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Non-structural carbohydrates (NSC) as resource reserves of plants play important roles in energy supply for normal growth and reproduction under environmental stress. The yield of perennial crops is mainly determined by the carbohydrate production and allocation in the current growth season, as well as the re-allocation of NSC reserves. However, the contribution of NSC to crop yield has not been fully determined. Fengdan (Paeonia ostii) is a variety of oil Peony that is newly developed in China. The effects of tree age and NSC on yield were examined by investigated the variations of biomass, soluble sugars, starch, and NSC in the organ and whole tree levels in the dormant and ripening stages of Fengdan populations with 4-, 6-, and 8-year-old in 2020 and 5-, 7-, and 9-year old in 2021. Results showed that the biomass, yield (seed biomass), soluble sugars, starch, and NSC reserve of Fengdan at the whole tree level increased with the increase in age. Although consistent correlations were observed between soluble sugars, starch and NSC storage, and yield among the plants with different ages, Fengdan showed allometric growth relationships between the accumulation of soluble sugars, starch, and NSC and yield and biomass (standardized major axis analyses slope b ≠ 1). Tree age significantly affected biomass and its allocation and NSC levels, especially the yield of Fengdan plants. The results of the investigation of the variations in the relationships between the yield and seasonal fluctuations of NSC and biomass indicate that roots is the key storage structure, whereas stems both serve as sink and/or source functions for the adult (7-9a) plants. NSC level, particularly the concentration of soluble sugars, in stems mainly influences Fengdan yield. These findings together provide new insights into the mechanisms underlying the yield formation of Fengdan and have implications for manipulating sink-source relationship to achieve high yield. [ABSTRACT FROM AUTHOR]

Simple Summary: Plants adapt themselves to harsh environmental conditions by changing morphological parameters through phenotypic plasticity. Plants modify their functional traits and allocate biomass to either tolerate or resist the stress caused by their variable habitats. In this study, we observed that Aeluropus lagopoides, being among the few halophytic palatable species of salt marshes, adapt to the harsh salt marshes of different eco-regions by significantly modifying its morphological and physiological traits. Due to this structural modification, this plant showed great potential to rehabilitate different inland and coastal saline flat areas (sabkha), taking saline agriculture and soil remediation into consideration. Understanding the response variation of morphological parameters and biomass allocation of plants in heterogeneous saline environments is helpful in evaluating the internal correlation between plant phenotypic plasticity mechanism and biomass allocation. The plasticity of plants alters the interaction among individuals and their environment and consequently affects the population dynamics and aspects of community and ecosystem functioning. The current study aimed to assess the plasticity of Aeluropus lagopoides traits with variation in saline habitats. Understanding the habitat stress tolerance strategy of A. lagopoides is of great significance since it is one of the highly palatable forage grass in the summer period. Five different saline flat regions (coastal and inland) within Saudi Arabia were targeted, and the soil, as well as the morphological and physiological traits of A. lagopoides, were assessed. Comprehensive correlation analyses were performed to correlate the traits with soil, region, or among each other. The soil analysis revealed significant variation among the five studied regions for all measured parameters, as well as among the soil layers showing the highest values in the upper layer and decreased with the depth. Significant differences were determined for all tested parameters of the morphological and reproductive traits as well as for the biomass allocation of A. lagopoides, except for the leaf thickness. In the highly saline region, Qaseem, A. lagopoides showed stunted aerial growth, high root/shoot ratio, improved root development, and high biomass allocation. In contrast, the populations growing in the low saline region (Jizan) showed the opposite trend. Under the more stressful condition, like in Qaseem and Salwa, A. lagopoides produce low spikes in biomass and seeds per plant, compared to the lowest saline habitats, such as Jouf. There was no significant difference in physiological parameters except stomatal conductance (gs), which is highest in the Jizan region. In conclusion, the population of A. lagopoides is tolerant of harsh environments through phenotypic plasticity. This could be a candidate species to rehabilitate the saline habitats, considering saline agriculture and saline soil remediation. [ABSTRACT FROM AUTHOR]

In exotic coniferous plantations established in treeless environments, light availability is drastically reduced, limiting the development of the native herb–shrub layer and consequently ecosystem functions and services. However, plants exhibit different responses to deal with changes in the light environment. Aiming to contribute to management guidelines favoring understory vegetation persistence in forest plantations, we evaluated, under nursery trial, the growth of three representative species of the Patagonian steppe at 20, 60, and 100% irradiance. For each species, we compared, among treatments, total biomass, biomass allocation, and specific leaf area several times during two growing seasons, relative growth rate, net assimilation rate, and leaf area ratio at each time interval, and reproductive structures the second growing season. Berberis microphylla and Adesmia volckmannii maintained their total biomass at 60% irradiance, with A. volckmannii showing a tendency to increase it, whereas Poa ligularis tended to decrease total biomass at irradiances below 60%. For the three species, changes in biomass allocation, generally higher leaf mass fraction, and higher specific leaf area were detected at 20% and sometimes at 60% irradiance. Relative growth rate and net assimilation rate, in general, tended to be higher at 60 and 100% irradiance, whereas leaf area ratio was higher at 20% and sometimes at 60% irradiance. Adesmia volckmannii and P. ligularis had fewer reproductive structures at 20% irradiance. These results suggest that the analyzed species present a certain level of shade tolerance, at least up to 60% irradiance, that may benefit their development in forest plantations with appropriate management. [ABSTRACT FROM AUTHOR]

Despite increasing evidence of kin recognition in natural and crop plants, there is a lack of knowledge of kin recognition in herbicide-resistant weeds that are escalating in cropping systems. Here, we identified a penoxsulam-resistant barnyardgrass biotype with the ability for kin recognition from two biotypes of penoxsulam-susceptible barnyardgrass and normal barnyardgrass at different levels of relatedness. When grown with closely related penoxsulam-susceptible barnyardgrass, penoxsulam-resistant barnyardgrass reduced root growth and distribution, lowering belowground competition, and advanced flowering and increased seed production, enhancing reproductive effectiveness. However, such kin recognition responses were not occurred in the presence of distantly related normal barnyardgrass. Root segregation, soil activated carbon amendment, and root exudates incubation indicated chemically-mediated kin recognition among barnyardgrass biotypes. Interestingly, penoxsulam-resistant barnyardgrass significantly reduced a putative signaling (–)-loliolide production in the presence of closely related biotype but increased production when growing with distantly related biotype and more distantly related interspecific allelopathic rice cultivar. Importantly, genetically identical penoxsulam-resistant and -susceptible barnyardgrass biotypes synergistically interact to influence the action of allelopathic rice cultivar. Therefore, kin recognition in plants could also occur at the herbicide-resistant barnyardgrass biotype level, and intraspecific kin recognition may facilitate cooperation between genetically related biotypes to compete with interspecific rice, offering many potential implications and applications in paddy systems. [ABSTRACT FROM AUTHOR]

To better understand the phenotypic plasticity of the highly invasive native weed, Pedicularis kansuensis, we investigated and compared phenotypes (morphology, biomass, and nutrient composition) at different levels of invasion (low: 0 < cover ≤ 30%; medium: 30% < cover ≤ 70%; and high: cover > 70%). With the increase in invasion level, the plasticity of inflorescence length, single-leaf thickness, and specific leaf area increased, while the plasticity of single-leaf area and crown width decreased. During the invasion process, we observed significant density-dependent effects, including changed morphological characteristics, increased total aboveground biomass, and decreased plant height, inflorescence length, root length, crown width, single-leaf area, structure biomass of structures (root, stem, inflorescence), and individual biomass (p < 0.05). During the reproductive period of P. kansuensis, the resource allocation (C, N, and P content, total biomass, biomass allocation) to inflorescence was significantly higher than to root and stem, while the elemental ratios (C:N, C:P, N:P) of inflorescences were significantly lower than those of roots and stems (p < 0.05). When the invasion level increased, the ratio of inflorescence C:N and biomass allocation to roots increased significantly; conversely, inflorescence N and biomass allocation to inflorescences and stems decreased significantly (p < 0.05). This led to a decrease in resource allocation to aboveground parts and more resources allocated to the roots, significantly increasing the root-to-shoot ratio (p < 0.05). Based on the phenotypic differences among different invasion levels, we suggest that P. kansuensis adapted to a competitive environment by regulating morphology, biomass, and nutrient allocation, thereby enhancing the potential of invasion and spread. [ABSTRACT FROM AUTHOR]

Interactions between alien plants and local enemies in introduced ranges may determine plant invasion success. However, little is known about whether herbivory-induced responses are transmitted across vegetative generations of plants and whether epigenetic changes are involved during this process. In a greenhouse experiment, we examined the effects of herbivory by the generalist herbivore Spodoptera litura on the growth, physiology, biomass allocation and DNA methylation level of the invasive plant Alternanthera philoxeroides in the first- (G1), second- (G2) and third-generation (G3). We also tested the effects of root fragments with different branching orders (i.e., the primary- or secondary-root fragments of taproots) of G1 on offspring performance. Our results showed that G1 herbivory promoted the growth of the plants in G2 that sprouted from the secondary-root fragments of G1 but had a neutral or negative effect on the growth of the plants in G2 from the primary-root fragments. The growth of plants in G3 was significantly reduced by G3 herbivory but not affected by G1 herbivory. Plants in G1 exhibited a higher level of DNA methylation when they were damaged by herbivores than when they were not, while neither plants in G2 nor G3 showed herbivory-induced changes in DNA methylation. Overall, the herbivory-induced growth response within one vegetative generation may represent the rapid acclimatization of A. philoxeroides to the unpredictable generalist herbivores in the introduced ranges. Herbivory-induced trans-generational effects may be transient for clonal offspring of A. philoxeroides, which can be influenced by the branching order of taproots, but be less characterized by DNA methylation. [ABSTRACT FROM AUTHOR]

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In order to investigate the effect of Ca on the biomass allocation strategies of tree species with different growth rates under drought conditions, we treated poplar (Populus canadensis cv) cuttings and mulberry (Morus alba) seedlings with two soil moisture levels (40 ± 5% and 80 ± 5% maximum water holding capacity) and two soil Ca levels (0 and 200 mg·kg−1 Ca2+) in a greenhouse experiment, and then measured the Ca uptake, growth, gas exchange parameters, biomass allocation, and leaf traits. Drought induced a reduction in biomass accumulation of poplar cuttings and mulberry seedlings, and the cuttings and seedlings exhibited different biomass allocation patterns in response to drought stress. Under Ca0 treatment, poplar cuttings allocated more biomass to leaves and less biomass to stems under drought conditions, leading to an increased leaf/stem (L/St) ratio and higher SLA than under moist conditions in order to maintain higher Pn, and had enhanced WUE to cope with drought stress. Under the same treatment, mulberry seedlings allocated more biomass to roots and less biomass to stems, leading to an increased root/shoot (R/S) ratio and lower SLA, to improve drought resistance. Ca200 treatment decreased the growth of poplar cuttings and mulberry seedlings, whereas it enhanced the WUE, root growth, and R/S ratio of poplar cuttings and the WUE of mulberry seedlings, and alleviated drought stress in both species. [ABSTRACT FROM AUTHOR]

Nitrogen (N) is one of the limiting nutrients for plant growth and metabolism in terrestrial ecosystems. Numerous studies have explored the effects of N addition on the eco-physiological traits and biomass production of plants, but the underlying mechanism of how N deposition influences biomass allocation patterns remains controversial, especially for urban greening trees. A greenhouse experiment was conducted for 7 months, using two dominant tree species of urban streets in North China, including the coniferous tree species Pinus tabuliformis and the broadleaved tree Fraxinus chinensis, under three levels of N addition: ambient, low N addition, and high N addition (0, 3.5, and 10.5 gN m−2 year−1). The plant growth, biomass distribution, functional traits, and soil nutrient properties of the two trees were determined. Overall, N addition had positive effects on the aboveground and belowground biomass of P. tabuliformis, which also shifted its functional traits to an acquisitive strategy, while F. chinensis only increased root biomass distribution and fast traits as N increased. Furthermore, N supply increased the soil N and phosphorus availability of both trees and improved their root nutrient uptake capacity, resulting in an increase in their root–shoot ratio. Optimal partitioning theory could better explain why trees would invest more resources in roots, changing root structure and nutrient uptake, thus increasing root biomass allocation to adapt to a resource-poor environment. These findings highlight the importance of plant functional traits in driving the responses of biomass allocation to environmental changes for urban greening dominant tree species and could help to come up with new tree growth strategies in silvicultural practice for urban green space.

Tree crown plays a crucial role in the process of photosynthesis and the formation of biomass. The site conditions and stand density have a significant impact on tree and crown growth, as well as biomass formation. Understanding crown growth and its influence on the allometric growth of the biomass of various organs under diverse site conditions and densities is critical to comprehending forest adaptation to climate change and management. This study examined the growth of trees, crown, and biomass in 36 plots of young Platycladus orientalis plantations across three site conditions (S1: thin soil on the sunny slope; S2: thick soil on the sunny slope; S3: thin soil on the shady slope) and four densities (D1: ≤1500 plants/hm2; D2: 1501–2000 plants/hm2; D3: 2001–3000 plants/hm2; and D4: ≥3001 plants/hm2). The findings of this study showed that S3 demonstrated the best tree growth, with considerably higher DBH and V than S1 and S2. In addition, as the number of trees grew, the average diameter at breast height (DBH), height (H), and volume (V) all decreased greatly. Poor site (S1) suppressed the canopy, decreasing crown width (CW), crown length (CL), crown ratio (CR), crown surface area (CCSA), and crown volume (CCV), while increasing crown efficiency (CEFF). This same trend was seen in D4, where CR, CCSA, and CCV were all much smaller than the other densities, but CEFF was the highest. Subjective and objective indicators were less responsive to changes in crown growth than crown composite indicators like CCSA, CCV, CEFF, and CR. Site condition and density had a major impact on biomass accumulation, with S1 and D4 having a much lower biomass than S2, S3, D1, D2, and D3. More biomass was allocated to the stem in S3 and D1, and more biomass was allocated to branches and leaves in S2, S3, D1, D2, and D3, resulting in a nearly isotropic growth of branches and leaves. The effect of crown indicators on the biomass of each organ varied according to site condition and density. In varied site conditions, crown and DBH ratio (RCD) contributed the most to stem biomass, whereas CL contributed the most to branch and root biomass. CL had the largest effect on biomass accumulation at various densities. This study demonstrates how site condition and density affect tree and crown development and biomass accumulation, providing theoretical guidance for plantation management under climate change.

Abstract Selections on emergence time might be conflicting, suggesting the existence of the optimal emergence time for plants. However, we know little about this and how morphological plasticity contributes to the strategies of plants in response to emergence timing. To better understand this issue from a dynamic perspective, we conducted a field experiment by subjecting plants of Abutilon theophrasti to four emergence treatments (ET1 ~ ET4) and measuring a number of mass and morphological traits on them at different growth stages (I ~ IV). On day 50, 70, and/or final harvest, among all ET treatments, plants germinated in late spring (ET2) performed the best in total mass, spring germinants (ET1) and ET2 performed better in stem allocation, stem, and root diameters than later germinants (ET3 and ET4); summer germinants (ET3) had the highest reproductive mass and allocation, while late‐summer germinants (ET4) had the greatest leaf mass allocation, with greater or canalized leaf number, and root length traits than others. Plants that emerged in late spring can maximize their growth potential, while those with either advanced or delayed emergence are still capable of adaptation via allocation and morphological plasticity. Early germinants (ET1 and ET2) preferred stem growth to leaf and reproductive growth, due to sufficient time for reproduction in the growth season. With limited time for growth, plants that emerged late may prefer to quicken leaf growth (indicated by increased leaf mass allocation and leaf number) at the cost of stem or root growth for the complete life cycle, reflecting both positive and negative effects of delayed emergence.

Seed regeneration is a critical stage in the life histories of plants, affecting species' abilities to maintain local populations, evolve, and disperse to new sites. In this study, we test for local adaptations to drought in germination and seedling growth of two alpine forbs with contrasting habitat preferences: the alpine generalist Veronica alpina and the snowbed specialist Sibbaldia procumbens. We sampled seeds of each species from four populations spanning a precipitation gradient from 1200 to 3400 mm/year in western Norway. In a growth chamber experiment, we germinated seeds from each population at 10 different water potentials under controlled light and temperature conditions. Drought led to lower germination percentage in both species, and additionally, slower germination, and more investment in roots for V. alpina. These responses varied along the precipitation gradient. Seeds from the driest populations had higher germination percentage, shorter time to germination, and higher investments in the roots under drought conditions than the seeds from the wettest populations – suggesting local adaption to drought. The snowbed specialist, S. procumbens, had lower germination percentages under drought, but otherwise did not respond to drought in ways that indicate physiological or morphological adaptions to drought. S. procumbens germination also did not vary systematically with precipitation of the source site, but heavier‐seeded populations germinated to higher rates and tolerated drought better. Our study is the first to test drought effects on seed regeneration in alpine plants populations from high‐precipitation regions. We found evidence that germination and seedling traits may show adaptation to drought even in populations from wet habitats. Our results also indicate that alpine generalists might be more adapted to drought and show more local adaptations in drought responses than snowbed specialists. [ABSTRACT FROM AUTHOR]

In the natural environment, plants grow and interact with both conspecific and heterospecific neighbours under different environmental conditions. In this study, we tested whether Chenopodium quinoa Willd genotypes differ in growth performance when grown with kin and non-kin under nutrient limitation in pot partitioning treatments. Biomass accumulation, allocation, organ efficiency, and specific leaf area were measured at the end of the experiment. Response variables were differentially impacted by kinship, fertility, and barrier. Total dry mass, shoot dry mass, and root and stem allocation were greater for plants grown with kin in connected pots than with non-kin in connected pots across the nutrient treatments. Kin connected and disconnected plants had a greater specific root length, specific stem length, and average leaf mass than non-kin connected and disconnected plants. Non-kin connected and disconnected plants had greater LAR and SLA than kin connected and disconnected plants under low- and high-nutrient treatments. Plants always grew better in the presence of their kin than non-kin. These results conclude that quinoa plant production benefits from planting closely related individuals under both high- and low-nutrient conditions. [ABSTRACT FROM AUTHOR]

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Under drought stress, plants can change their morphology, physiological characteristics, and carbon allocation to maintain survival and growth. Non-structural carbohydrates (NSC) are major substrates for plant metabolism and play an important role in seedling survival and growth under drought conditions. Mongolian oak (Quercus mongolica Fisch. ex Ledeb.), a constructive species distributed in northeast China, has a high drought tolerance. However, studies on seedling growth and the NSC dynamics of Mongolian oak under different drought intensities and durations are limited. To investigate this, our study measured photosynthetic characteristics, growth, biomass, and NSC concentrations for Mongolian oak seedlings on the 0, 15th, 30th, 45th, and 60th day of the experiment under three soil moisture conditions [75% ± 5% (CK), 50% ± 5% (W1), and 23% ± 5% (W2) of soil moisture field capacity (FC)]. Results showed that the growth and biomass gradually decreased as the soil moisture decreased, but the root: shoot ratio and root biomass allocation ratio gradually increased. In the W1 treatment (moderate drought), NSC content in the stems and taproots was 7.42% and 16.39% higher than those in CK at 60 days. However, in W2 treatment (severe drought), NSC content in the stems and taproots was significantly higher than those in CK during the whole period (p < 0.05), and they were 14.14% and 26.69% higher than those in CK at 60 days. We found that, under drought stress, Mongolian oak seedlings had lower growth but higher allocation to root biomass and higher NSC content in stems and roots. Furthermore, the root system became a vital carbon sink under drought stress and was beneficial for seedling survival. [ABSTRACT FROM AUTHOR]

The arid and semiarid grassland ecosystems are characterized by limited water resources and are generally vulnerable to climate change. Understanding how plants in arid and semiarid ecosystems respond to global climatic variation is crucial for ecological restoration under a changing climate. Although the effects of climate on aboveground biomass (AGB) and belowground biomass (BGB) have been widely explored, how AGB and BGB respond to climatic variation is seldom disentangled. There is still a need to understand how plant communities respond to global climate change. In this study, we conducted a transect survey across grasslands in Inner Mongolia to capture changes in AGB and BGB in plant communities. Then, we used structural equation modelling (SEM) to explore the relationship between environmental factors and the root:shoot ratio to understand how plant communities respond to ecological drought under global climate change. Our results showed that low precipitation use efficiency (LPUE) results in a high root:shoot (HRS) ratio, and BGB was more sensitive to environmental changes. By contrast, high precipitation use efficiency (HPUE) led to a low root:shoot (LRS) ratio, and environmental factors had a greater impact on AGB. For the LPUE pattern, soil water content (SWC), pH, and soil total nitrogen (STN) mainly affected the HRS ratio. Soil water content and STN influenced the HRS ratio through a positive effect on BGB. For the HPUE pattern, SWC, STN, and plant abundance (PA) predominantly regulate the LRS ratio, while biodiversity (plant abundance) affects the LRS ratio by positively affecting AGB. Our results highlight the differential impact of precipitation use efficiency on aboveground and belowground biomass allocation. This is important for monitoring the impact of drought events on plant biomass, improving productivity assessment models in arid and semi‐arid regions, and assessing local carbon storage accurately. [ABSTRACT FROM AUTHOR]

Reforestation is one of our most promising natural climate solutions, and one that addresses the looming biodiversity crisis. Tree planting can catalyse forest community reassembly in degraded landscapes where natural regeneration is slow, however, tree survival rates vary remarkably across projects. Building a trait-based framework for tree survival could streamline species selection in a way that generalizes across ecosystems, thereby increasing the effectiveness of the global restoration movement. We investigated how traits mediated seedling survival in a tropical dry forest restoration, and how traits were coordinated across plant structures. We examined growth and survival of 14 species for 2 years and measured six below-ground and 22 above-ground traits. Species-level survival ranged widely from 7.8% to 90.1%, and a model including growth rate, below-ground traits and their interaction explained more than 73% of this variation. A strong interaction between below-ground traits and growth rate indicated that selecting species with fast growth rates can promote establishment, but this effect was most apparent for species that invest in thick fine roots and deep root structures. Overall, results emphasize the prominent role of below-ground traits in determining early restoration outcomes, and highlight little above- and below-ground trait coordination, providing a path forward for tropical dry forest restoration efforts. [ABSTRACT FROM AUTHOR]

Interaction of global change drivers affects forest resilience. Land‐use changes (land abandonment) and climate change (a higher frequency and intensity of droughts) are interacting in the Mediterranean Region. Components of resilience in secondary stem growth have been widely studied but, despite the importance of root systems in forest functionality and resilience, non‐previous studies have assessed them in coarse roots.In this study, we use Juniperus thurifera tree‐ring chronologies in coarse roots and stems to assess biomass allometry and tree resilience to drought events comparing two stages of a forest expansion gradient (mature forests and transition zone) in Alto Tajo Natural Park. We extracted cores of stems and coarse roots in 48 trees distributed in different developmental stages and calculated cross‐sectional area increments, root‐stem allometric relationship and resilience components for both organs in each individual for two drought events (2005 and 2012).Stem and root growth as well as its allometric exponent were higher in the transition zone than in mature forests. Both organs exhibited a trade‐off between resistance and recovery in mature forests but maintenance of higher values in the transition zone. Resilience did not show differences between organs being higher in the transition zone than in mature forests. However, relative resilience in roots in the transition zone was higher than in mature forests, without differences in stems between stages. Finally, the 2012 drought event showed a higher impact on the components of resilience than the 2005 drought event.Synthesis. This study extends the knowledge of root response to drought events and highlights the potential of land‐use legacies to reduce the negative impact of climate change by promoting increased root recovery after drought events in trees established in past agricultural lands. [ABSTRACT FROM AUTHOR]

Continuous light (CL) is available throughout the polar day for plants in the Arctic during the growing season, whereas provenances of the same species experience a very different environment with non-CL (NCL) just a few latitudes to the south. Both provenances need to acclimate to climate warming, yet we lack comprehensive understanding of how their growth, photosynthesis and leaf traits differ. Further, the provenances presumably have morphological and physiological adaptations to their native environments and therefore differ in response to photoperiod. We tested the height growth, leaf longevity, biomass accumulation, biomass allocation and rates of gas exchange of northern (67°N) and southern (61°N) Finnish silver birch (Betula pendula Roth) origins in CL- and NCL-treatments in a 4-month chamber experiment. Irrespective of photoperiod, 67°N had higher area-based photosynthetic rate (A net), stomatal conductance (g s) and relative height growth rate (RGR), but lower stomatal density and fewer branches and leaves than 61°N. Photoperiod affected height growth cessation, biomass and photosynthetic traits, whereas leaf longevity and many leaf functional traits remained unchanged. In CL, both provenances had lower g s, higher RGR, increased shoot:root ratio and increased sink sizes (more branching, more leaves, increased total plant dry weight) compared with NCL. In NCL, 67°N ceased height growth earlier than in CL, which altered biomass accumulation and distribution patterns. Northern conditions impose challenges for plant growth and physiology. Whether a provenance inhabits and is adapted to an area with or without CL can also affect its response to the changing climate. Northern birches may have adapted to CL and the short growing season with a 'polar day syndrome' of traits, including relatively high gas exchange rates with low leaf biomass and growth traits that are mainly limited by the environment and the earlier growth cessation (to avoid frost damage). [ABSTRACT FROM AUTHOR]

Aim: While drought and shade are critical factors that determine seedling survival and growth, whether the responses of woody seedlings to drought are facilitated, aggravated or unaffected by shade remains uncertain. Location: Global. Time period: 1993 to 2021. Major taxa studied: Woody plants. Methods: We compiled 58 studies (including 75 woody species from 33 families) in which water and light availability were simultaneously manipulated, and conducted a meta‐analysis on the acclimation and adaptive responses of biomass production and allocation and leaf traits to drought and/or shade. Results: Shade alleviated the adverse impact of drought on photosynthesis (A) by decreasing stomatal limitation and photoinhibition, and increasing leaf relative water content, and thus facilitated biomass production, but shade aggravated the effect of drought on osmotic adjustment as evidenced by the lack of responses of osmotic potential at the full turgor and modulus elasticity at the maximum turgor to drought under shade. The effects of drought and shade on biomass allocation and specific leaf area were orthogonal. Biomass responses to drought and its interaction with shade were least responsive for drought‐tolerators, but the individual and interactive effects of shade and drought on most traits showed little dependence on shade tolerance. Drought–shade interaction increased root biomass and root mass fraction more for deciduous angiosperms than for evergreen angiosperms. Main conclusions Both shade and drought had negative impacts on biomass production and photosynthesis, but their interaction had positive effects that were less significant for drought‐tolerators and evergreen angiosperms. In contrast to shade, drought increased biomass allocation to roots, but shade and drought had orthogonal effects on biomass allocation and leaf morphology. These acclimation and adaptive responses of woody seedlings to drought and shade individually and interactively have important implications for predicting woody plant growth and distribution under global climate changes. [ABSTRACT FROM AUTHOR]

The biodiversity of aboveground plants and belowground microbes is key for plant communities resisting exotic plant invasion. Whether the soil legacy effects after the invasion are related to the diversity of the invaded community is less studied. Soils from invaded communities were collected and potted to investigate the effects of the invasive community’s legacy on the biomass allocation of plants that later grew in these soils. The plots where native plants were present had relatively high nutrient levels (except for available nitrogen) compared to the monodominance communities invaded by Chromolaena odorata. This also indirectly suggests that the severe invasion of C. odorata depleted the nutrients in the soil to a greater extent. When soils were from communities with only C. odorata or one native plant, their biotic legacies showed a significantly positive effect on biomass accumulation of subsequent invasive plants, but this positive effect became negative when more than two native plants were present in the invaded community. This result indicated that the effect of biological resistance increases with the number increase of native species in the invaded communities. The soil legacy effect of the invaded communities on subsequent plants depended on the diversity of native plants. This study can provide insights into the mechanisms of soil biological resistance to exotic plant invasion and provide a theoretical basis for the removal of soil legacy effects after the exotic plant invasion. [ABSTRACT FROM AUTHOR]

【Objective】The purpose of this study was to reveal the effects of flat stubble in different seasons on biomass allocation and allometric growth of Pinus yunnanensis Franch. 【Method】The biomass accumulation and biomass allocation patterns of P. yunnanensis in spring, summer and autumn were studied by digging method and weighing method, and the allometric growth relationships between organs and total biomass, organs and organs biomass were analyzed by allometric growth analysis method. 【Result】Except lateral roots, the biomass accumulation of other components in spring was significantly higher than that in summer and autumn; In spring and autumn, the biomass distribution of needles and stems was significantly greater than that of other components, while in summer, the biomass distribution of stems was significantly greater than that of other components; In spring and summer, the biomass distribution of lateral roots was significantly lower than that of other components, while in autumn, the sprouting was significantly lower than that of other components. The trade-off law of underground and aboveground biomass was as follows: the underground and aboveground biomass grew at the same speed in spring and summer, and tend to grow above the ground in autumn. In different seasons of flat stubble, the growth rate of needles in seedling components maintained the maximum, followed by lateral roots; However, there were significant differences in the growth rate between taproot and stem, taproot and needle, sprout and needle, sprout and taproot component biomass, indicating that the allometric growth relationship was significantly affected by the flat stubble season. The effects of flat stubble on the growth rate of seedling components in different seasons were discrepant, the highest growth rate was needle leaf, followed by lateral root; From the growth rate between sprouts and biomass of each component, the growth rate of sprouts with flat stubble was the fastest in autumn, the second in spring and the slowest in summer. 【Conclusion】The flat stubble season changed the biomass accumulation and biomass distribution mode of P. yunnanensis. The flat stubble season had different effects on the allometric growth of each component, but the needle and lateral roots in the seedling component always maintained a large growth rate, which was not affected by the flat stubble season. Considering comprehensively that P. yunnanensis seedlings with flat stubble should be stubble in spring or autumn, the biomass of flat stubble initiation zone in spring was large, and the growth rate of flat stubble initiation zone in autumn was fast. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Northwest A & F University - Natural Science Edition is the property of Editorial Department of Journal of Northwest A&F University (Natural Science Edition) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Chapingo Serie Ciencias Forestales is the property of Universidad Autonoma Chapingo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background and Aims Our understanding of plant responses to biotic and abiotic drivers is largely based on above-ground plant traits, with little focus on below-ground traits despite their key role in water and nutrient uptake. Here, we aimed to understand the extent to which above- and below-ground traits are co-ordinated, and how these traits respond to soil moisture gradients and plant intraspecific competition. Methods We chose seedlings of five tropical tree species and grew them in a greenhouse for 16 weeks under a soil moisture gradient [low (drought), medium and high (well-watered) moisture levels] with and without intraspecific competition. At harvest, we measured nine above- and five below-ground traits of all seedlings based on standard protocols. Key Results In response to the soil moisture gradient, above-ground traits are found to be consistent with the leaf economics spectrum, whereas below-ground traits are inconsistent with the root economics spectrum. We found high specific leaf area and total leaf area in well-watered conditions, while high leaf dry matter content, leaf thickness and stem dry matter content were observed in drought conditions. However, below-ground traits showed contrasting patterns, with high specific root length but low root branching index in the low water treatment. The correlations between above- and below-ground traits across the soil moisture gradient were variable, i.e. specific leaf area was positively correlated with specific root length, while it was negatively correlated with root average diameter across moisture levels. However, leaf dry matter content was unexpectedly positively correlated with both specific root length and root branching index. Intraspecific competition has influenced both above- and below-ground traits, but interacted with soil moisture to affect only below-ground traits. Consistent with functional equilibrium theory, more biomass was allocated to roots under drought conditions, and to leaves under sufficient soil moisture conditions. Conclusions Our results indicate that the response of below-ground traits to plant intraspecific competition and soil moisture conditions may not be inferred using above-ground traits, suggesting that multiple resource use axes are needed to understand plant ecological strategies. Lack of consistent leaf–root trait correlations across the soil moisture gradient highlight the multidimensionality of plant trait relationships which needs more exploration. [ABSTRACT FROM AUTHOR]

When it comes to root and mycorrhizal associations that define resource acquisition strategy, there is a need to identify the leading dimension across root physiology, morphology, architecture and whole plant biomass allocation to better predict the plant's responses to multiple environmental constraints. Here, we developed a new framework for understanding the variation in roots and symbiotic fungi by quantifying multiple-scale characteristics, ranging from anatomy to the whole plant. We chose the rubber (Hevea brasiliensis) grown at three elevations to test our framework and to identify the key dimensions for resource acquisition. Results showed that the quantities of absorptive roots and root system architecture, rather than single root traits, played the leading role in belowground resource acquisition. As the elevation increased from the low to high elevation, root length growth, productivity and root mass fraction (RMF) increased by 2.9-, 2.3- and 13.8-fold, respectively. The contribution of RMF to the changes in total root length was 3.6-fold that of specific root length (SRL). Root architecture exhibited higher plasticity than anatomy and morphology. Further, mycorrhizal colonization was highly sensitive to rising elevations with a non-monotonic pattern. By contrast, both leaf biomass and specific leaf area (traits) co-varied with increasing elevation. In summary, rubber trees changed root system architecture by allocating more biomass and lowering the reliance on mycorrhizal fungi rather than improving single root efficiency in adapting to high elevation. Our framework is instructive for traits-based ecology; accurate assessments of forest carbon cycling in response to resource gradient should account for the leading dimension of root system architecture. [ABSTRACT FROM AUTHOR]

Water regime plays a determinant role in plant community development and patterns of plant zonation in wetlands. The waters located in the middle reach of the Yangtze River (China) have experienced a large decrease in wetland area from human activities for a long time, especially after the hydrological drought events in recent years. This outdoor study was conducted to clarify the morphological responses and reproductive strategy of Vallisneria spinulosa to water depth gradients (0.6 m, 1.0 m, 1.5 m) and to drawdown (down to 0.3 m). In static water, water depth of 1.0 m was the best condition for V. spinulosa to grow, manifested as high biomass of vegetative parts, tubers and sexual structures. However, V. spinulosa growing in water depth of 1.5 m was able to adapt to the decline in water depth in autumn, expressed as increased ramet number, stolon weight and belowground biomass. The low water depth of 0.6 m produced small plants with slight vegetative biomass and drawdown produced more tuber biomass. The drawdown caused a decline in vegetative ratio of V. spinulosa. Moreover, it caused an increase in clonal ratio at water levels of 1.5 m and 0.6 m, and a decline in sexual ratio at water levels of 1.5 m and 1.0 m. The results show that under the condition of relatively large fluctuations in water level, V. spinulosa will reduce the allocation of sexual biomass and increase the allocation of clonal biomass in order to cope with environmental changes so that it can proliferate better. Thus, water level changes have a great influence on the growth and reproduction of V. spinulosa. [ABSTRACT FROM AUTHOR]

Investigating the response of alien invasive plants to water level gradient in wetlands is important for developing strategies to prevent invasions by alien plants in these ecosystems. Controlled experiments were conducted to investigate the response of root morphology in the alien invasive plant Amaranthus retroflexus to water level gradient. The plants were planted in three water levels from low to high that resulted in drought, wet and flooded conditions. The results showed that biomass and allocation of A. retroflexus under flooded conditions were significantly lower than the other two treatments (p <.05). Root morphological parameters (root mean diameter, root length, root surface area and root volume) were maximum under wet condition, followed by dry and flooded conditions, and the differences were significant among the treatments (p <.05). Special root length and special root surface area were also significantly greater under wet condition than under dry condition (p <.05). The results indicate that water level gradient in wetlands affects root biomass and morphology of A. retroflexus, which has the highest growth potential under wet condition. The roots of the plant also exhibited plasticity to water level gradient. Therefore, maintaining a high water level in wetlands could restrict the growth of A. retroflexus and prevent its successful invasion. Moreover, a high water level is beneficial to the growth of wetland plants and further decreases the invasibility of wetland ecosystems. [ABSTRACT FROM AUTHOR]

Aboveground litter production is an important biogeochemical pathway in forests whereby carbon and nutrients enter soil detrital pools. However, patterns and controls of aboveground litter production are often based on an understanding of how autumnal, foliar inputs are related to aboveground tree production. Here we use three separate data sources of aboveground litter production in temperate forests to ask how aboveground woody productivity affects foliar litter production in light of other factors, such as the climate sensitivity of litter production and the seasonality of not only foliar but also fine woody debris and reproductive litter inputs. We find that foliar litter production increases with aboveground woody production, and this relationship is modified both by plant functional group and climate. Basal area also provides a crucial control on litter production. Conifer forests produce approximately half as much foliar litter as broadleaf deciduous forests. Litter production is sensitive to both among-site and among-year variation in climate, such that more litter is produced in warmer, wetter locations and years. On average 72% of aboveground litter is foliar material, with the remaining split about evenly between fine woody debris and reproductive material, and although about 88% of broadleaf litter falls during autumn, only about 61% of needles, 37% of fine woody debris and 43% of reproductive material falls during the same period. Together these results illustrate key differences in the controls of litter production in coniferous and deciduous forests, and highlight the importance of often overlooked litter fluxes, including non-autumn and non-foliar litterfall. [ABSTRACT FROM AUTHOR]

Heavy metal accumulation in soils has been one of the environmental and ecological issues, as it caused life and biodiversity problems. However, many invasive plants can survive in heavy metal polluted areas, but little is known about the invasiveness while under different densities either with native species or themselves. In this study, a greenhouse experiment was performed to examine how cadmium contamination with different concentrations (0, 100, and 200 mg/kg) may influence the interspecific competition between invasive plant Alternanthera philoxeroides and the landscape grass T. regens, as well as the intraspecific competition of A. philoxeroides with different densities. The results showed that stronger interspecific competition would alleviate cadmium damage to both A. philoxeroides and T. regens, but the two species adopted different allocation strategies. A. philoxeroides allocated more biomass to belowground and less to aboveground, while T. regens showed exactly the opposite allocation strategy. There was a significant density effect of intraspecific competition on A. philoxeroides. That is to say, with the increase of A. philoxeroides density, the cadmium stress on the growth of A. philoxeroides decreased. Our findings provide a theoretical basis and technical support for the effective control of A. philoxeroides invasion, as well as the restoration and reconstruction of green vegetation. [ABSTRACT FROM AUTHOR]

Root growth patterns respond to small-scale resource heterogeneity and the presence of roots of neighboring plants, but how a plant integrates its responses to these cues is not well understood. In the presence of neighbors, plants may shift allocation to roots as a consequence of plant size and root:shoot allometry, as a response to resource depletion by neighbors, or through a direct response to neighbor presence. The same response pathways also have the potential to alter proliferation in resource-rich patches in soil.Four species of grassland plants were grown in the greenhouse as single plants, monocultures, and mixtures. Root length allocation as a function of shoot mass was examined for background soil and fertilized patches. Plants grown with same-species neighbors followed the same allometric trajectory as single plants for root length in background soil, so any change in root allocation was due only to reduced plant size. Root proliferation in patches declined with neighbors, consistent with a response to resource depletion. Mixtures overproduced roots in both background soil and in patches, relative to plants of the same size in monocultures.

• Grassland biomass allocation is sensitive to natural conditions and grazing practices. • Differences in grassland biomass allocation existed among continents. • Grazing practice affected aboveground part and the ratio of it to below-ground part. • Climate has a stronger role in regulating grassland biomass allocation than altitude. • Warming may exert a more detrimental effect on grazed grasslands than non-grazed ones. Biomass allocation in grasslands is key to understanding plant response to environmental changes and grazing management. Yet, global studies on how this split between above-ground and below-ground biomass varies across continents and grazing practices are notably scarce. We employ a comprehensive field-oriented grassland database to examine differences in total net primary productivity (TNPP), above-ground net primary productivity (ANPP), below-ground net primary productivity (BNPP), and the BNPP to ANPP ratio across continents and between grazed and non-grazed grasslands. Oceania showed the greatest ANPP (916 g·m−2·a−1), while Asia had the lowest (192 g·m−2·a−1). BNPP values were similar among Oceania, Africa, and Asia (∼600 g·m−2·a−1), significantly exceeding those in Europe (289 g·m−2·a−1) and North America (408 g·m−2·a−1). South America, Africa, and Oceania had the highest TNPP (around 1418 g·m−2·a−1 to 1466 g·m−2·a−1), while Europe had the lowest TNPP (344 g·m−2·a−1). The BNPP to ANPP ratio was highest in South America (4.17) and Asia (3.46). Global differences in TNPP and BNPP between grazed and non-grazed grasslands were minimal, but ANPP (169 g·m−2·a−1 and 198 g·m−2·a−1, respectively) and the BNPP to ANPP ratio (4.87 and 2.40, respectively) differed significantly. Across continents and grazing practices, climate had a greater role in regulating grassland biomass allocation than altitude, and warming may have a more detrimental impact on grazed grasslands than non-grazed grasslands. Distinct biomass allocation trends under various continental and grazing conditions exert effects on the economic and ecological functions of grasslands. Our study underscores the need for balanced grassland utilization strategies at a global scale. This involves optimizing grazing in high ANPP grasslands and protecting those with significant BNPP, thereby contributing to a sustainable and ecologically sound use of grasslands in the future. [ABSTRACT FROM AUTHOR]

Increasing concentration of ground level O 3 and its negative impacts on agricultural output is well documented, however, the response of leguminous crop plants is still sparsely cited. Given their nutritional richness, legume seeds are widely esteemed as a crucial dietary staple worldwide, prized for their abundance of oil, protein, dietary fiber, and low-fat characteristics. Termed as the "poor man's meat" due to their high-quality protein, they hold immense economic value. Acknowledging the significance of legumes, a field experiment was conducted to understand the physiological and antioxidant responses, stomatal characteristics, and yield response in three cultivars of Pisum sativum L. (K Agaiti, K Uday and K Damini), exposed to elevated ozone (O 3). In the present study, Pisum sativum cultivars were subjected to ambient (control) and elevated (+15 ppb) concentrations of O 3 , using separate sets of OTCs. Elevated O 3 stimulated the activity of the enzymes of Halliwell Asada pathway, which were responsible for the differential response of the three experimental cultivars. While K Agaiti and K Uday focused on upregulating their antioxidant defense, K Damini followed the strategy of biomass allocation. Test weight showed that K Damini was most efficient in succoring the yield losses under elevated O 3. Under elevated O 3 , test weight reduced by 8.91%, 7.52%, and 5.1%, respectively, in K Agaiti, followed by K Uday and K Damini, rendering K Agaiti most sensitive to O 3 stress. The present study not only helps us to elucidate the O 3 sensitivity of the selected experimental cultivars, it also helps us in screening O 3 tolerant cultivars for future agricultural practices. [Display omitted] • The manuscript defines the O 3 sensitivity of the selected pea cultivars. • O 3 flux encompasses the differential mechanistic responses among the selected pea cultivars. • Yield response of the different pea cultivars is not correlated with their respective O 3 flux. [ABSTRACT FROM AUTHOR]

The allocation of plant biomass above and below ground reflects their strategic resource utilization, crucial for understanding terrestrial carbon flux dynamics. In our comprehensive study, we analyzed biomass distribution patterns in 580 broadleaved and 345 coniferous forests across China from 2005 to 2020, aiming to discern spatial patterns and key drivers of belowground biomass proportion (BGBP) in these ecosystems. Our research revealed a consistent trend: BGBP decreases from northwest to southeast in both forest types. Importantly, coniferous forests exhibited significantly higher BGBP compared to broadleaved forests (p < 0.001). While precipitation and soil nutrients primarily influenced biomass allocation in broadleaved forests, temperature and soil composition played a pivotal role in coniferous forests. Surprisingly, leaf traits had a negligible impact on BGBP (p > 0.05). Climatic factors, such as temperature and rainfall, influenced biomass partitioning in both strata by altering soil nutrients, particularly soil pH. These findings provide valuable insights into understanding carbon sequestration dynamics in forest ecosystems and improving predictions of the future trajectory of this critical carbon cycle component.

Abstract Seed regeneration is a critical stage in the life histories of plants, affecting species' abilities to maintain local populations, evolve, and disperse to new sites. In this study, we test for local adaptations to drought in germination and seedling growth of two alpine forbs with contrasting habitat preferences: the alpine generalist Veronica alpina and the snowbed specialist Sibbaldia procumbens. We sampled seeds of each species from four populations spanning a precipitation gradient from 1200 to 3400 mm/year in western Norway. In a growth chamber experiment, we germinated seeds from each population at 10 different water potentials under controlled light and temperature conditions. Drought led to lower germination percentage in both species, and additionally, slower germination, and more investment in roots for V. alpina. These responses varied along the precipitation gradient. Seeds from the driest populations had higher germination percentage, shorter time to germination, and higher investments in the roots under drought conditions than the seeds from the wettest populations – suggesting local adaption to drought. The snowbed specialist, S. procumbens, had lower germination percentages under drought, but otherwise did not respond to drought in ways that indicate physiological or morphological adaptions to drought. S. procumbens germination also did not vary systematically with precipitation of the source site, but heavier‐seeded populations germinated to higher rates and tolerated drought better. Our study is the first to test drought effects on seed regeneration in alpine plants populations from high‐precipitation regions. We found evidence that germination and seedling traits may show adaptation to drought even in populations from wet habitats. Our results also indicate that alpine generalists might be more adapted to drought and show more local adaptations in drought responses than snowbed specialists.

IntroductionThe biomass and nutrient allocation strategies in plants are fundamental for predicting carbon storage and mineral and nutrient cycles in terrestrial ecosystems. However, our knowledge regarding the effects of multiple environmental factors on biomass and nutrient allocation remains limited.MethodsHere we manipulated soil composition (three levels), arbuscular mycorrhizal fungi inoculation (AMF, five levels), and root-knot nematode inoculation (RKN, two levels) using random block design to reveal the effects of these factors on biomass and nutrient allocation strategies of cherry tomato.Results and DiscussionOur results showed that biomass and nutrient allocation were affected by soil composition, AMF and RKN individually or interactively. The biomass and nutrient allocation in cherry tomato shows different adaptation strategies responded to the joint action of three factors. The reduction of soil nutrients increased belowground biomass allocation, and aboveground nitrogen and phosphorus concentration. AMF colonization increased aboveground biomass allocation and reproductive investment and promoted aboveground nitrogen and phosphorus inputs. Cherry tomato can mitigate the stress of RKN infection by investing more biomass and nutrients into belowground organs. Our study showed that plants can adjust their survival strategies by changing biomass and nutrient allocation to adapt to variation in soil abiotic and biotic factors. These findings contribute to our understanding of the adaptive processes of plant biomass and nutrient allocation strategies under multiple environmental factors.

Biomass allocation strategies among geophytes and non-geophytes generally determine the ecological adaptation and impacts of herbaceous plants. Although geophytes and non-geophytes are key components of the biodiversity of subtropical forest ecosystems, strategies for biomass allocation of both remain unknown. In this study, 695 individual herbaceous plants were collected from low, middle, and high altitude regions in Qianjiangyuan National Park. We analyzed the biomass and allometric trajectories of the leaves, stems, roots, and underground storage organs of whole herbs, geophytes, and non-geophytes. The results showed that: (1) The overall allometric trajectory of understory herbs changed with increase in altitude. Allocation was reduced to stems and leaves and increased to roots. (2) In geophytes, the allocation was reduced to leaves and stems and increased to underground storage organs and roots, which follows the optimal partitioning theory. In the biomass trade-off of the aboveground parts, the stem is preferred. (3) However, the allometric trajectories of non-geophytes are less susceptible to changes in the altitude, and the biomass allocation strategy depends only on plant size which follows allometric partitioning theory. In the biomass trade-off of the aboveground parts, the leaves are preferred. Totally, geophytes and non-geophytes adopted different biomass allocation strategies as adaptations to altitudinal changes in the environment. The plant functional type is the major determinant of biomass allocation in herb species. This study has implications for the management practices of herbaceous plants and predicting changes in understory vegetation.

Tropical forests continue to suffer from various kinds of disturbances in the Anthropocene. An immediate impact of disturbances on forest ecosystems is the creation of numerous large and small canopy gaps, which dramatically affect forest structure and function. Yet, we know little about the effect of canopy gaps on forest successional trajectory. More specifically, the responses of seedlings from different successional stages to increased light intensity under large and small canopy gaps in understory remain unclear. In this study, dominant tree seedlings from early-, mid-, and late-successional stages were selected, respectively from a tropical montane forest in Hainan Island, China to study their growth rate, biomass and traits. Our results showed that the light condition under small canopy gaps (SG, 10–15% of full sunlight) and large canopy gaps (LG, 40–50% of full sunlight) induced greater increment of relative growth rates for seedlings from early- and mid-successional stages relative to that in late-successional stage. Both SG and LG also significantly increased photosynthesis rate, leaf area (LA), light saturation point (LSP), root mass ratio (RMR) and root: shoot ratio, but decreased specific leaf area (SLA) of seedlings across successional stages. Tree seedlings from the early-successional stage displayed the greatest decrease in leaf mass ratio, increase in LA, LSP, and RMR, in comparison to those from mid- and late- successional stages. Light condition and SLA were the most important factors for seedlings’ relative growth rate across successional stages. SLA connected the interaction between the light condition and successional stage on seedlings’ growth, thereby jointly explaining the 93% variation of seedlings’ growth, combining with area-based light saturated rate of CO2 assimilation. Our study highlights the distinct effect of disturbance-induced canopy gaps on seedling regeneration in the understory in tropical forest due to the variation of light intensity. We suspect that the seedlings from late-successional stage will recover relatively slow after disturbances causing canopy losses, which can have detrimental impacts on structure feature and successional trajectory in tropical forest, as well as forest-based ecosystem services.

Karst landscapes typically have extremely poor soil fertility, water retention, and water holding capacity, making these landscapes extremely unusual among terrestrial ecosystems. Owing to the complexity of karst areas on a microsite level, a variety of different microhabitats have often been created in a very small area in karst areas, and the differences have facilitated the differentiation of species within the region. This study involved an experiment on Ampelocalamus luodianensis (Poaceae), a bamboo species that specializes in karst habitats, to discover the adaptation strategies this plant uses in this area. Furthermore, a random sampling method was used to measure different variables and their correlation, such as plant biomass, soil temperature, soil mechanical composition, alkali nitrogen, Olsen-K, PZOS (meaning effective phosphorus), soil water content, pH, and organic matter. The findings showed that the distribution of biomass varied in different years in the same habitat. In particular, the ratio of above-ground biomass to below-ground biomass during a quadrennium at the earthy surface was visibly lower than in the remaining three microhabitats. Also, the highest above-ground biomass to below-ground biomass ratios of annual, triennial, and quadrennial A. luodianensis were of those plants living in stone crevices, while biennial ratios of plants in stone gullies were affected by the mechanical composition of soil and by temperature. In conclusion, plant biomass allocation in A. luodianensis was affected by a combination of environmental factors. Thus, the biomass allocation strategy of A. luodianensis was in line with the isokinetic/allometric biomass allocation theory, which was relevant to soil mechanical composition and temperature, perhaps caused by the plant itself and the special karst environment.

The recalcitrant understory fern layer is an important ecological filter for seedling regeneration, yet how the fern layer influences seedling regeneration dynamics remains unclear. Here we transplanted 576 seedlings of four dominant tree species, Castanopsis fargesii, Lithocarpus glaber, Schima superba and Hovenia acerba, to the treatments of Diplopterygium glaucum retention and removal under an evergreen broad-leaved forest in eastern China. We monitored the survival, growth and biomass data of these seedlings for 28 months, and then used generalized linear mixed models to evaluate the treatment effects on seedling survival, growth, biomass and rootshoot ratio. Our results showed that fern retention significantly inhibited the seedling establishment of all four species. During the seedling development stage, the seedling relative growth rate of L. glaber decreased under fern retention, which was not the case for the other three species. Root-shoot ratio of C. fargesii and L. glaber increased significantly under fern retention. Our findings provide new evidence of the filtering effect of a recalcitrant fern understory. Notably, we observed that the response of tree seedlings to the recalcitrant fern understory was more sensitive in the establishment stage. Finally, our work highlights that the filtering effect of the recalcitrant fern understory changes depending on the regeneration stages, and that shadetolerant species, C. fargesii and L. glaber were even more affected by fern disturbed habitats, suggesting that effective management should attempt to curb forest fern outbreaks, thus unblocking forest recruitment. [ABSTRACT FROM AUTHOR]

Anthropogenic nitrogen (N) deposition exerts profound influence on the composition and function of native ecosystems, commonly resulting in reduced plant richness and increases in nonnative plant invasion. Identifying differences in plant N responses and functional traits could help to explain the ongoing invasion and biological impoverishment of ecosystems subject to N deposition.We compared the growth, emergence phenology and functional traits of 30 native and invasive annual plant species under high and low N availability, with the goal of evaluating if invasives exhibit functionally dissimilar responses to N compared with the native species they displace.Invasives grew larger than natives, especially under increased N availability. Overall, invasives and natives did not differ in emergence phenology. However, these groups of species differed in relationships between growth and days to emergence, and N addition further strengthened these differences; invasives consistently grew larger than natives that emerged around the same time, whereas natives showed a strong negative effect of delayed emergence on plant growth.Relative N responses for measures of plant growth and allocation did not differ between native and invasive species, but invasives exhibited greater plasticity in physiological traits. This included significantly lower leaf N content, higher CN ratios and greater water‐use efficiency (WUE) in plants grown under high N. Invasives also showed functionally different patterns of growth and water use. Across species, invasives showed a positive relationship between shoot growth and WUE. Native species showed a trade‐off between root allocation and WUE, whereas invasives displayed high values for WUE even despite reduced root: shoot ratios under high N.Our results highlight the ability of invasives to rapidly accrue biomass, disproportionately benefit from early emergence and N addition and use water efficiently despite rapid growth. Natives, on the other hand, pay a higher cost for delayed emergence and may experience trade‐offs between growth and water use. The more pronounced functional differences between natives and invasives observed under high N likely play an important role in driving invasion and reduced species diversity under N enrichment. These differences could be used to inform successful management strategies for N‐impacted and water‐limited ecosystems. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Purpose: Roots are the mean absorbing organ of plants and an important part of material circulation in ecosystems. Understanding long-term root system development and its response to soil water availability can help to elucidate carbon cycling and plant resource uptake strategies in forest plantations under climate change. Methods: We created a soil water content (SWC) gradient in a poplar forest using irrigation. During the six-year rotation, we determined biomass allocation by dissecting 45 sample trees, and measured spatial–temporal distribution and morphology of fine roots through analysis of 3984 root samples. Observations occurred as stands developed through canopy closure and experienced increasing inter-tree competition. Results: Biomass allocation initially responded positively to low SWC while rooting depth was unaffected. As stands developed, biomass allocation differences gradually disappeared, and low SWC caused deeper root distribution. Morphological responses to depth emerged after the first year. In shallow soil, specific root length and fine-root diameter were lower while root tissue density was greater than those below 50 cm depth. Conclusion: Soil water availability can affect biomass allocation and determine the soil layer with high exploration intensity, but both of these effects depend on stand development. During development, horizontal root system expansion takes precedence over vertical expansion. Besides, our finding implies that functional divergence of fine roots may occur gradually with stand development, with finer diameter roots in shallow soil perhaps functioning mainly for absorbing soil resources while low-density, high-diameter roots in deep soil functioning primarily for expanding the root system and exploring for limiting soil moisture resource. [ABSTRACT FROM AUTHOR]

Spartina anglica (hereafter Spartina) is an invasive perennial marsh grass shifting hydrodynamic regime and sediment characteristics in invaded area, thereby reducing macrobenthic diversity. There have been only a few studies focusing on the patch structure of Spartina according to size and its effects on macrofauna. A field experiment was conducted to identify effects of Spartina patches where they have been introduced no later than 5 years after invasion occurred on macrofauna assemblages in Ganghwa Island, South Korea. The survey area was divided into two sections according to vegetation: (1) Suaeda japonica vegetation from 0 to 60 m away from the levee, and (2) bare mudflat from 60 to 90 m away from the levee. The patch sizes of Spartina were categorized into small (1–4 m2), medium (5–11 m2), and large (13–40 m2) in area with four replicates for each section. The biomass ratio of the belowground and aboveground in the small size patch of Spartina was significantly higher than those in the medium and large size patch of Spartina. It indicated that more resource was allocated to rhizomes in small size patch with short invasion history (1 ~ 2 years). After Spartina invaded, macrofauna richness (70%), Shannon–Wiener diversity (80%), and density (67%) were decreased. However, infaunal deposit-feeding polychaete Perinereis linea and epifaunal gastropods Batillaria cumingi and Lactiforis takii increased by Spartina. Ordination of macroinvertebrate assemblages separated the habitat with Spartina invasion from the adjacent uninvaded tidal flat and Suaeda japonica habitats. This study offers a significant insight into early invasion strategies of an aggressive plant invader, Spartina for management of coastal wetlands and its impacts on macrofaunal assemblages. [ABSTRACT FROM AUTHOR]

Copyright of Xinjiang Agricultural Sciences is the property of Xinjiang Agricultural Sciences Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The natural regeneration of seedlings is a key factor for forest succession. Nevertheless, studies explaining the mechanism of growth and biomass allocation in regenerated seedlings after disturbance are lacking. Therefore, we measured the growth, biomass accumulation, and biomass allocation in current-age seedlings of Pinus massoniana after selective logging (logging of competitive trees, LCT; logging of inferior trees, LIT; and unlogged control, CK), and established structural equation models (SEMs) among the spatial structure characteristic indexes of the stand, environmental factors, and biomass allocation in di erent organs. As compared to the CK, the mingling index (M), uniform angle index (W), opening degree (O), soil organic carbon (SOC), available nitrogen (SAN), available phosphorus (SAP), available potassium (SAK), and bulk density (SBD) significantly increased (p < 0.05), while the competition index (CI) and neighborhood comparison (U) significantly decreased after logging (p < 0.05). After the LCT, seedling branch biomass improved, with an increase in the ground-diameter, crown-root ratio, and seedling quality index. More biomass was allocated to foliage and roots by an increase in the height and height-diameter ratio under the LIT. In the CK, increasing stem biomass helped the seedlings absorb and utilize more light. The Pearson correlation coefficient showed that biomass allocation to organs was independent, and seedlings adopted the strategies of heterogeneous adaptation and growth, thereby resulting in the separation of the allocation patterns among the organs. As per the redundancy analysis (RDA), CI was the main factor in biomass allocation. Environmental factors had direct e ects on biomass allocation to organs, while the stand spatial structure characteristic indexes had indirect e ects on biomass allocation based on SEMs. In summary, the LCT had significant, albeit indirect, effects on SOC, SAN, and SBD by reducing the CI for the regeneration and growth of seedlings in the stand, which was of great significance to the sustainable development of the forest stand of P. massoniana. [ABSTRACT FROM AUTHOR]

Across tropical ecosystems, global environmental change is causing drier climatic conditions and increases in nutrient depositions. Such changes represent large uncertainties due to unknown interactions between drought and nutrient availability in controlling ecosystem net primary productivity (NPP). Using a large-scale manipulative experiment, we studied whether nutrient availability affects the responses of three component NPP fluxes (stem growth, fine roots production, and litterfall) to through-fall exclusion in 30-year-old unmanaged mixed plantations of six tree species native to the tropical dry forest of Costa Rica. We used a factorial design with four treatments: control (CN), fertilization (F), drought (D), and drought+fertilization (D+F). While we found that a 13-15% reduction in soil moisture only led to modest effects in the studied ecosystem processes, NPP increased as a function of F and D+F. At the same time, NPP increases with nutrient additions were larger in the plots without throughfall exclusion. The relative contribution of each biomass flux to NPP varied depending on the treatment, with woody biomass being more important for F and root biomass for D+F and D. Moreover, seasonal canopy cover was maintained longer in the fertilized plots. Belowground processes such as nodulation and microbial carbon use efficiency (CUE) also responded to experimental treatments, with a decrease in nodulation for F plots and an increase in CUE for F and D plots. Species functional type (i.e., N-fixation or deciduousness) and not the experimental manipulations were the main source of variation in tree relative growth rates. Our results emphasize that nutrient availability moderately constrains ecosystem processes in tropical dry forests, but this depends on water availability. [ABSTRACT FROM AUTHOR]

Different organ morphologies determine the manner in which plants acquire resources, and the proportion of biomass of each organ is a critical driving force for organs to function in the future. Regrettably, we still lack a comprehensive understanding of root traits and seedling biomass allocation. Accordingly, we investigated and collected the seedling root morphological traits and biomass allocation of 50 annual ephemeral species to clarify the adaptation to environment. The findings of this study showed that there was a significantly negative correlation between root tissue density (RTD) and root diameter (RD) (p < 0.05), which did not conform to the hypothesis of the one-dimensional root economics spectrum (RES). On this basis, we divided 50 plant species into those rooted in dense or gravelly sand (DGS) or loose sand (LS) groups according to two soil conditions to determine the differences in root strategy and plant strategy between the two groups of plants. Our study revealed that the species rooting DGS tend to adopt a high penetration root strategy. However, the species rooting LS adopt high resource acquisition efficiency. At the whole-plant level, 50 species of ephemerals were distributed along the resource acquisition and conservation axis. Species rooting DGS tend to adopt the conservation strategy of high stem biomass fraction and low resource acquisition efficiency, while species rooting LS tend to adopt the acquisition strategy of high root and leaf biomass fraction and high resource acquisition efficiency. The research results provide a theoretical basis for the restoration and protection of vegetation in desert areas. [ABSTRACT FROM AUTHOR]

Afforestation is conducive to improving ecosystem service functions and ecosystem diversity in the Mu Us Sandy Land, however, the important attribute of biomass for Mongolian pine (Pinus sylvestris var. mongolica Litv.) plantations has yet to be accurately evaluated. This study aimed to develop additive allometric biomass equations for the species and evaluate biomass partitioning patterns within tree components. A total of 131 trees were measured for stem, branch, and leaf biomass by destructively sampling and tree climbing, with the latter as a supplement. For each biomass component, we tested three equations with the diameter at breast (D) alone, height (H) as additional, and diameter in combination with height (D2H) as predictors using the weighted least squared method. Weighted nonlinear seemingly unrelated regression was adopted to fit a system of additive allometric biomass equations utilizing the selected equations. A leave-one-out cross-validation method (the jackknife procedure) was used to assess the predictive ability. The biomass partitioning pattern was evaluated by calculating the ratios. The results revealed that the diameter alone is a good predictor for branches and foliage biomass estimates, while the stem requires H included to improve estimation accuracy. Mongolian pine allocates relatively more biomass to the crown (51.4%) compared to the stem (48.6%). Branch biomass fraction increased monotonously with increasing tree size while a reverse trend was observed for foliage. In conclusion, the additive models developed in this study provide a robust biomass estimation and can be extensively used to estimate Mongolian pine forests biomass in Mu Us Sandy Land. [ABSTRACT FROM AUTHOR]