Growth Season Research Articles

Exploring the metabolic daylength measurement system: implications for photoperiodic growth.

Photoperiod is an environmental signal that varies predictably across the year. Therefore, the duration of sunlight available for photosynthesis and in turn the ability of plants to accumulate carbon resources also fluctuates across the year. To adapt to these variations in photoperiod, the metabolic daylength measurement (MDLM) system measures the photosynthetic period rather than the absolute photoperiod, translating it into seasonal gene expression changes linked to photoperiodic growth. In this Tansley Insight, we briefly summarize the current understanding of the MDLM system and highlight gaps in our knowledge. Given the system's critical role in seasonal growth, understanding the MDLM system is essential for enhancing plant adaptation to different photoperiods and optimizing agricultural production.

Investigating the association between dry deposition of cesium and different growth stages of aboveground parts of Chinese yam.

Radiocesium released into the atmosphere from accidents at nuclear facilities, can be deposited on the surface of the surrounding crop fields as dry and wet deposits. Radiocesium deposition can occur at any time during the growth season. In this study, we used stable cesium (Cs) to investigate the changes in dry Cs deposits on surfaces of aboveground parts of Chinese yam (Dioscorea polystachya) during different growth stages. Chinese yam seedlings were grown for eight different lengths of time and were then simultaneously exposed to aerosol particles containing stable Cs in an aerosol exposure chamber for 5h. The deposition density of Cs on the aboveground parts of the seedlings decreased from 29 to 72d after transplantation (DAT) and did not change significantly after 72 DAT. The Cs deposition density on the seedlings on different DAT correlated with the leaf area available for the deposition of aerosol Cs particles.

The Impact of Bamboo (Phyllostachys edulis) Expansion on the Water Use Patterns of Broadleaf Trees

The expansion of bamboo (Phyllostachys edulis) affects the growth status of trees in colonized forests, but there has been insufficient research on changes in tree water physiology. In this study, we used stable δ2H, δ18O, and 13C isotope ratios to analyze the water sources and water use efficiency (WUE) of bamboo, deciduous broadleaf trees (Alniphyllum fortunei), and evergreen broadleaf trees (Machilus pauhoi and Castanopsis eyrei) in a bamboo-expended broadleaf forest (BEBF), a bamboo-absent broadleaf forest (BABF), and a bamboo forest (BF). We found that the expansion of bamboo had no significant effect on the water sources and WUE of deciduous broadleaf trees, but altered the water sources of evergreen broadleaf trees. During the growing season, evergreen broadleaf trees decrease their uptake fractions of surface soil water by 7.1% to 9.6% and increased their uptake fractions of middle soil water by 5.8%~9.4%. Conversely, during the non-growing season, they increased their uptake fractions of surface soil water by 11.9% and decreased their uptake fractions of deeper soil water by 5.6%~12.9%. Additionally, after expanding into broadleaf forests, bamboo increased its uptake proportion of surface and shallow soil water by 20.0% and 9.4% during the growing season. Its WUE also improved, increasing by 20.0 μmol/mol and 13.0 μmol/mol during the growing and non-growing seasons, respectively. These results indicate that as bamboo expands into broadleaf forests, it enhances its competitiveness for water resources by changing its water use strategy. Compared to deciduous broadleaf trees, evergreen broadleaf trees exhibit more flexible water use strategies under the conditions of bamboo expansion. Our research reveals, for the first time, how broadleaf trees adjust their water use strategies in response to bamboo expansion, and uncovers the mechanisms behind bamboo expansion into evergreen broadleaf forests from the perspective of water use strategies. This will aid future forest management under the conditions of bamboo expansion.

Typha domingensis (Pers.) Poir. ex Steud. Potential to Restore Contaminated Wetlands in Egypt

AbstractSeveral studies have reported Typha domingensis (Typhaceae) as a heavy metal (HM) hyperaccumulator. This study aims to assess the seasonal variations in the accumulation potential of T. domingensis (TD) for HM in polluted wetlands in Greater Cairo, Egypt. Sampling of fresh wild plants from the TD’s subterranean (Root and stem) and surface components were gathered from different polluted sites distributed in the canal of Ismailia and Nahia drain, as well as from the River Nile as an unpolluted site (control). The findings showed that pollution negatively affected the chemical characteristics of sediment and water. Except for the TD’s leaf area, there were significant seasonal variations in the growth characteristics (density, stem diameter, leaf length, and width, fresh and dry biomass). The subterranean parts stored higher amounts of HM than the aboveground shoots. Manganese (Mn) concentration (413.2 mg kg− 1) was greater in the roots of autumn plants, whereas their shoots recorded the highest Pb (225.8 mg kg− 1). Al, Cd, Cu, Fe, Ni, and Zn concentrations in summer plant roots (1499.9, 74.8,1356.1, 3948.8, 403.8, and 1294.2 mgkg− 1, respectively). The factor of metal bioaccumulation (BF) values, was high in TD plants growing in a polluted Ismailia canal, but translocation factor (TF) values for all measured elements were lower than one, except for Pb. Summer is the best season for TD growth to sequester high HM concentrations. The authors recommended that TD be employed to mitigate HM pollution in wetlands and restore them.

Effects of Different Amounts of Codominant Stem Subordination on the Growth and Aesthetics ofAcer rubrum‘October Glory’

AbstractBackgroundCodominant stems are a common condition of concern on landscape trees. Understanding the impact of varying degrees of stem reduction can assist practitioners in making informed pruning decisions.MethodsTo determine this, a single reduction or removal cut was made on each pair of codominant stems on medium-agedAcer rubrum‘October Glory’ at approximately 25%, 50%, 75%, and 100% of the diameter relative to the basal diameter at the shared union or left as nonpruned controls. Changes in stem diameter ratio, trunk diameter growth, sprout production, wound closure, and aesthetics were documented for 4 years starting in 2020.ResultsStem diameter ratio was significantly reduced in codominant stems pruned to a relative diameter of 50% or 75% after a single growing season. The 75% treatment reduced growth for 2 growing seasons. There were no significant differences in change of stem diameter ratio with any treatment after 3 growing seasons. Larger pruning cuts resulted in the growth of more sprouts and more exposed wood after 3 years. Aesthetics of trees following pruning were acceptable for nonpruned, 25%, and 50% treatments in all years but were rated as not acceptable or moderately acceptable for 75% and 100% treatments after 2 growing seasons. Trees with the 75% treatment became aesthetically acceptable after 3 growing seasons.ConclusionsPruning codominant stems ofA. rubrum‘October Glory’ with a cut that is 50% or 75% the diameter of the basal diameter at the shared union is appropriate at reducing stem diameter ratio, minimizing exposed wood, and maintaining overall aesthetic appearance after 2 to 3 years.

Changes in the Yield Effect of the Preceding Crop in the US Corn Belt Under a Warming Climate.

Crop rotation has been widely used to enhance crop yields and mitigate adverse climate impacts. The existing research predominantly focuses on the impacts of crop rotation under growing season (GS) climates, neglecting the influences of non-GS (NGS) climates on agroecosystems. This oversight limits our understanding of the comprehensive climatic impacts on crop rotation and, consequently, our ability to devise effective adaptation strategies in response to climate warming. In this study, we examine the impacts of both GS and NGS climate conditions on the yield effect of the preceding crop in corn-soybean rotation systems from 1999 to 2018 in the US Midwest. Using causal forest analysis, we estimate that crop rotation increases corn and soybean yields by 0.96 and 0.22 t/ha on average, respectively. We then employ statistical models to indicate that increasing temperatures and rainfall in the NGS reduce corn rotation benefits, while warming GS enhances rotation benefits for soybeans. By 2051-2070, we project that warming climates will reduce corn rotation benefits by 6.74% under Shared Socioeconomic Pathway (SSP) 1-2.6 and 17.18% under SSP 5-8.5. For soybeans, warming climates are expected to increase rotation benefits by 8.36% under SSP 1-2.6 and 13.83% under SSP 5-8.5. Despite these diverse climate impacts on both crops, increasing crop rotation could still improve county-average yields, as neither corn nor soybean was fully rotated. If we project that all continuous corn and continuous soybeans are rotated by 2051-2070, county-average corn yields will increase by 0.265 t/ha under SSP 1-2.6 and 0.164 t/ha under SSP 5-8.5, while county-average soybean yields will gain 0.064 t/ha under SSP 1-2.6 and 0.076 t/ha under SSP 5-8.5. These findings highlight the effectiveness of crop rotation in the face of warming NGS and GS in the future and can help evaluate opportunities for adaptation.

Temporal and spatial dynamics of the non-indigenous bryozoan, Amathia verticillata, and its associated invertebrate community

The widespread non-indigenous bryozoan, Amathia verticillata primarily colonizes in coastal bays and harbors on anthropogenic structures. Although this habitat-forming bryozoan is widely recognized to house a variety of marine invertebrates within its structure, little is known about their spatiotemporal dynamics and their associated invertebrate community in Southern California, USA. Thus, we undertook a comprehensive yearlong study (July 2021-2022) in an urbanized estuary (Mission Bay, San Diego) to quantify A. verticillata percent cover and abiotic conditions at 6 stations with varying environmental conditions. The seasonal and spatial gradients in temperature and salinity within Mission Bay were as expected with seasonal hypersalinity typical of Mediterranean climate regions. The percent cover of A. verticillata was positively correlated with temperature with the highest percent cover found during the warmest periods, and higher average percent cover found in the warmer, eastern parts of Mission Bay. We also collected three replicate A. verticillata colonies to characterize the marine invertebrate community associated with this non-indigenous bryozoan. We identified 25 families, 24 genera, and 19 organisms to species belonging to the taxonomic groups: amphipods, isopods, tanaids, and polychaetes. Furthermore, we identified juvenile stages and ovigerous females living within A. verticillata. None of the identified invertebrate families contributed more than 21 % to the community. The seasonal growth and annual temporal patterns of A. verticillata may prevent competitively dominant species from becoming established within the invertebrate community and allow A. verticillata to harbor a diverse invertebrate community. Sphaeromatidae isopods were the most common family found in the bryozoan colonies, likely reflecting their broad environmental tolerances. Additionally, while some of the invertebrates found within A. verticillata were also non-indigenous species, more work needs to be done to determine if A. verticillata disproportionately supports these species over native species. Collectively, our results imply that A. verticillata functions as a nursery habitat on anthropogenic structures for peracarid crustaceans and polychaetes. Furthermore, A. verticillata assemble analogous communities across their distribution, which may indicate that invasions are homogenizing biota globally.

A multi-year study of acoustic propagation and ambient sound in a Thalassia testudinum seagrass meadow in a shallow sub-tropical lagoona).

Seagrasses provide a multitude of ecosystem services and act as important carbon sinks. However, seagrass habitats are declining globally, and they are among the most threatened ecosystems on earth. For these reasons, long-term and continuous measurements of seagrass parameters are of primary importance for ecosystem health assessment and sustainable management. This paper presents results from both active and passive acoustical methods for ecosystem monitoring in seagrass meadows. From a propagation perspective, gas bodies contained within the seagrass tissue as well as photosynthetic-driven bubble production result in attenuation, dispersion, and scattering of sound that produce increased transmission loss. For the passive approach, the detachment of gas bubbles from the plants is an important component of the ambient soundscape. Examples of both techniques will be presented based on data collected as part of a two-year continuous deployment of an acoustical measurement system operating in a moderately dense seagrass bed dominated by Thalassia testudinum (turtle grass) in Corpus Christi Bay, Texas. The data show annual trends related to the seasonal growth pattern of Thalassia as well as diurnal trends correlated with photosynthetically active radiation.

Liana versus tree seedling responses to spatial and temporal variation in dry season severity

AbstractLianas are key components of tropical forests, particularly at sites with more severe dry seasons. In contrast, trees are more abundant and speciose in wetter areas. The seasonal growth advantage (SGA) hypothesis postulates that such contrasting distributions are produced by higher liana growth relative to trees during seasonal droughts. The SGA has been investigated for larger size classes (e.g., ≥5 cm diameter at 1.3 m, dbh), but rarely for seedlings. Using eight annual censuses of >12,000 seedlings of 483 tree and liana species conducted at eight 1‐ha plots spanning a strong rainfall gradient in central Panama, we evaluated whether liana seedlings had higher growth and/or survival rates than tree seedlings at sites with stronger droughts. We also tested whether an extreme El Niño drought during the study period had a more negative effect on tree compared to liana seedlings. The absolute density of liana seedlings was similar across the rainfall gradient, ranging from 0.32 individuals/m2 (0.20–0.49, 95% credible interval [CI]) at the driest end of the gradient and 0.27 individuals/m2 (0.13–0.51 95% CI) at the wettest end of the gradient. The relative density of liana seedlings compared to tree seedlings was higher at sites with stronger dry seasons (0.27, 0.21–0.33, 95% CI), compared to wetter sites (0.12, 0.04–0.20 95% CI), due to lower tree seedling densities at drier sites. However, liana seedlings did not grow or survive better than tree seedlings in drier sites compared to wetter sites. Tree seedlings were more negatively impacted in terms of mortality by the extreme El Niño drought than liana seedlings, with an increase in annual mortality rate of 0.013 (0.003–0.025 95% CI) compared to lianas of −0.009 (−0.028 to 0.008 95% CI), but not growth. Our results indicate that lianas do not have a SGA over trees at the seedling stage. Instead, higher survival of liana versus tree seedlings during severe droughts or differences in liana versus tree fecundity or germination across the rainfall gradient likely explain why liana seedlings have higher relative densities at drier sites.

Изучение Iris domestica Goldblatt & Mabb. в условиях Амурской области

The natural range of Iris domestica covers Southeast and East Asia; enters Russia only in the extreme south-west of Primorsky Krai. The primary study of crop began in 2013. Over the past period, I. domestica has established itself as a very winter-hardy plant in the southern and central agricultural zones of the region. The beginning of regrowth in the south falls on 24.03-14.04, in the central zone usually 4-10 days later. The end of the growing season occurs earlier in the central zone, usually in early Octo-ber. The flowering period in the southern zone lasts from the second decade of July to the first or second decade of August and is 40 ± 5 days, in the central zone – from the third ten-day period of July to the third ten-day period of August and is 35 ± 5 days. An assessment of the morphological features of I. domestica showed that larger plants are formed under the conditions of the south. The plants are 6-15 cm higher, the leaf blades are 3-4 cm longer and 0.3-0.5 cm wider, the diame-ter of the flower is 1-1.5 cm larger. The plant is very decorative throughout the growing season. Keywords: IRIS DOMESTICA GOLDBLATT & MABB., GROWING SEASON, DEVELOPMENT PHASES, MORPHOLOGICAL FEATURES

Variance investigation on the microstructural characteristics of vessels among three lignocellulosic biomasses

Especially, the processing and utilization of biomass-based material is closely related to the vessel, e.g. the flow of vapour and additive. It is conventional that vessels in most plants can influence on water and nutrients transport between adjacent cells, which could just infer to be important in the wood-based panel industries. In this work, a complete characterization of vessels and pits is presented for three conventional biomasses in wood-based panel: poplar (Populus deltoides) (P), moso bamboo (Phyllostachys edulis) (B), and the fruit shell of oil camellia (Camellia Oleifera) (FS_OC). Every material is analyzed by combining several techniques including: light microscopy, scanning electron microscopy and surveying calculations from resin casting. The results show that among the three biomass materials, B has a significantly larger vessel width (164.8 ± 6.0 μm for B, 2.2 ± 6.2 μm for P, 10.0 ± 0.8 μm for FS_OC) and smaller inclination angle of the perforation plates (6.8° for B, 44.7° for P), which is more conductive to improving moisture transfer between the vessels. The vessel length of P varies widely from 676.8 μm to 1025.2 μm, which is related to its seasonal growth. By resin casting analysis, more differences in the morphology and distribution of pits in the vessel walls were observed between the three species. Such as, For B, there are numerous pits between vessel cells, while very few to none between vessel and parenchyma cells or fiber. In addition to pits, B and FS_OC also have spiral thickening structures on their vessel walls. The pit membrane is an elliptical shape in P, while slit-like shape in FS_OC and a combination of both elliptical and slit-like shape in bamboo. The unique microstructural characteristics of vessels is related to the individual plant growth traits, which is the basis for biomass-based material processing and utilization.

Improved nitrogen fertilizer management reduces nitrous oxide emissions in a northern Prairie cropland.

Arable croplands are a significant source of nitrous oxide (N2O) emissions, largely due to nitrogen (N) fertilizer applications to support crop production. Nevertheless, there is limited research on the N2O dynamics from canola-wheat rotations in the semi-arid northern Prairies, an important agricultural region. Here, we present micrometeorological N2O fluxes measured from January 2021 to April 2024 in Saskatchewan, Canada, to evaluate the impact of N fertilizer management on the year-round N2O emissions from a canola-wheat rotation. A combination of two 4R (Right Source, Right Rate, Right Time, Right Place) N management practices - a reduced N rate and an enhanced efficiency N fertilizer source - was compared to common fertilizer management practices for the region. Two periods at high risk for N2O flux events were identified, after N fertilizer applications and the following spring thaw, with the magnitude of emissions varying over the multi-year period. As for cumulative emissions, the growing season (GS) N2O emissions were 50 % of annual emissions, presenting an opportunity to mitigate N2O emissions through improved N fertilizer management. Indeed, the improved 4R N management reduced N2O emissions by 57 % over the entire study period without impacting yields. The reduction in GS N2O emissions resulted from the 4R N management lowering mean N2O flux at times of high WFPS (>50 %). The non-growing season (NGS) N2O accounted for 11-67 % of annual emissions. Fall soil nitrate levels were a strong explanatory variable of NGS emissions (r2 = 0.69, r2 = 0.39), but the rate of change and magnitude of NGS emissions depended on thawing conditions - lower for drier thaws, higher for wetter thaws. Ultimately, better N fertilizer management reduces cumulative N2O emissions from cropping systems when practiced for several years.

Monitoring weekly δ 13С variations along the cambium-xylem continuum in the Canadian eastern boreal forest.

Intra-annual variations of carbon stable isotope ratios (δ13C) in different tree compartments could represent valuable indicators of plant carbon source-sink dynamics, at weekly time scale. Despite this significance, the absence of a methodological framework for tracking δ13C values in tree rings persists due to the complexity of tree ring development. To fulfill this knowledge gap, we developed a method to monitor weekly variability of δ13C in the cambium-xylem continuum of black spruce species [Picea mariana (Mill.) BSP.] during the growing season. We collected and isolated the weekly incremental growth of the cambial region and the developing tree ring from five mature spruce trees over three consecutive growing seasons (2019-2021) in Simoncouche and two growing seasons (2020-2021) in Bernatchez, both located in the boreal forest of Quebec, Canada. Our method allowed for the creation of intra-annual δ13C series for both the growing cambium (δ13Ccam) and developing xylem cellulose (δ13Cxc) in these two sites. Strong positive correlations were observed between δ13Ccam and δ13Cxc series in almost all study years. These findings suggest that a constant supply of fresh assimilates to the cambium-xylem continuum may be the dominant process feeding secondary growth in the two study sites. On the other hand, rates of carbon isotopic fractionation appeared to be poorly affected by climate variability, at an inter- weekly time scale. Hence, increasing δ13Ccam and δ13Cxc trends highlighted here possibly indicate shifts in carbon allocation strategies, likely fostering frost resistance and reducing water uptake in the late growth season. Additionally, these trends may be related to the black spruce trees' responses to the seasonal decrease in photosynthetically active radiation. Our findings provide new insights into the seasonal carbon dynamics and growth constraints of black spruce in boreal forest ecosystems, offering a novel methodological approach for studying carbon allocation at fine temporal scales.

Drivers of growth and decay of Sargassum in the Tropical Atlantic: A Lagrangian approach

The proliferation of Sargassum in the Tropical Atlantic has occurred almost every year since 2011, but a strong variability of biomass is observed among years. Essential knowledge about the drivers of Sargassum growth and decay is still lacking to explain this interannual variability. Benefiting from accurate basin scale Sargassum detections provided by remote sensing, and from physical and biogeochemical ocean simulations, we developed a Lagrangian drift-growth model to simulate Sargassum distribution over the period 2016–2020. The resulting trajectories and biomass time series of Sargassum aggregates were analyzed to highlight the main limiting factors of growth and decay. The nitrogen and phosphorous concentrations are found to be weakly restrictive compared to physical limiting factors, especially the temperature. In particular, the warm waters found off northern Brazil appear to be instrumental in triggering the end of seasonal growth of Sargassum. The timing of the seasonal warming of this region strongly impacts the quantities of Sargassum simulated each year. This suggests that this region should be monitored to anticipate the development of Sargassum and resulting strandings.

Drying out fish ponds, for an entire growth season, as an agroecological practice: maintaining primary producers for fish production and biodiversity conservation.

Agroecology largely focusses on terrestrial agroecosystems, but it can also be applied to fish farming. Indeed, ponds are typically used for fish production in Europe, but are also important reservoirs of biodiversity. Numerous studies demonstrate that both fish production and biodiversity are strongly determined by human management. One key practice in extensive fish farming, although more rare in Europe, is to dry out ponds. They are left dry for a complete year after several years of fish production. However, the extent to which this practice affects the functioning of the ecosystem, its biodiversity and fish production remain unclear. We investigated data from 85 fish ponds in the Dombes region, France, sampled between 2007 and 2014. We related variation in key abiotic characteristics to the time since last dry out. The dataset included organic matter content in pond sediments and concentrations of inorganic nitrogen and phosphorus in the water column, and biotic components such as macrophytes cover and richness, phytoplankton concentration and richness, macroinvertebrates density, and fish yield. Our results show that drying out facilitates the mineralization of organic matter in sediments and results in higher concentrations of inorganic nitrogen in the water column. Macrophytes cover is highest during the first year after drying out, and gradually declines after at the expense of increasing phytoplankton concentration. The diversity of both is highest in the first year after drying out and declines rapidly, especially for macrophytes. Fish yield is at its maximum in the second year. Drying out fish ponds appears to be an important agroecological practice in extensive fish farming with an application every three to four years. By nutrient recycling, this practice has a positive impact on the balance between primary producers and indirectly on the whole food web during two years. It optimizes fish production and allows biodiversity conservation.

Inter- and intra-annual carbon isotope fluctuations in Pinus sylvestris L. tree rings whole wood and cellulose in north-eastern Lithuania

In temperate regions trees typically exhibit growth sensitivity to climatic conditions during the growth season. Annual tree ring growth increments correlate with a variety of environmental factors. As an index of water use efficiency, δ13C is a preferred proxy to allow accurate interpretation of environmental factors critical for the tree growth, including changes in climate patterns, variation in the ambient temperature and precipitation. We assumed that isotopic differences within individual tree rings are likely to produce seasonal isotope fluctuations in the chronology that might be interpreted as response to environmental impacts. To verify the assumption, we measured δ13C in annual tree rings of Pinus Sylvestris L. split into 13 intra-annual segments each and checked δ13C correlations with temperature, precipitation, the number of sunshine hours and relative air humidity. For the investigation, we chose a site in north-eastern Lithuania, Zarasai, located in boreal latitude and remote from industrial pollution sources. The methodology of the research was based on high coherence of δ13C chronologies measured in the whole wood and α-cellulose extracted by means of two different methods. The experiment produced strong δ13C correlations with hydrometeorological parameters, especially in the earlywood formed in June

Survey on the occurrence of Aspergillus section Nigri species in grapes cultivated in Umbria (central Italy) and influence of several factors on their distribution

AbstractSecondary bunch rots caused by Aspergillus species belonging to the section Nigri, commonly called black aspergilli, pose a serious threat to grapes yield and quality. Due to their ability to produce ochratoxin A (OTA), they are considered the primary source of contamination of this mycotoxin in grapes. In this study, a three-year survey was realized to assess the occurrence of black aspergilli in grapes harvested in the Umbria region, a very important grapevine cultivation area in central Italy, by fungal isolation and phylogenetic analysis. In addition, the influence of growing season, vineyard location, farming system and grapes growth stages on black aspergilli distribution was examined. Phylogenetic analysis of the 208 obtained isolates showed the presence of three black aspergilli species: Aspergillus tubingensis, Aspergillus welwitschiae and Aspergillus uvarum. Interestingly, A. carbonarius, one of the most important OTA producers, was not detected in the surveyed years. A. tubingensis, whose ability to produce OTA is controversial, was always the most isolated species followed by A. welwistichiae (OTA producer). The species A. uvarum (unable to produce OTA) was detected only in one surveyed year with a low incidence. A. tubingensis was always the species with the highest incidence, regardless of location, and farming system. Growth stage appeared to influence the incidence of the three species, that, in the case of A tubingensis, was lower during setting in comparison to berries pea-size and berries harvest-ripe. Finally, in the setting and berries pea-size stages, a stereomicroscope analysis, showed that flower debris was the substrate from which black aspergilli mainly developed prior to colonizing berries and bunches.

Arctic amplification causes earlier onset of seasonal tree growth in northeastern Siberia

Abstract Although recent warming affects the high-northern latitudes at an unprecedented rate, little is known about its impact on boreal forests because in situ observations from remote ecosystems in Siberia are sparse. Here, we analyze the radial growth and climate sensitivity of 54 Cajander larches (Larix cajanderi Mayr.) from three sites across the northern treeline ecotone within the Omoloy river basin in northeastern Siberia. Three independent tree-ring width chronologies span 279–499 years and exhibit distinct summer temperature signals. These records further reveal evidence for sufficiently earlier onsets of growing seasons since the middle of the 20th century. This phenological shift coincides with rapidly increasing May temperatures and associated earlier snowmelt. Our findings reinforce the importance of high-precision ground measurements from remote regions in Siberia to better understand how warming-induced changes in the functioning and productivity of the boreal forest influence carbon, nutrient, and water cycle dynamics.

Characterization of key aroma compounds of tomato quality under enriched CO2 coupled with water and nitrogen based on E-nose and GC–MS

To investigate the impact of CO2 enrichment coupled with water and nitrogen on the formation of key aroma compounds in tomato quality, researchers characterized tomatoes from two consecutive seasons using electronic nose and gas chromatography-mass spectrometry techniques. The E-nose technique indicated W3C, W1C, W5C, W3S, and W6S being the main sensors distinguishing growth seasons. GC–MS technique identified 51 and 49 typical compounds in spring and autumn, respectively. In spring,1-Octen-3-ol and Benzyl alcohol were mainly affected by CO2, followed by I. In autumn, Hexyl alcohol, Leaf alcohol, (E)-2-Hexen-1-ol and 1-Heptanol are mainly affected by I, followed by N. Cluster analysis identified 28 different tomato aroma substances mainly in floral, grassy, and sweet compounds. Phenylethanol, β-ionone, and (E,E)-2,4-nonadienal had odor activity values exceeding 100 in both seasons. The combined application of 80 % N and 50 % ET at enriched CO2 increased the levels of characteristic volatile organic compounds in tomato.

Changes in Vegetation Greenness and Responses to Land Use Changes in the Yongding River Basin (in North China) from 2002 to 2022

Vegetation is an important component of an ecosystem, fulfilling various ecological functions in areas such as soil and water conservation, climate regulation, and water source maintenance. This study focuses on the Yongding River Basin as a research area. This study used vegetation indices with long time series as a data source in combination with Landsat land use data. This study applied linear trend estimation to analyze the interannual variation trend in vegetation greenness from 2002 to 2022 in the Yongding River Basin and quantitatively analyzed the impact of land use changes on vegetation greenness. The results show that, from 2002 to 2022, the vegetation greenness in the Yongding River Basin has shown an overall increasing trend. The average growth season and the maximum annual normalized difference vegetation index (NDVI) growth rates were 0.006/10a and 0.008/10a, respectively, and the area of increased vegetation greenness accounted for 90% of the total area. During the main growth season (April to October) in the Yongding River Basin, the NDVI generally showed a spatial pattern of being higher in mountainous areas and lower in water areas, with the largest coefficient of variation in vegetation in the river water areas, and the most stable vegetation in forest land. In terms of the changes in vegetation greenness, the contribution rate of arable land was between 36.73% and 38.63%, followed by grassland and forest land, with contribution rates of 26.86% to 27.11% and 23.94% to 26.43%, respectively. The total contribution rate of water areas, construction land, and unused land was around 10.18%. This study can provide a theoretical basis for environmental protection and rational land use in the Yongding River Basin.