTHOR]

Background and Aims The increasing frequency of disturbances in temperate forests is responsible for the greater numbers of trees with mechanically damaged cambial zones. Adjustment of wood anatomical structure to balance between safe and efficient water conductivity is one mechanism trees employ to cope with mechanical damage. The relative role of disturbances, tree age and climate in shaping xylem conduits and affecting xylem hydraulic conductivity remains unknown. Methods We performed an experiment with five different mechanical treatments simulating natural disturbances of juvenile Betula pendula trees (stem scarring, tilting, decapitation, root exposure and stem-base burial). After 3 years, trees were cut down, conduit size and density were measured, and specific hydraulic conductivity of each tree ring was calculated. Between-tree and between-year variability in xylem conductivity was decomposed into effects of tree age, climate and disturbances using linear mixed-effects models. Key Results Xylem-specific hydraulic conductivity decreased significantly after treatment in decapitated, tilted and scarred trees. In the last treatment, wood anatomical adjustment was restricted to the area next to the callus tissue zone; in contrast, specific hydraulic conductivity declined over the entire stem circumference after tilting or decapitation. The response of trees with buried stems and exposed roots was generally weak. The overall effect of disturbances on inter-annual variability of wood anatomical structure was greater than the contribution of tree age and climate. Conclusions The results indicate that disturbances are important drivers of xylem hydraulic conductivity. Expected increases in the frequency and intensity of disturbances may alter the theoretical capacity of forest stands for water conductance with a feedback to climate. [ABSTRACT FROM AUTHOR]

Wood ontogeny patterns were determined during the ex vitro acclimatization period in micropropagated plantlets of hybrid poplar clones T-14 [Populus tremula × (Populus × canescens)] and T-50 [(Populus × canescens) × Populus tremula]. The temporal course of developmental changes in the woody tissue was characterized on a weekly basis starting from the day of transfer to the ex vitro environment until full acclimatization was achieved on day 28. In vitro rooted plantlets had already initiated lignification of secondary xylem cells. The greatest increase in the amount of woody tissue was observed on days 21 and 28. At the end of the acclimatization period, T-14 plantlets contained on average 41.4 % of secondary xylem tissue compared to 30.3 % found in T-50 plantlets. During the course of acclimatization, both clones displayed identical patterns of vessel lumen size distribution from small vessel lumen area to large vessel lumen area. This pattern differs from the characteristic diffuse-porous pattern of approximately evensized vessel lumen area distribution typical of mature wood. At the end of acclimatization, the differences in vessel lumen area and relative conductivity between the clones were negligible. Development of secondary xylem tissue during ex vitro acclimatization promotes the establishment of vigorous regenerants with stems that show increased bending strength and stiffness.

Increasing temperatures and recent changes in runoff regimes observed in Central Europe might alter the growth and relative water uptake of floodplain trees. To predict responses of floodplain forests to climate change, it is necessary to determine the climatic controls over tree growth and vessel anatomy. We analysed the responses of tree-ring width and earlywood vessel anatomical parameters (average vessel lumen area, vessel density and total vessel lumen area) of pedunculate oak ( Quercus robur L.) growing in a floodplain to hydroclimatic conditions represented by temperature, the drought index (scPDSI), river discharge, groundwater level, and occurrence of floods and drought events. Site chronologies were assembled for floodplain and reference sites and, subsequently, correlated with time series of hydroclimatic conditions. Our results show that radial growth of floodplain trees is particularly positively influenced by temperature during the growing season and during previous year’s summer. By contrast, the growth of reference trees is highly drought-limited. Earlywood average vessel lumen area chronologies from both floodplain and reference sites share a positive temperature signal from January to April. However, the effect of water availability (indicated by the drought index) on vessel size is mostly negative for floodplain trees (with a maximum response to the autumn of the year preceding tree-ring formation) and positive or non-significant for reference trees. Vessel density chronologies contain the inverse environmental information as tree-ring width, however, with amplified negative correlations with current year temperatures at floodplain sites. Total vessel area is associated mostly with temperature in previous May and June. The drought index recorded exactly the same information in tree-rings as did river discharges and groundwater levels. The results of both correlation and trend analysis evidence that tree-ring width of floodplain Q. robur unambiguously increases with increasing temperature; on the other hand, droughts can become a serious problem affecting the productivity of reference trees growing in more distal parts of the lowland. Vessel size of Q. robur growing outside the floodplain recently tends to increase with increasing temperatures, making xylem more effective at water transport but also more vulnerable to cavitation. [ABSTRACT FROM AUTHOR]

Whole-plant approaches allow quantification of the temporal overlap between primary and secondary growth. If the amount of time available to grow is short, there may be a high temporal overlap between shoot growth and wood formation. We hypothesise that such overlap depends on the duration of the growing season and relates to wood anatomy. We evaluated wood anatomy, shoot longitudinal and radial growth rates, fine root production and the concentrations of non-structural carbohydrates ( NSC) in the wood of six sub-shrub species growing in sites with contrasting climatic conditions ( Lepidium subulatum, Linum suffruticosum, Salvia lavandulifolia, Satureja montana, Ononis fruticosa, Echinospartum horridum). Sub-shrub species living in sites with a short growing season displayed a high overlap between aboveground primary and secondary growth and formed wide vessels, whereas species from the warmest and driest sites presented the reverse characteristics. The highest overlap was linked to a rapid shoot extension and thickening through the enhanced hydraulic conductivity provided by wide vessels. The reductions in NSC concentrations when growth peaked were low or moderate, indicating that sub-shrubs accumulate NSC in excess, as do trees. The temporal overlap among primary and secondary growth in woody plants may be connected to the duration and rates of shoot and wood growth, which in turn depend on the vessel lumen area. [ABSTRACT FROM AUTHOR]

Time series of tree-ring anatomical features are important to understand the functional role of xylem plasticity over the life span of trees, and thus to reconstruct past ecological and climatic conditions. Holm oak ( Quercus ilex L.) is a drought-tolerant tree widely distributed in the Mediterranean Basin. Chronologies of tree-ring width (TRW), vessel lumen area [maximum (MAX) and mean (MVA)] and vessel density (VD) were developed for the period 1942-2001. Each ring was divided into three sections to compare the intra-annual variation of vessel features with the climate conditions during the growing season. The common variability of tree-growth and vessel features was analyzed using a principal component analysis (PCA). Vessel lumen area (MAX and MVA) and TRW loaded positively on the first axis (PC1), whereas VD from the first and second part of the ring (VD1 and VD2) loaded negatively, suggesting that these variables share a common variance. On the other hand, VD in the last third of the ring (VD3) loaded positively on second axis (PC2). PC1 showed a strong positive correlation with precipitation during the hydrological year (prior October-September) and a negative correlation with temperature in spring (April-May), while PC2 showed a negative correlation with precipitation in June. Our results showed that TRW and vessel lumen area were mainly dependent on moisture conditions along the growing season, while vessel density probably plays an important role in the balance between hydraulic conductivity and safety to embolism to better adjust the hydraulic system to water availability. [ABSTRACT FROM AUTHOR]

Wood ontogeny patterns were determined during the ex vitro acclimatization period in micropropagated plantlets of hybrid poplar clones T-14 [ Populus tremula × ( Populus × canescens)] and T-50 [( Populus × canescens) × Populus tremula]. The temporal course of developmental changes in the woody tissue was characterized on a weekly basis starting from the day of transfer to the ex vitro environment until full acclimatization was achieved on day 28. In vitro rooted plantlets had already initiated lignification of secondary xylem cells. The greatest increase in the amount of woody tissue was observed on days 21 and 28. At the end of the acclimatization period, T-14 plantlets contained on average 41.4 % of secondary xylem tissue compared to 30.3 % found in T-50 plantlets. During the course of acclimatization, both clones displayed identical patterns of vessel lumen size distribution from small vessel lumen area to large vessel lumen area. This pattern differs from the characteristic diffuse-porous pattern of approximately evensized vessel lumen area distribution typical of mature wood. At the end of acclimatization, the differences in vessel lumen area and relative conductivity between the clones were negligible. Development of secondary xylem tissue during ex vitro acclimatization promotes the establishment of vigorous regenerants with stems that show increased bending strength and stiffness. [ABSTRACT FROM AUTHOR]

Reaction wood formation, in particular compression wood in conifers, has often been used to date geomorphic events such as debris flows or snow avalanches. However, very little is known yet about the variations of tension wood formation and particularly cross-sectional vessel characteristics in response to different mechanical impacts. To test whether different intensities and characteristic forms of tension wood formation induce the formation of vessels with changing sizes, growth experiments with different treatments were conducted with alder and beech followed by wood anatomical analysis of the vessels. The experiments comprised bending treatments of varying severities in combination with cambium wounding and other alterations. The treatments were successful in inducing different intensities in tension wood expressed by variations of vessel lumen area (VLA). An increasing bending stress resulted in the formation of lower VLA values. When the apex or the root system was damaged or the apex remained vertical, VLA values decreased less and the tension wood formation was regarded as less intense. Our research shows that VLA is affected by mechanical impacts and that the application of wood anatomical techniques can potentially provide supplementary information about type and intensities of past mechanical impacts in angiosperm tree growth. [ABSTRACT FROM AUTHOR]

Knowledge on the ecology of tree species in both their native and introduced range can increase the understanding of their successful establishment and spread outside the native range. Here, we analysed radial growth patterns of Ailanthus altissima (Mill.) Swingle in two sites in its native range in eastern China and in two sites in the introduced range in southern Switzerland, where it started to disperse into forests in the 1950s. Growth rates were similar despite lower amounts of growing season precipitation in China. Furthermore, we found negative correlations between annual radial growth and average temperatures in the growing season at the warmest of the four sites, which suggest that radial growth of A. altissima starts to be limited by average growing season temperatures above 21 °C. Regarding wood anatomy, we did not find clear correlations between vessel lumen area and monthly temperature or precipitation at the time of tissue formation in spring. Overall, our results demonstrate that A. altissima has the potential to grow in drier conditions than currently found in Switzerland, which is in line with previous studies. [ABSTRACT FROM AUTHOR]