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A picture model about the biophysical difference between ephemeral plants and desert shrubs. Desert shrubs have much more developed root systems than ephemeral plants in order to adapt to drought environment, and their belowground biomass is much bigger than aboveground biomass. On the contrary, ephemeral plants have much smaller root–shoot ratio, and their belowground biomass is much smaller than aboveground biomass.
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Plant biomass allocation patterns are important to understanding and predicting ecosystem carbon cycles and other important ecological processes. Consequently, many attempts have been made to study these patterns. However, most studies focus on data from species in temperate forests to the neglect of data from desert species adapted to arid conditi...
Citations
... In essence, plants adjust their functional traits to adapt the fluctuations in soil water availability (Rodriguez-Alarcon et al., 2022). Over large parts of the earth's surface, the extent of plant performance is notably controlled by the water supply more than other factors (Kramer and Boyer, 1995;Larcher, 2003;Deng et al., 2006Deng et al., , 2008Chen et al., 2019;Hu et al., 2021;Sun et al., 2021;Cao et al., 2022;Wei et al., 2022;Xiong et al., 2022). As plants could not escape the dry environment like animals, the impact of drought on plant performance of desert plants throughout their life span is particularly severe (Mukarram et al., 2021). ...
Drought profoundly affects the morpho-physiological responses of desert plants in dryland. To scrutinize the morpho-physiological responses of nitrogen (N)-fixing legumes (Ammopiptanthus mongolicus, Caragana korshinskii), N-fixing non-legumes (Elaeagnus angustifolia, Hippophae rhamnoides), and non-N-fixing plants (Nitraria tangutorum, Haloxylon ammodendron) under varied drought stress levels (75%, 50%, 25% and 5% of soil water holding capacity), a pot experiment was conducted in greenhouse. Following prolonged water deficit, carbon (C) and N stoichiometry, metabolic rates, plant growth, and biomass distribution of unstressed and stressed plants were recorded. Intensified drought significantly reduced stem, root and whole-plant biomass, with no significant changes observed in leaf dry-fresh mass ratio, specific leaf area, intrinsic water use efficiency and root to shoot ratio. However, other traits were impacted differently, reflecting distinct adaptive strategies to drought among three plant functional types (PFTs). Patterns of trait-soil water content (SWC) relationships varied across different PFTs, with N-fixing non-legumes followed by N-fixing legumes displayed greater sensitivity to SWC variations than non-N-fixing plants. This resulted in a shift from a stronger trait-SWC relationship in N-fixing non-legumes and N-fixing legumes to a less correlated relationship in non-N-fixing plants. The diverse responses to drought among PFTs suggest a shift from N limitation to water limitation as SWC decreases.
... Vegetation biomass distribution is a vital concept in plant life history, providing the basis for our understanding of plants' responses or adaptive strategies [1,2]. Plant biomass determines the ability of an ecosystem to acquire energy, thus playing a vital role in shaping the community structure and the function of the ecosystem [3][4][5][6]. ...
The relationship between plant productivity, measured according to biomass and species richness, is a fundamental focal point in community ecology, as it provides the basis for understanding plant responses or adaptive strategies. Although studies have been conducted on plant biomass and environmental factors, research concerning mountainous grassland areas is scarce. Therefore, the aim of the present study was to examine the influence of environmental factors on aboveground plant biomass in the mountainous grassland of the Mountain Zebra National Park, South Africa. Biomass distribution was uneven within the park, owing to certain species having relatively higher biomass values. These differences may be attributed to the chemical and physical properties of the soil, including carbon and nitrogen content, soil pH, and soil texture (sand, silt, and coarse fragments). A disc pasture meter was used to collect biomass data. Multiple regression analysis revealed that most environmental factors did not significantly influence plant biomass. The only environmental factor influencing plant biomass was soil pH; the influences of other factors were not statistically significant. The results of this study elucidate the interactions of environmental factors with plant biomass. Future research could investigate how environmental factors influence plant biomass, both below and above the ground in mountainous grassland.
... Although much attention has been paid to the allocation pattern of plant leaf due to its strong relationship with plant photosynthetic rate and thus plant net primary production (Chen et al, 2021), the role of non-photosynthetic organs cannot be ignored as stem serves as a mechanical support and hydraulic pathway and root absorbs water and nutrient resources (Fujimori, 2001;Poorter et al, 2012). To predict the functional equilibrium among plant organs (Poorter and Nagel, 2000), the well-known optimal allocation theory is proposed initially at the intraspecific level and then to interspecific level, which believes that plants prefer to increase the allocation of biomass to the organ parts that suffer the most severe stress in a harsh environment (Bloom et al, 1985;Chen et al, 2021Chen et al, , 2019Jevon and Lang, 2022). For example, a relatively high proportion of photosynthetic biomass is allocated to plant above-ground parts especially plant leaves when plants cannot achieve sufficient light resources such as growing in a dark environment (Sun et al, 2021;Uman˜a et al, 2021;McCarthy and Enquist, 2007). ...
... For example, a relatively high proportion of photosynthetic biomass is allocated to plant above-ground parts especially plant leaves when plants cannot achieve sufficient light resources such as growing in a dark environment (Sun et al, 2021;Uman˜a et al, 2021;McCarthy and Enquist, 2007). On the contrary, plants prefer to accelerate the growth of below-ground parts to adapt to an environment under which plants cannot achieve enough either water or nutrient resources (Sun et al, 2021;Chen et al, 2019). Therefore, optimal allocation theory suggests strong plant plasticity of plant growth in response to various environmental factors such as precipitation, temperature, light resources (Sun et al, 2021; J o u r n a l P r e -p r o o f 2019; Poorter and Nagel, 2000). ...
A central issue in plant ecology is exploring universal rules and the mechanisms under which photosynthetic energies are allocated to different organ parts. Until recently, prevalent studies focused on testing either optimal allocation theory or allometric allocation theory in predicting plant biomass partitioning patterns. However, paying much attention to the stable state prevents the development of new biomass allocation theories in transient time scales. Here, based on theories in transients and the allometric relationships in plant traits, I develop general theoretical models to study the transient perturbations of plant biomass allocated to non-photosynthetic organ parts. With both simulation and empirical approaches, I investigate the effect of plant stem diameter at breast height (DBH) on the variation of biomass allocation patterns during plant ontogeny. Results show that increases in DBH can mitigate the magnitude of the perturbations of plant biomass and biomass fractions allocated to both plant stem and root parts. The findings are robust when either deterministic or stochastic models are conducted. Moreover, empirical analyses from a large forest database in Eurasia consistently support the predictions from the theoretical frameworks. In this paper, I draw attention to the transient allocation pattern of plant biomass for non-photosynthetic organs, and I find the significant role of DBH. This work has important implications in both theoretical breakthroughs and practical applications. It not only provides the foundation to test new biomass allocation hypotheses but also directs agricultural and forest management to achieve stabilized yields.
... Overall, while climate factors had significant effects on BGBP, the interaction between plant functional traits and BGBP was largely negligible; therefore, Hypothesis 2 is more feasible than Hypothesis 3. Different types of plants exhibit variations in their allocation of AGB and BGB. Research has consistently shown that tree and shrub species generally have higher AGB, while herbaceous plants tend to allocate more resources to BGB (Chen et al., 2019b). Additionally, vegetation density plays a significant role in shaping the AGB and BGB allocation patterns (Chen et al., 2020). ...
... Younger plants typically allocate a larger proportion of resources to BGB and have a relatively lower AGB. As plants grow and develop, the AGB gradually increases, while the increase in BGB is relatively slower (Chen et al., 2019b). This pattern is related to the utilization and distribution of resources during the growth process. ...
Biomass in forests sequesters substantial amounts of carbon; although the contribution of aboveground biomass has been extensively studied, the contribution of belowground biomass remains understudied. Investigating the forest biomass allocation is crucial for understanding the impacts of global change on carbon allocation and cycling. Moreover, the question of how climate factors affect biomass allocation in natural and planted forests remains unresolved. Here, we addressed this question by collecting data from 384 planted forests and 541 natural forests in China. We evaluated the direct and indirect effects of climate factors on the belowground biomass proportion (BGBP). The average BGBP was 31.09% in natural forests and was significantly higher (38.75%) in planted forests. Furthermore, we observed a significant decrease in BGBP with increasing temperature and precipitation. Climate factors, particularly those affecting soil factors, such as pH, strongly affected the BGBP in natural and planted forests. Based on our results, we propose that future studies should consider the effects of forest type (natural or planted) and soil factors on BGBP.
... Field investigation and plant leaf samples of thirteen (13) dominant desert plant species were collected in the growing seasons (June to September) from 2013 to 2018, using standardized protocols described by Chen et al. (2019) and Deng et al. (2006). At each sampling site, three quadrats (every 30 m × 30 m) were selected randomly, and at least five fully mature leaves of dominant plants were collected. ...
Leaf functional traits (LFTs) of desert plants are responsive, adaptable and highly plastic to their environment. However, the macroscale variation in LFTs and driving factors underlying this variation remain unclear, especially for desert plants. Here, we measured eight LFTs, including leaf carbon concentration (LCC), leaf nitrogen concentration (LNC), leaf phosphorus concentration (LPC), specific leaf area (SLA), leaf dry matter content (LDMC), leaf mass per area (LMA), leaf thickness (LTH) and leaf tissue density (LTD) across 114 sites along environmental gradient in the drylands of China and in Guazhou Common Garden and evaluated the effect of environment and phylogeny on the LFTs. We noted that for all species, the mean values of LCC, LNC, LPC, SLA, LDMC, LMA, LTH and LTD were 384.62 mg g−1, 19.91 mg g−1, 1.12 mg g−1, 79.62 cm2 g-1, 0.74 g g-1, 237.39 g m-2, 0.38 mm and 0.91 g cm-3, respectively. LFTs exhibited significant geographical variations and the LNC, LMA and LTH in the plants of Guazhou Common Garden were significantly higher than the field sites in the drylands of China. LDMC and LTD of plants in Guazhou Common Garden were, however, considerably lower than those in the drylands of China. LCC, LPC, LTH and LTD differed significantly among different plant lifeforms, while LNC, SLA, LDMC and LMA didn’t show significant variations. We found that the environmental variables explained higher spatial variations (3.6– 66.3%) in LFTs than the phylogeny (1.8–54.2%). The LCC significantly increased, while LDMC and LTD decreased with increased temperature and reduced precipitation. LPC, LDMC, LMA, and LTD significantly increased, while SLA and LTH decreased with increased aridity. However, leaf elements were not significantly correlated with soil nutrients. The mean annual precipitation was a key factor controlling variations in LFTs at the macroscale in the drylands of China. These findings will provide new insights to better understand the response of LFTs and plants adaptation along environmental gradient in drylands, and will serve as a reference for studying biogeographic patterns of leaf traits.
Keywords: Leaf functional traits (LFTs), plant functional types (PFTs), phylogenetic independent contrast (PIC), convergent and divergent adaptations, phylogenetic linear mixed model (PLMM), principal components analysis (PCA), structural equation models (SEMs)
... Field investigation and plant leaf samples of thirteen (13) dominant desert plant species were collected in the growing seasons (June to September) from 2013 to 2018, using standardized protocols described by Chen et al. (2019) and Deng et al. (2006). At each sampling site, three quadrats (every 30 m × 30 m) were selected randomly, and at least five fully mature leaves of dominant plants were collected. ...
Leaf functional traits (LFTs) of desert plants are responsive, adaptable and highly plastic to their environment. However, the macroscale variation in LFTs and driving factors underlying this variation remain unclear, especially for desert plants. Here, we measured eight LFTs, including leaf carbon concentration (LCC), leaf nitrogen concentration (LNC), leaf phosphorus concentration (LPC), specific leaf area (SLA), leaf dry matter content (LDMC), leaf mass per area (LMA), leaf thickness (LTH) and leaf tissue density (LTD) across 114 sites along environmental gradient in the drylands of China and in Guazhou Common Garden and evaluated the effect of environment and phylogeny on the LFTs. We noted that for all species, the mean values of LCC, LNC, LPC, SLA, LDMC, LMA, LTH and LTD were 384.62 mg g-1, 19.91 mg g-1, 1.12 mg g-1, 79.62 cm2 g-1, 0.74 g g-1, 237.39 g m-2, 0.38 mm and 0.91 g cm-3, respectively. LFTs exhibited significant geographical variations and the LNC, LMA and LTH in the plants of Guazhou Common Garden were significantly higher than the field sites in the drylands of China. LDMC and LTD of plants in Guazhou Common Garden were, however, considerably lower than those in the drylands of China. LCC, LPC, LTH and LTD differed significantly among different plant lifeforms, while LNC, SLA, LDMC and LMA didn't show significant variations. We found that the environmental variables explained higher spatial variations (3.6-66.3 %) in LFTs than the phylogeny (1.8-54.2 %). The LCC significantly increased, while LDMC and LTD decreased with increased temperature and reduced precipitation. LPC, LDMC, LMA, and LTD significantly increased, while SLA and LTH decreased with increased aridity. However, leaf elements were not significantly correlated with soil nutrients. The mean annual precipitation was a key factor controlling variations in LFTs at the macroscale in the drylands of China. These findings will provide new insights to better understand the response of LFTs and plants adaptation along environmental gradient in drylands, and will serve as a reference for studying biogeographic patterns of leaf traits.
... Allocation of biomass by plants to different organs and structure parts (Poorter et al. 2012, Chen et al. 2019, Robinson 2022, especially plant vegetative (leaves, stems and roots) vs. reproductive structures (flowers, fruits and seeds) is a central topic in plant life history theory. Reproduction is the currency of natural selection, but plants need to grow before they can reproduce. ...
According to the original optimal reproductive allocation theory, plants should shift from vegetative growth to reproductive allocation abruptly and completely. Some plants do this, and it is also considered a good strategy for crop plants to maximize yield, but most plants shift gradually. Modified versions of the theory predict such a gradual transition from growth to reproduction. We hypothesize that kin selection can also alter the predictions of optimal allocation theory. We investigated the theoretical implications of both positive and negative kin selection on the timing of plant reproductive development using mathematical models. Under reasonable assumptions of costs and benefits, plants under kin selection are more likely to shift from growth to reproduction in an abrupt way when the initial value of the ratio between reproductive and vegetative biomass is high. Supported by empirical observations, our theoretical predictions have important implications in linking life history and energy allocation as well as for improving yields in agriculture.
... In dryland ecosystems, plants are expected to favor conservative traits, such as slower photosynthetic rate, higher leaf mass per area (LMA) and longer lifespan [27]. To resist water and nutrient stresses in drylands, perennial plants increase root proliferation and length to enhance water uptake at the expense of reducing allotment of nutrients to the above-ground part of the plant [28][29][30][31][32]. The adaptation of plants to drought and low nutrients has led to a coordinated diversity among different organs in the utilization and acquisition of nutrients [4,33]. ...
... The adaptation strategies of plants to drought also depend on their life-forms [35]. Resource acquisition and adaptations to the environment in woody and herbaceous plants have been well studied in drylands of China [31,32]. For example, herbaceous plants, in particular annual herbs with fast growth rates and short lifespans, often require more resources and nutrients and display a lower tolerance to adverse conditions, such as aridity, soil alkalinity, and soil nutrient deficiency, than woody plants [36,37]. ...
... Recently, we reported that a similar shift in response to drought stress exists in the drylands of China at an aridity level of approximately 0.8 (1-AI, where AI is the aridity index), in plant and microbial diversity, plant and soil functional traits, and biodiversity-soil multi-functionality relationships [32,[39][40][41]. Moreover, herbaceous species are dominant in low arid regions (AI > 0.2) and woody species are dominant in high arid regions (AI < 0.2), and their adaptation strategies are distinct to drought stress [31,40,41]. Although the functional traits of plants in drylands have been widely reported [28,29,32,34,42], plant trait networks remain unclear. ...
Background:
Plants accomplish multiple functions by the interrelationships between functional traits. Clarifying the complex relationships between plant traits would enable us to better understand how plants employ different strategies to adapt to the environment. Although increasing attention is being paid to plant traits, few studies focused on the adaptation to aridity through the relationship among multiple traits. We established plant trait networks (PTNs) to explore the interdependence of sixteen plant traits across drylands.
Results:
Our results revealed significant differences in PTNs among different plant life-forms and different levels of aridity. Trait relationships for woody plants were weaker, but were more modularized than for herbs. Woody plants were more connected in economic traits, whereas herbs were more connected in structural traits to reduce damage caused by drought. Furthermore, the correlations between traits were tighter with higher edge density in semi-arid than in arid regions, suggesting that resource sharing and trait coordination are more advantageous under low drought conditions. Importantly, our results demonstrated that stem phosphorus concentration (SPC) was a hub trait correlated with other traits across drylands.
Conclusions:
The results demonstrate that plants exhibited adaptations to the arid environment by adjusting trait modules through alternative strategies. PTNs provide a new insight into understanding the adaptation strategies of plants to drought stress based on the interdependence among plant functional traits.
... Leaves and soils were sampled during the growing seasons (June to September) from 2013 to 2017, using standard protocols described by Deng et al. (2006) and Chen et al. (2019). At least three representative and relatively homogeneous vegetation quadrats, each 30 m × 30 m, were selected randomly at each site. ...
... To cope with drought, desert woody plants tend to allocate more photosynthate to roots than shoots. This results in higher root: shoot ratios and enables the plant to absorb more water and minerals (Chen et al., 2019). Moreover, desert plant species have other distinct adaptive strategies for survival (Akram et al., 2020;Yao et al., 2021a). ...
Determining response patterns of plant leaf elements to environmental variables would be beneficial in understanding plant adaptive strategies and in predicting ecosystem biogeochemistry processes. Despite the vital role of microelements in life chemistry and ecosystem functioning, little is known about how plant microelement concentrations, especially their bioconcentration factors (BCFs, the ratio of plant to soil concentration of elements), respond to large-scale environmental gradients, such as aridity, soil properties and anthropogenic activities, in drylands. The aim of the present study was to fill this important gap. We determined leaf microelement BCFs by measuring the concentrations of Mn, Fe, Ni, Cu and Zn in soils from 33 sites and leaves of 111 plants from 67 species across the drylands of China. Leaf microelement concentrations were maintained within normal ranges to satisfy the basic requirements of plants, even in nutrient-poor soil. Aridity, soil organic carbon (SOC) and electrical conductivity (EC) had positive effects, while soil pH had a negative effect on leaf microelement concentrations. Except for Fe, aridity affected leaf microelement BCFs negatively and indirectly by increasing soil pH and SOC. Anthropogenic activities and soil clay contents had relatively weak impacts on both leaf microelement concentrations and BCFs. Moreover, leaf microelement concentrations and BCFs shifted with thresholds at 0.89 for aridity and 7.9 and 8.9 for soil pH. Woody plants were positive indicator species and herbaceous plants were mainly negative indicator species of leaf microelement concentrations and BCFs for aridity and soil pH. Our results suggest that increased aridity limits the absorption of microelements by plant leaves and enhances leaf microelement concentrations. The identification of indicator species for the response of plant microelements to aridity and key soil characteristics revealed that woody species in drylands were more tolerant to environmental changes than herbaceous species.
... Second, soil microbes first utilize degradable plant-derived materials for production in an iterative cell generation, growth, and death (Liang et al., 2017). Plant diversity could also increase soil microbial diversity and/or abundance because of a larger amount of plant-derived food and expanded microbial niches (Valencia et al., 2018;Chen et al., 2019). Thus, faster microbial decomposition of plant-derived detritus in the mixed communities enhanced SMF in the topsoil. ...
... S6 and S7). Higher inputs from aboveground and root detritus as well as root exudates could provide more available substrates for soil microbes (Deng et al., 2006;Chen et al., 2019) and enhance the soil total carbon and nitrogen contents (Hooper et al., 1998;Cardinale et al., 2011), the soil available carbon and nitrogen contents (Cotrufo et al., 2013), and MBC and MBN (Maestre et al., 2015), resulting in higher C-and N-related indexes in the mixed communities ( Fig. 4a and S6). In addition, saprotrophic fungi are the primary decomposers that promote decomposition and mineralization, as well as other AGB and BGB linked to these processes (Bardgett and van der Putten, 2014;. ...
The dynamics of multiple ecosystem functions (that is, multifunctionality) are closely associated with biodiversity, often show positive relationships, but the dynamics of the biodiversity‒multifunctionality relationship along soil profiles remain unclear. Eutrophication significantly affects biodiversity and soil functions, whereas the mechanisms underlying the impact of nitrogen addition on the biodiversity‒multifunctionality relationship are poorly understood. Here, we conducted a common garden experiment manipulating plant diversity and nitrogen addition to quantify the effects of biodiversity on soil multifunctionality in the topsoil and subsoil under different nitrogen addition levels. We showed that nitrogen addition had a minor impact on soil multifunctionality but weakened the positive biodiversity‒multifunctionality relationship. We also found that the positive plant diversity effect on soil multifunctionality decreased with soil depths, resulting in a weaker biodiversity‒multifunctionality relationship in the subsoil. The weak biodiversity‒multifunctionality relationship in the subsoil was caused by weakening the relationship between aboveground biomass and soil multifunctionality; nitrogen addition weakened the biodiversity‒multifunctionality relationship through the attenuation of the association of aboveground biomass and soil microbes with multifunctionality. Our study demonstrates that nitrogen addition undermines the biodiversity‒soil multifunctionality relationship and the relationship is weakened along the soil profiles, suggesting that Earth system models must represent these heterogeneous soil dynamics to accurately predict future feedbacks to global changes.
