Biomass Distribution Research Articles

Common population characteristics of direct‐seeded hybrid indica rice for high yield

AbstractDirect seeding of rice has attracted attention because of its simplicity and rapidity compared with traditional cultivation methods. However, the geographical location of the rice region in Southwest China is complex, and the common characteristics of high yield of direct seeding hybrid indica rice and the law of nutrient absorption and accumulation are still unclear. This study results demonstrated that the mean yield of high‐yield varieties (HYV) in the two ecological points increased by 17.68%–19.98% and 17.37%–27.06%, respectively, compared with low‐yield varieties (LYV). The high tillering ability and effective tillering rate of HYV promoted a large leaf area index (LAI) and a strong photosynthetic capacity and stimulated the accumulation of aboveground biomass and nitrogen, phosphorus, and potassium nutrients in rice plants, which were finally transported and allocated to the grains to maintain high yields. Correlation analysis indicated that yield and its components were closely related to spatial population structure and nutrient accumulation and allocation. In particular, LAI at the full heading stage, net photosynthetic rate, aboveground biomass from jointing to maturity stage, and nitrogen, phosphorus, and potassium accumulation and distribution from jointing to full heading stage have the strongest correlation with yield and its components. Therefore, improving the effective tillering rate and LAI, as well as the accumulation and distribution of aboveground biomass, nitrogen, phosphorus, and potassium of rice plants from jointing to full heading stage, are the common laws for the formation of high yield of direct seeding hybrid rice in different ecological areas.

Assessing land suitability and spatial variability in lucerne yields across New Zealand

Lucerne (Medicago sativa L.) is a widely grown perennial legume worldwide which can provide high biomass and protein yields, biological N fixation, deep soil water extraction and a range of ecosystems services relevant to current and future agricultural systems. The potential to expand lucerne beyond its current cultivated areas in New Zealand, and its potential productivity across the country’s contrasting climate zones, are currently unknown. To gain such insights, we estimated land suitability and spatial distribution of lucerne above-ground biomass across New Zealand lands considering contrasting growth conditions (rain-fed or irrigated for different soils types) and two simulation methods of different complexity (process- and GIS-based approaches). This aimed to assess yield-estimate spatial patterns and sensitivity to model selection for a wide range of combinations of water supply (i.e. irrigation and soil water storage) across New Zealand climate zones. For example, highly suitable areas for lucerne cultivation, were estimated in ∼21 thousand km2 when considering the exclusion of steep slopes, poor soil drainage and excess annual rainfall. The two crop-yield models were applied in response to 30 years of daily historical (1971–2000) weather data downscaled at 5 km resolution on suitable areas. Simulated average lucerne yields ranged from ∼4.5–28 t dry matter/ha per year. Simulations showed a distinct spatial pattern of yield decline from north to south, mainly in response to decreasing temperatures. Temporally, water limited yields were up to 4-fold more variable than under irrigation, depending on the degree of drought stress across different years. Results also unveiled systematic spatial patterns of model uncertainty quantified as yield sensitivity to model selection. For instance, simulated yields were most sensitive to model selection (6–31% of total variability, Ti) within high abiotic-stress environments (e.g. low temperature and limited water supply). Overall, soil type selection accounted for most of yield variability (58–78% Ti), being particularly important in warmer environments with variable seasonal rainfall regimes (e.g. northern regions). As expected, water supply (i.e. rain-fed or irrigated systems) was relatively more impactful on yield (8–20% Ti) for limited rainfall areas, where crops are most drought prone (e.g. east coast and central southern regions). Long-term regional scale comparisons of annual lucerne yield, between 30-year simulated distributions and point-based observations from the AgYields database, helped identify hotspots of yield overestimation. Such insights are useful to guide future research on high yield gap areas (e.g. southern colder and drier locations) and highlight key areas for model improvement (e.g. representation of multiple biotic stresses). Overall, our results provide a first gridded-model assessment of lucerne suitability and yield at national scale and quantify the share of variability explained by key climatic, management and methodological components in spatial analysis studies. These insights can inform future modelling efforts and support agricultural planning that considers the expansion of lucerne and other perennial legumes.

Effect of Deep Placement Fertilization on the Distribution of Biomass, Nutrients, and Root System Development in Potato Plants.

The study was carried out in designed pots-rhizoboxes. Root systems were evaluated using computer scanning to determine total length, root area, and root diameter. The study showed a favorable effect of deep placement of fertilizers on total yield, increasing biomass yield by 7-17% relative to surface fertilization. The largest biomass increase under the influence of deep fertilization was obtained in the case of tuber yield, in which a yield increase of 18-34% was obtained. Higher yields of potato tubers were obtained under depth fertilization compared to surface application of fertilizers. Under the influence of deep fertilization at a depth of 20 cm, the uptake of nitrogen and phosphorus by potato biomass increased by 20-21%. Increased depth of fertilization increased the proportion of nitrogen accumulated in the tubers, while in the case of phosphorus, no effect of depth on P distribution was shown. An analysis of root system parameters showed a positive effect on increases in length and total root area under deep fertilization of potato plants. Based on the study, it was found that the distribution of dry matter, nutrients, and potato root development parameters were most optimal when fertilizer granules were applied at a depth of 20 cm.

Optimizing plant type structure to adjust the temporal and spatial distribution of water consumption and promote the growth and yield formation of cotton

Global warming leads to further shortage of agricultural water resources. Understanding the water consuming characteristics of different cotton cultivars is crucial for efficient utilization of water resources and yield increasing. However, there is little evidence about the effects of cotton cultivars with different plant-type structures on yield formation and temporal and spatial distribution of water consumption. A two-year experiment was conducted at the Cotton Research Institute of the Chinese Academy of Agricultural Sciences in 2020 and 2021 to evaluate the water consumption of six cotton cultivars with different plant-type structures cotton using spatial grid method and water balance method combined with 5TE sensor. The leaf area index (LAI), biomass, yield and spatial distribution of bolls were also measured and analyzed. The results showed that the loose-type cultivars consumed more soil water than the compact-type cultivars, which was due to the higher water consumption in the 40–120 cm soil layer. The cumulative water consumption and water consumption of each soil layer (0–40 cm 40–80 cm and 80–120 cm) of different cotton cultivars had significant quadratic function relationship with LAI, and had significant linear positive correlation with biomass accumulation (aboveground biomass and underground biomass), with R2 greater than 0.8. When consuming the same amount of water, loose-type cultivars produced more biomass and larger green leaf area than compact-type cultivars. However, the yield-increasing and water-saving effects of the two plant-type structure cotton cultivars were similar, while SCRC 28 and Ji 228 have higher yield and water use efficiency (WUE), which were suitable to be popularized and planted in the cotton area of the Yellow River basin. Cotton yield was significantly negatively correlated with boll setting rate in upper canopy and water consumption in 0–40 cm soil layer, and the R respectively were − 0.82 and − 0.69; it was positively correlated with boll setting rate in lower canopy and water consumption in 80–120 cm soil layer, and the R respectively were 0.75 and 0.64. Therefore, increasing the WUE of 0–40 cm soil layer and water consumption in 80–120 cm soil layer was beneficial to high yield of cotton. By optimizing the structure of different plant types, the temporal and spatial distribution of water consumption of cotton can be adjusted, and the yield of cotton can be effectively improved. The results can provide a basis for cotton cultivar selection and precision irrigation management.

A multifaceted approach to reveal the very-fine root's response of Fagus sylvatica seedlings to different drought intensities.

How temperate trees respond to drier summers strongly depends on the drought susceptibility and the starch reserve of the very-fine roots (<0.5 mm in diameter). We performed morphological, physiological, chemical, and proteomic analyses on very-fine roots of Fagus sylvatica seedlings grown under moderate- and severe drought conditions. Moreover, to reveal the role of the starch reserves, a girdling approach was adopted to interrupt the flux of photosynthates toward the downstream sinks. Results show a seasonal sigmoidal growth pattern without evident mortality under moderate drought. After the severe-drought period, intact plants showed lower starch concentration and higher growth than those subjected to moderate drought, highlighting that very-fine roots rely on their starch reserves to resume growth. This behavior caused them to die with the onset of autumn, which was not observed under moderate drought. These findings indicated that extreme dry soil conditions are needed for significant root death in beech seedlings and that mortality mechanisms are defined within individual compartments. The girdling treatment showed that the physiological responses of very-fine roots to severe drought stress are critically related to the altered load or the reduced transport velocity of the phloem and that the changes in starch allocation critically alter the distribution of biomass. Proteomic evidence revealed that the phloem flux-dependent response was characterized by the decrease of carbon enzymes and the establishment of mechanisms to avoid the reduction of the osmotic potential. The response independent from the aboveground mainly involved the alteration of primary metabolic processes and cell wall-related enzymes.

Response to Hypersalinity of Four Halophytes Growing in Hydroponic Floating Systems: Prospects in the Phytomanagement of High Saline Wastewaters and Extreme Environments.

Hypersaline environments occur naturally worldwide in arid and semiarid regions or in artificial areas where the discharge of highly saline wastewaters, such as produced water (PW) from oil and gas industrial setups, has concentrated salt (NaCl). Halophytes can tolerate high NaCl concentrations by adopting ion extrusion and inclusion mechanisms at cell, tissue, and organ levels; however, there is still much that is not clear in the response of these plants to salinity and completely unknown issues in hypersaline conditions. Mechanisms of tolerance to saline and hypersaline conditions of four different halophytes (Suaeda fruticosa (L.) Forssk, Halocnemum strobilaceum (Pall.) M. Bieb., Juncus maritimus Lam. and Phragmites australis (Cav.) Trin. ex Steudel) were assessed by analysing growth, chlorophyll fluorescence and photosynthetic pigment parameters, nutrients, and sodium (Na) uptake and distribution in different organs. Plants were exposed to high saline (257 mM or 15 g L-1 NaCl) and extremely high or hypersaline (514, 856, and 1712 mM or 30, 50, and 100 g L-1 NaCl) salt concentrations in a hydroponic floating culture system for 28 days. The two dicotyledonous S. fruticosa and H. strobilaceum resulted in greater tolerance to hypersaline concentrations than the two monocotyledonous species J. maritimus and P. australis. Plant biomass and major cation (K, Ca, and Mg) distributions among above- and below-ground organs evidenced the osmoprotectant roles of K in the leaves of S. fruticosa, and of Ca and Mg in the leaves and stem of H. strobilaceum. In J. maritimus and P. australis the rhizome modulated the reduced uptake and translocation of nutrients and Na to shoot with increasing salinity levels. S. fruticosa and H. strobilaceum absorbed and accumulated elevated Na amounts in the aerial parts at all the NaCl doses tested, with high bioaccumulation (from 0.5 to 8.3) and translocation (1.7-16.2) factors. In the two monocotyledons, Na increased in the root and rhizome with the increasing concentration of external NaCl, dramatically reducing the growth in J. maritimus at both 50 and 100 g L-1 NaCl and compromising the survival of P. australis at 30 g L-1 NaCl and over after two weeks of treatment.

Trivial gain of downscaling in future projections of higher trophic levels in the Nordic and Barents Seas

AbstractDownscaling physical forcing from global climate models is both time consuming and labor demanding and can delay or limit the physical forcing available for regional marine ecosystem modelers. Earlier studies have shown that downscaled physics is necessary for capturing the dynamics of primary production and lower trophic levels; however, it is not clear how higher trophic levels respond to the coarse resolution physics of global models. Here, we apply the Nordic and Barents Seas Atlantis ecosystem model (NoBa) to study the consequences of using physical forcing from global climate models versus using that from regional models. The study is therefore (i) a comparison between a regional model and its driving global model to investigate the extent to which a global climate model can be used for regional ecosystem predictions and (ii) a study of the impact of future climate change in the Nordic and Barents Seas. We found that few higher trophic level species were affected by using forcing from a global versus a regional model, and there was a general agreement in future biomass trends and distribution patterns. However, the slight difference in temperature between the models dramatically impacted Northeast Arctic cod (Gadus morhua), which highlights how species projection uncertainty could arise from poor physical representation of the physical forcing, in addition to uncertainty in the ecosystem model parameterization.

Structure of settlements and resources of swifts scallop &lt;i&gt;(Chlamys swiftii&lt;/i&gt;, Bivalvia) at the coast of Primorsky Region (Japan Sea)

Current state of &lt;i&gt;Chlamys swiftii&lt;/i&gt; settlements and resources of this species in the coastal waters of Primorye (Japan Sea) are considered on the base of surveys conducted in 2007–2021. The data on spatial distribution and abundance of the scallops were obtained by methods of scuba counts at the depth &lt; 20 m. The total biomass and abundance were calculated using the Voronoi diagrams (Thiessen polygons). In total, the data were analyzed for 13457 stations located along the entire coast of Primorye from the Tumannaya/Tumen River mouth to Cape Zolotoy where 2875 scallops were sampled, weighted and measured. The average density of &lt;i&gt;Ch. Swiftii&lt;/i&gt; abundance and biomass distribution was estimated. The scallops do not form dense settlements suitable for commercial fishery. The settlements with the highest mean biomass (22.5 ± 5.0 g/m2) were concentrated in the area from Cape Povorotny to Cape Yuzhny, and the lowest biomass of the settlements was observed in Peter the Great Bay (3.7 ± 2.1 g/m2). The settlements had mosaic distribution. The total stock of the species is estimated as 1.4 . 103 t, the commercial stock – as 1.3 . 103 t. About 99 % of the total stock was concentrated at the eastern coast of Primorye in the area from Cape Povorotny to Cape Zolotoy. More regular and mass recruitment is noted for the settlements in this area, than in Peter the Great Bay. Percentage of scallops with non-commercial size varied from 1.9 to 19.0 %, by years, whereas the scallops at the age 3–7 years with shell height 70–110 mm dominated in the area from Cape Povorotny to Cape Zolotoy and those at the age 3–6 years with shell height 80–115 mm – in Peter the Great Bay. The modal age of &lt;i&gt;Ch. Swiftii&lt;/i&gt; was 4 years, the oldest specimens reached 7–12 years, by surveys.

Spatial patterns of biomass change across Finland in 2009–2015

Forest characteristics vary largely at the regional level and in smaller geographic areas in Finland. The amount of greenhouse gas emissions is related to changes in biomass and the soil type (e.g. upland soils vs. peatlands). In this paper, estimating and explaining spatial patterns of tree biomass change across Finland was the main interest. We analysed biomass changes on different soil and site types between the years 2009 and 2015 using the Finnish multi-source national forest inventory (MS-NFI) raster layers. MS-NFI method is based on combining information from satellite imagery, digital maps and national forest inventory (NFI) field data. Automatic segmentation was used to create silvicultural management and treatment units. An average biomass estimate of the segmented MS-NFI (MS–NFI–seg) map was 73.9 tons ha−1 compared to the national forest inventory estimate of 76.5 tons ha−1 in 2015. Forest soil type had a similar effect on average biomass in MS–NFI–seg and NFI data. Despite good regional and country-level results, segmentation narrowed the biomass distributions. Hence, biomass changes on segments can be considered only approximate values; also, those small differences in average biomass may accumulate when map layers from more than one time point are compared. A kappa of 0.44 was achieved for precision when comparing undisturbed and disturbed forest stands in the segmented Global Forest Change data (GFC-seg) and MS–NFI–seg map. Compared to NFI, 69% and 62% of disturbed areas were detected by GFC-seg and MS–NFI–seg, respectively. Spatially accurate map data of biomass changes on forest land improve the ability to suggest optimal management alternatives for any patch of land, e.g. in terms of climate change mitigation.

Study of Phytoplankton Biomass and Environmental Drivers in and around the Ross Sea Marine Protected Area

The Southern Ocean plays a vital role in the global climate system and the life cycle of high-latitude marine life. Phytoplankton is an important source of primary productivity in this ecosystem. Its future changes could affect Southern Ocean geochemistry, carbon export, and higher trophic organisms. To better protect Antarctica, three different marine protected areas (MPA) have been established in the Ross Sea region. Because time-continuous and regionally complete data are difficult to obtain in this region, we obtained data from ocean model outputs to understand the spatiotemporal variability of phytoplankton biomass in this region. This study explored the correlation between phytoplankton biomass and key environmental factors. Phytoplankton biomass peaks in February as temperatures rise and sea ice melts. Correlations also vary between different protected areas. The correlation between biomass, nitrate, and salinity in the Krill Research Zone (KRZ) area was significantly different from other protected areas. In addition, in the context of global warming, Antarctica lacks temperature perception. The model results show a downward trend in temperature and an increase in sea ice coverage in the western Ross Sea that other studies have also pointed to. How phytoplankton biomass will change in protected areas in the future is a question worth considering. Finally, the study simply simulates future regional trends by comparing the biomass distribution in hot years to average years. This will increase our knowledge of the polar system.

The spatial distribution characteristics of the biomass residual potential in China

Biomass energy as a kind of renewable energy would be one of the industry's future development direction. As a high energy consumption country, China is urgent need of developing the renewable energy. Understanding the distribution and components of biomass could be beneficial to guide the utilizing technologies and investment strategy of biomass residual. The comprehensive statistical methods were applied to calculate the potential biomass residual of each provinces in China. The results show that (1) Nationwide, the residues biomass of agricultural, forest, and urban waste accounted for 64.16%, 10.88%, and 24.96% of total biomass residual, respectively. The intensity of agricultural, forest, and urban waste biomass residual were 1.89, 0.32, and 0.74 PJ per km2 year, respectively. (2) The agricultural biomass residual in eastern China was more abundant than that in western China. The straw residues, agricultural processing residues, livestock manure and pruning residues from permanent orchard respectively shared 32.24%, 10.62%, 56.0%, and 1.13%. (3) The stem wood with its intensity 0.29 PJ per km2 year was major contributor of forest biomass residual (with its intensity 0.32 PJ per km2 year). The forest biomass residual in northern and southern China was larger than that in eastern and western China, but the intensity of forest biomass residual in southern China was larger than that in the other provinces. (4) The intensity of forest biomass was 0.74 PJ per km2 year, which was mainly contributed by urban greenery management outside forests (0.736 PJ per km2). The intensity of urban biomass residual in eastern and southern China was usually larger than that in northern and western China.

Cascading impacts of changes in subsidy quality on recipient ecosystem functioning.

Resource quantity and quality can differ between adjacent ecosystems, and these differences can impact subsidies exchanged between ecosystems. The quantity and quality of subsidies are rapidly changing in response to stressors associated with global environmental change, but while we have models to predict the effects of changes in subsidy quantity, we currently lack models to predict the effects of changes in subsidy quality on recipient ecosystem functioning. We developed a novel model to predict the effects of subsidy quality on recipient ecosystem biomass distribution, recycling, production, and efficiency. We parameterized the model for a case study of a riparian ecosystem subsidized by pulsed emergent aquatic insects. In this case study we focused on a common measure of subsidy quality that differs between riparian and aquatic ecosystems: the higher content of long-chain polyunsaturated fatty acids (PUFAs) in aquatic ecosystems. We analyzed how changes in the PUFA concentration of aquatic subsidies affect the dynamics in biomass stocks and functions of the riparian ecosystem. We also conducted a global sensitivity analysis to identify key drivers of subsidy impacts. Our analysis showed that subsidy quality increased the functioning of the recipient ecosystem. Recycling increased more strongly than production per unit subsidy quality increase, meaning there was a threshold where an increase in subsidy quality led to stronger effects of subsidies on recycling relative to the production of the recipient ecosystem. Our predictions were most sensitive to basal nutrient input, highlighting the relevance of recipient ecosystem nutrient levels to understanding the effects of ecosystem connections. We argue that recipient ecosystems that rely on high-quality subsidies, such as aquatic-terrestrial ecotones, are highly sensitive to changes in subsidy-recipient ecosystem connections. Our novel model unifies the subsidy hypothesis and food quality hypothesis and provides testable predictions to understand the effects of ecosystem connections on ecosystem functioning under global changes.

High-resolution spatial distribution of vegetation biomass and its environmental response on Qinghai-Tibet Plateau: Intensive grid-field survey

Due to the complexity of extremely high altitude, topography, and climate, accurately estimating regional biomass is essential yet challenging in alpine regions such as the Qinghai-Tibet Plateau (QTP). Here, we conducted an intensive grid-field survey using a matched-measured biomass dataset of 2,040 field plots on the QTP to obtain high-resolution biomass estimates and their unique response to the environment. The biomass differed significantly among different vegetation types and was highest in evergreen coniferous forests and lowest in alpine grasslands. In addition to traditional mean temperature and precipitation, ultraviolet radiation of growing season (UVGS), and the partial pressure of CO2 (PCO2) were also important factors influencing the spatial variation of vegetation biomass on the QTP. Furthermore, we simulated the spatial distribution of aboveground, belowground, and total biomass on the QTP at a 1-km resolution using the random forest algorithm, with the coefficient of determination (R2) as 0.78, 0.57, and 0.72, respectively. The new estimate of vegetation biomass on the QTP with the intensive field-survey data was 3.16 Gt, including 1.80 Gt in forests, 0.77 Gt in shrubs, 0.52 Gt in grasslands, and 0.07 Gt in deserts. Because of the unique response of biomass to the external environment, such as UVGS and PCO2, we assessed the underlying response of terrestrial ecosystems to global change more comprehensively, especially for sensitive alpine or high-latitude regions in the future. The high-resolution biomass maps may serve as support for regional carbon sink assessment and ecosystem management and conservation, and may provide important parameters for ecological process modeling.

The distribution of submerged macrophytes in response to intense solar radiation and salinity reveals hydrogen peroxide as an abiotic stress indicator

The feasible condition for submerged macrophyte growth is hard to understand as many environmental factors contribute to establishing macrophyte distribution with different intensities generating excess reactive oxygen species (ROS). Among various kinds of ROS, hydrogen peroxide (H2O2) is relatively stable and can be measured accurately. Thus, for the quantification of submerged macrophyte species, H2O2 can be used to evaluate their distribution in a lake. Submerged macrophytes, such as Potamogeton anguillanus, were abundant in Lake Shinji. The largest biomass distribution was around 1.35 m deep, under low solar radiation intensity, and nearly no biomass was found less than 0.3 m deep, where solar radiation was high. Tissue H2O2 concentrations varied in response to the diurnal photosynthetically active radiation (PAR) intensity, which was followed by antioxidant activities, though slightly delayed. Laboratory experiments were conducted with different PAR intensities or salinity concentrations. A stable level of H2O2 was maintained up to about 200 μmol m−2 s−1 of PAR for 30 days, followed by a gradual increase as PAR increased. The H2O2 concentration increased with higher salinity. A change in Chlorophyll a (Chl-a) concentration is associated with an altering H2O2 concentration, following a unique negative relationship with H2O2 concentration. If H2O2 exceeded 45 μmol/gFW, the homeostasis collapsed, and H2O2 and Chl-a significantly declined afterward. The above findings indicate that H2O2 has a negative effect on the physiological condition of the plant. The increase in H2O2 concentration was prevented by antioxidant activities, which elevated with increasing H2O2 concentration.

Optimal Placement of Biomass Distributed Generations with Intermittent Nature of Solar and Wind Renewable Sources

Optimal Placement of Biomass Distributed Generations with Intermittent Nature of Solar and Wind Renewable Sources

A Water Stress–Tolerant Pepper Rootstock Improves the Behavior of Pepper Plants under Deficit Irrigation through Root Biomass Distribution and Physiological Adaptation

The use of rootstocks tolerant to water stress in pepper crops is a complementary technique for saving irrigation water without affecting yields by means of particular rootstock physiological traits, which changes the scion’s perception stress. The present study aimed to analyze the morphological and physiological adaptation of the ‘Cuerno’ pepper cultivar grafted onto tolerant rootstock NIBER® subjected to capacitance sensor-based deficit irrigation. The stomatal conductance, relative water content and leaf water potential parameters were used to confirm the degree of crop stress. Leaf dry weight and root volume were higher in the grafted plants under the control irrigation and stress treatment conditions. Total fresh root biomass and root volume percentage of grafted plants under water stress were 24% and 33% higher, respectively, than the ungrafted plants. The grafted plants subjected to both water stress and control conditions had a higher marketable production than the ungrafted plants. The higher yields obtained using tolerant rootstocks were explained by the reduced blossom-end rot incidence.

Effects of drought stress on water content and biomass distribution in summer maize(Zea mays L.).

The resource allocation of different component organs of crops under drought stress is a strategy for the coordinated growth of crops, which also reflects the adaptability of crops to drought condition. In this study, maize variety namely 'Denghai 618', under the ventilation shed, two treatment groups of light drought (LD) and moderate drought (MD), and the same rehydration after drought are set, as well as the normal water supply for control in shed (CS). The drought experiment was conducted in the jointing-tasseling stage in 2021. The effects of different drought stress on the water content and biomass allocation of each component organ were analyzed. The results showed that (1) during the drought period, the water content of each component organ of summer maize decreased in general, but the Water content distribution ratio (WCDR) of the root increased by 1.83%- 2.35%. The WCDR of stem increased by 0.52%- 1.40%. (2) Under different drought treatments, the root biomass (RB) increased 33.94% ~ 46.09%, and fruit biomass (FB) increased 1.46% ~ 2.49%, the leaf biomass (LB) decreased by 8.2% and 1.46% respectively under LD and MD. (3) The allometric growth model constructed under sufficient water is not suitable for drought stress; the allometric exponent α under drought stress is lower than that of the CS: CS (α=1.175) > MD (α = 1.136) > LD (α = 1.048), which also indicates that the impact of existing climate change on grain yield may be underestimated. This study is helpful to understand the adaptive strategies of the coordinated growth of maize component organs under drought stress and provide a reference for the prediction of grain yield under climate change.

Exploring Energy Distribution in Ecosystems by Integrating a Classroom-Level Biological Survey

Energy and biomass distribution in the ecological sciences have long been approximated by complex, often idealized scientific models. When utilized appropriately, these models are powerful tools for students, who must organize evidence and make data-driven predictions surrounding trophic level interactions. However, the abstract nature of ecological models can present a significant challenge to students who generally require concrete experiences to make sense of complex scientific ideas. Inquiry-centered field experiences serve to bypass this barrier, providing much-needed context by leveraging student data to develop a deep conceptual understanding of foundational ecological principles.

Species composition and spatial and temporal distribution of occasional fishes in Haizhou Bay, Shandong, China.

Occasional species are often neglected in community ecology studies due to low abundance and frequence. However, they are closely related to biodiversity maintenance and marine conservation. We used index of relative importance (IRI), distribution center of gravity and Mann-Kendall trend test to elucidate the spatial and temporal distributions and changing trends of occasional fishes in Haizhou Bay based on the fishery resources survey data collected from 2013 to 2019. The occasional fishes in Haizhou Bay was identified based on IRI. Nine of the occasional species were selected to analyze the spatial distribution and interannual trends of relative biomass and occurrence frequency. The results showed that a total of 93 fish species were recorded in the multi-year survey in Haizhou Bay. Among which, 61 species had IRI<10, indicating the existence of a large number of occasional fishes in Haizhou Bay. The nine selected occasional species had distinctive spatial distribution characteristics. Erisphex pottii, Azuma emmnion, and Raja porosa were mainly distributed in the eastern part of Haizhou Bay, with a wide habitat range. Sphyraena pinguis, Coilia nasus, and Zebrias zebra were distributed in the western and southern parts, respectively. The rest species were mainly distributed in the southwestern part. In terms of interannual variation, the biomass and occurrence frequency of Coilia mystus, R. porosa, A. emmnion, and S. pinguis showed fluctuating changes, while Odontamblyopus rubicundus and Ctenotrypauchen microcephalus showed an increasing trend. The biomass and occurrence of Z. zebra, C. nasus and E. pottii gradually decreased with no catch in recent years. This study would contribute to the understanding of the spatial and temporal distribution of occasional species, and provide guidance for the conservation of occasional biological resources and species diversity, especially for the establishment of marine protected areas.

Asymmetric growth of belowground and aboveground tree organs and their architectural relationships: a review

The issue of forest trees biologically designed to withstand wind and slope stresses for improving tree anchorage and stability has been of interest to many forest ecologists for over 200 years. Asymmetry in architecture and function is a typical effect of biomechanical design. This review tried to find the architectural connectivity between belowground and aboveground organs of a tree based on a summary of observations of the asymmetric growth of crown, trunk, and root system. The asymmetrical aboveground growth is influenced by a complex interaction of tree species, age, neighborhood competition, wind, lighting, slope, and elevation. The asymmetrical belowground development is dependent on tree species, age, trunk leaning, wind, soil, and slope. Uneven water conduction, nutrient allocation, hormone content, and photosynthesis rate can influence the relationship of architectural mechanisms between the belowground and aboveground organs. The contradictory observations on the directional deformations of the root system (buttresses) reveal the particular prominence of combined effects of multiple factors. Future research should focus on the comprehensive understanding of the belowground and aboveground architectural relationships of different tree species. Our review provides novel insights into the connotations of root–shoot balance in biomass distribution of the individual plant organs.