Non-structural Carbohydrate Content Research Articles

Nitrogen and Phosphorus Co-Fertilization Affects Pinus yunnanensis Seedling Distribution of Non-Structural Carbohydrates in Different Organs After Coppicing

The effects of nutritional additions on the non-structural carbohydrates (NSCs) of Pinus yunnanensis Franch. following coppicing were examined in this work. Three levels of phosphorous (P) addition, namely P0 (0 g/plant), P (2 g/plant), and P+ (4 g/plant), and two levels of nitrogen (N) additions, namely N0 (0 g/plant) and N+ (0.6 g/plant) The treatments consisted of D1 (N0P), D2 (N+P0), D3 (N0P), D4 (N+P), D5 (N0P), and D6 (N+P+), utilizing an orthogonal design to assess how these nutrients influence NSC levels and their components throughout many plant organs in P. yunnanensis. The findings showed that fertilization enhanced NSCs and their components’ contents in P. yunnanensis. P treatment greatly raised NSC levels in sprouts as well as starch (ST) content in stems and sprouts. N treatment greatly raised soluble sugar (SS) and NSC content in stems and greatly accelerated the contents of NSCs and their components in sprouts. The combined application of N and P further improved SS content in stems. Fertilization effects varied over time, with significant increases in NSC content observed at different stages: at 0 d, fertilization significantly raised NSCs and their components in needles; at 90 d, roots and stems showed increases in both NSCs and their components’ contents; at 180 d, stem ST content significantly increased; and at 270 d, NSCs and their components’ contents across all organs were significantly increased. Especially in roots, stems, and sprouts, the combined N (0.6 g/plant) and P (2.0 g/plant) treatment (D4) produced the highest NSC concentration among the treatments. This suggested that NSC formation in plants might be greatly promoted by a balanced N and P fertilization ratio acting in concert. Moreover, fertilizer, as part of a general management plan, has long-term and significant benefits on plant development, especially after coppicing, accelerating recovery, expanding growth potential, and thereby strengthening the plant’s capacity to adapt to environmental changes.

Cytokinin B-Mo-based Product Influences the Source-to-sink Dynamics and Nonstructural Carbohydrate Contents in Hydroponic Lettuce Plants

An understanding of how amendments influence the sink-to-source relationship in leafy crops can be used to optimize plant resource allocation for enhanced growth and quality. Variations in growth rates and carbon pools across individual leaves or groups of leaves at similar developmental stages allow us to comprehend plant strategies of carbon allocation and partitioning. We hypothesized that products enhancing the carbon source-to-sink relationship during leaf development can increase growth and dry matter accumulation. This project aimed to determine whether exogenous applications of a cytokinin-B-Mo-based product during the leaf development of lettuce plants impact the carbon source-to-sink relationship, thus influencing plant growth and quality. The experiment was a complete randomized design with two treatments: a negative control and the application of the product twice during the growing cycle. Each experimental unit consisted of a deep-water culture reservoir with three lettuce plants. Destructive sampling was conducted five times throughout the cycle. At each sampling time (n = 4 per experimental run), the phenological stage was determined, and measurements of root and shoot length, root and shoot dry matter, leaf length, leaf width, leaf area, chlorophyll contents, and nonstructural carbon contents were performed. These data were used to estimate growth indices. The results indicated that the cytokinin-B-Mo-based product increased the number of true unfolded leaves by 1 ± 0.4 and the overall size of the lettuce head by 9%. The treated lettuce reached marketable size 4 days earlier than that of the control treatment. Statistically significant differences were observed in shoot and root dry matter accumulation and foliar length and width at some sampling points. Some growth indices indicate an increase in leaf surface area investment and enhanced conversion efficiency of assimilates into biomass in plants treated with the product. Plants exhibiting these alterations had higher sucrose and total soluble sugar contents. There was a noticeable pattern of higher concentrations of nonstructural carbohydrates, proteins, and amino acids in the leaves compared with those in the roots across all plants and treatments. Overall, the cytokinin-B-Mo-based product appears to strengthen the source-to-sink relationship during lettuce development, resulting in a high-quality plant within a shorter timeframe.

Response of Leaf Non-Structural Carbohydrates to Elevation in Dioecious Plants, Populus cathayana and Hippophae rhamnoides

Non-structural carbohydrates (NSCs) can reflect the balance of resource allocation and trade-offs, as well as the adaptability of plants to the environment. Alterations in environmental conditions across an elevation gradient may impact the carbon balance within leaves. Nonetheless, it remains highly uncertain whether the effect of elevation on NSCs differs among species and sexes. To reveal the response patterns of leaf NSCs in dioecious plants with elevation, Populus cathayana Rehd. and Hippophae rhamnoides L., distributed at four elevations in the subalpine region of western Sichuan, China, were selected, and female and male leaves were sampled and measured for their contents of NSCs, soluble sugar, and starch. Meanwhile, the relationships of NSCs, soluble sugar, and starch with leaf nitrogen and phosphorus were analyzed. The results showed that the elevational patterns of NSCs were mainly dependent on species and were slightly affected by sex. Leaf NSCs in both sexes of P. cathayana did not exhibit significant linear changes, whereas those in H. rhamnoides increased significantly and linearly with elevation. For P. cathayana, a significant increase in leaf starch with elevation was only found in female plants and may benefit from phosphorus deficiency, as it was significantly negatively correlated with phosphorus. However, leaf soluble sugar and starch between sexes of H. rhamnoides showed similar patterns of significant increases with elevation, and they were not correlated significantly with nitrogen and phosphorus. This might be due to H. rhamnoides, which is a nitrogen-fixing plant and thereby did not show deficiencies or limitations in nitrogen and phosphorus, as shown by the decreased or unchanged elevational patterns of nitrogen/phosphorus, starch/phosphorus, and soluble sugar/phosphorus. Overall, our results emphasize that species, rather than sex, is an important factor influencing the elevational pattern of NSCs, but for specific species, such as P. cathayana, in this study, there was a divergence in the elevational response of the allocation of starch and soluble sugar between sexes, reflecting the specific adaptive strategies of different plant species or sexes in response to changes in the growing environment.

Silicon Nutrition Improves Lodging Resistance of Rice Under Dry Cultivation

Silicon (Si) has been proven to enhance the stress resistance of rice, but its effect on the lodging resistance of rice under dry cultivation (DCR) is still unclear. The purpose of this experiment is to clarify the appropriate amount of silicon fertilizer for DCR to resist lodging and to elucidate how it coordinates lodging resistance and yield. This experiment used the ‘Suigeng 18’ cultivar as the material and set six silicon fertilizers (SiO2) with dosages of 0, 15, 30, 45, 60, and 75 kg·ha−1 (Si0, Si1, Si2, Si3, Si4, Si5). Analyze the effects and key indicators of silicon on lodging resistance of DCR from the perspectives of plant weight distribution, stem structure and composition, and root architecture. The results showed that the Si3 treatment had the highest yield and the lowest lodging index (LI). Si3 increases the weight of the upper three leaves and 4–5 internodes, thereby promoting panicle weight and yield. An increase of 13.38% in 2/3PWSI (weight of the 4th–5th stems and upper three leaves/weight of the 1st–3rd stems and lower leaves) can reflect the promoting effect of silicon on stem and leaf development near the panicle. Si3 reduces the GA/IAA value, shortens the length of the second internode, and increases the diameters of the major and minor axes, thereby increasing culm thickness and section modulus (SM), achieving the effect of “short and thick”. Si3 also increases the content of silicon and non-structural carbohydrates (NSCs) in the second internode, and increases lignin and cellulose content by upregulating the expression levels of CAD7, PAL, COMT, and CesA4 genes, thereby increasing fullness and flexural strength (M), achieving “short, thick, and strong” and reducing LI. The 38.95% reduction in IFL (second internode length/fullness) reflects the positive effect of silicon on the “short, thick, and strong” stem. In the underground part, adding silicon reduces the CTK/IAA value of roots, and increases root length, root tip number, root surface area, and root weight. The key to coordinating the lodging resistance and yield of DCR with appropriate silicon dosage is to reduce the IFL in the second internode and increase 2/3 PWSI and root growth. The key to DCR and breeding is to focus on the relationship between basal internode length and fullness, as well as stem and leaf growth near the panicle.

Higher risk of hydraulic dysfunction and carbohydrate depletion of declining Larix principis-rupprechtii trees

BackgroundClimate change associated with droughts has led to widespread forest decline. Hydraulic and carbon-related performances are key physiological processes for the tolerance of trees to environmental changes, yet our current understanding of such physiological performances for forest decline is still limited. Here, we investigated the hydraulic and carbohydrate performances of healthy and declining (canopy dieback) trees in temperate larch (Larix principis-rupprechtii) plantations.ResultsRelative to healthy trees, the higher native percentage loss of xylem hydraulic conductivity and lower xylem hydraulic conductivity indicated a deterioration of the integrity of the hydraulic system in declining trees. Additionally, the comparable Huber value, intrinsic water-use efficiency, and leaf mass per area between healthy and declining trees suggest a relatively profligate water-use strategy by declining trees. Declining trees had lower nonstructural carbohydrate concentrations in leaves, branches, and twigs but higher soluble sugars concentration in fine roots than conspecific healthy trees.ConclusionsOverall, declining trees in larch plantations would be more vulnerable to drought due to the higher risk of hydraulic dysfunction and carbohydrate depletion.

Assessment of soluble carbohydrate levels in alfalfa and application of artificial intelligence technologies

The aim of this study is to assess the level of neutral detergent soluble carbohydrates of alfalfa (Medicago varia Mart.) when it is cultivated in the Central Non-Chernozem region on soddy-podzolic soil, as well as to review new methods (artificial neural networks) in solving this issue. The content of neutral detergent soluble carbohydrates (NDSC) was determined by the formula: 100 – crude protein (CP) – neutral detergent fiber (NDF) – crude ash (CA) – crude fat (CF). Data on the content of the components of the formula were used to determine levels of NDSC in four alfalfa varieties at the following growth phases: branching, beginning of budding, budding and flowering. Concentrations of NDSC decreased as the plants matured and were (% per dry matter on average for all varieties): at branching – 39.4, at the beginning of budding – 35.5, at budding – 32.7, and at flowering – 26.6. In cooler and more humid conditions of vegetation, the content of CP and NDF was lower, and therefore the level of NDSC was higher and amounted to 36.1% in the budding phase. There is a strong negative correlation between NDSC and the contents of the sum of NDF + CP and NDF alone. The correlation coefficients were 0.96 and 0.90, respectively. Among the components of neutral detergent carbohydrates, the content of non-structural carbohydrates and their proportion were determined. Both indicators decreased with the growth of the plants. Methods for the determination of protein, fiber and crude ash can be based on the use of infrared analyzers. It is important to build appropriate calibration models that are non-linear in nature. Advanced methods for building calibration models include artificial intelligence methods, namely artificial neural networks. Such a methodology can be used, for example, to recommend the optimal period of grass cutting.

Leaf nonstructural carbohydrate residence time, not concentration, correlates with leaf functional traits following theleaf economic spectrum in woody plants.

Nonstructural carbohydrate (NSC) concentrations might reflect the strategies described in the leaf economic spectrum (LES) due to their dependence on photosynthesis and respiration. We examined if NSC concentrations correlate with leaf structure, chemistry, and physiology traits for 114 species from 19 sites and 5 biomes around the globe. Total leaf NSC concentrations varied greatly from 16 to 199 mg g-1 dry mass and were mostly independent of leaf gas exchange and the LES traits. By contrast, leaf NSC residence time was shorter in species with higher rates of photosynthesis, following the fast-slow strategies in the LES. An average leaf held an amount of NSCs that could sustain one night of leaf respiration and could be replenished in just a few hours of photosynthesis under saturating light, indicating that most daily carbon gain is exported. Our results suggest that NSC export is clearly linked to the economics of return on resource investment.

Source-sink manipulations through shading, crop load and water deficit affect plant morphogenesis and carbon sink priorities leading to contrasted plant carbon status in grapevine.

Shading, water deficit, and crop load shape plant development in a very plastic way. They directly influence the plant's carbon supply and demand to and from the different organs via metabolic, hydraulic and hormonal mechanisms. However, how the multiple environmental factors combine through these mechanisms and how they interplay with carbon status, vegetative and reproductive development and carbon assimilation of the plant needs to be investigated in the context of current climatic and technological constraints. With this aim, two experiments were conducted on potted grapevines, subjected to ten combinations of treatments. Axis organogenesis, berry characteristics at harvest (weight, number and total soluble content) and a series of leaf traits (gas exchanges, non-structural carbohydrate contents, water potential and SPAD values) were measured. Grapevine development showed different responses corresponding to different sink priorities: under shade, vegetative development was maintained at the expense of berries, whereas under high crop load and water deficit, berry growth was the priority sink. These responses were accompanied by changes in the specific leaf area in agreement with the shade avoidance syndrome. These different strategies affected the plant carbon status as estimated through the starch content in leaves. Leaf starch content was not affected by shade, while it decreased under water deficit and crop load conditions. Carbon assimilation was decreased under water deficit, low crop load and shading conditions. Hydraulic properties and leaf nitrogen content correlated withthis decrease while plant carbon status has a very low impact. Finally, no major interaction between the different types of constraints were observed both on morphological and functional variables. Depending on the type of abiotic constraints, grapevine exhibits specific morphogenetic responses at plant and leaf levels. The absence of interaction between the different constraints showed that grapevine is able to exhibit independent responses to shade and water deficit. This result is of major importance to further design new agricultural systems facing multiple abiotic constraints, such as those in agroforestery and agrivolatic system.

Coordination of Carbon and Nitrogen Metabolism Through Well-Timed Mid-Stage Nitrogen Compensation in Japonica Super Rice.

The carbon and nitrogen (N) metabolism of rice under different mid-stage N compensation timings is unclear. Two Japonica super rice cultivars were examined under four N compensation timings (N1-N3: N compensation at mid-tillering, panicle initiation, and spikelet differentiation. N0: no N compensation) and CK with no N application. Mid-stage N compensation increased the N concentrations of various tissues, and N2 showed the highest plant N uptake at both the heading stage, maturity, and the grain filling period. Among the treatments, N2 showed the highest N utilization efficiency. With delayed compensation timing, there was a gradual decrease in soluble sugar and starch concentrations in each tissue, accompanied by a decline in the non-structural carbohydrate (NSC) concentration. Specifically, N2 treatment exhibited the highest NSC accumulation and the remobilized NSC reserve, but NSCs per spikelet decreased with delayed compensation timing. The highest yield was also obtained with N2, exhibiting a 4.5% increase compared to the N0 treatment, primarily due to an improvement in spikelets per panicle. Conclusively, N compensation at the panicle initiation stage is a reasonable N management strategy that can coordinate the improvement of carbon and N metabolism, enhance N accumulation with efficient utilization and NSC accumulation, and ultimately increase the yield.

Impacts of elevated CO2 and partial defoliation on mineral element composition in rice.

This study explores how elevated CO2 concentration may alter the source-sink dynamics in rice by providing additional carbon for photosynthesis, thereby affecting nutrient absorption and distribution. A free-air CO2 enrichment experiment was conducted on a japonica cultivar Wuyunjing 27 in 2017 and 2018 growing seasons. The plants were exposed to ambient and elevated CO2 level (increased by 200 μmol·mol-1) and two source-sink manipulation treatments (control with no leaf cutting and cutting off the top three leaves at heading). The elevated CO2 significantly increased the above-ground biomass and the straw non-structural carbohydrate concentration by an average of 19.3% and 12.5%, respectively. Significant changes in the concentrations of N, S, Fe, and Zn in straw were noted under elevated CO2, with average decreases by 7.1, 7.2, 11.6, and 10.1%, respectively. The exposure to elevated CO2 significantly enhanced the elements accumulation, yet it had minimal impact on their distribution across different organs. When compared to intact rice, removing the top three leaves at heading reduced the above-ground biomass by 36.8% and the straw non-structural carbohydrate content by 44.8%. Leaf-cutting generally increased the concentration of elements in stem, leaf, and grain, likely due to a concentration effect from reduced biomass and carbohydrate accumulation. Leaf-cutting reduced element accumulation and shifted element allocation in rice organs. It increased the proportion of elements in stems while reduced their presence in leaves and grains. Our study suggests that a dilution effect may cause a decrease in mineral elements concentrations under elevated CO2 because of the increase in biomass and carbohydrates.

Internal physiological drivers of leaf development in trees: Understanding the relationship between non‐structural carbohydrates and leaf phenology

Abstract Plant phenology is crucial for understanding plant growth and climate feedback. It affects canopy structure, surface albedo, and carbon and water fluxes. While the influence of environmental factors on phenology is well‐documented, the role of plant intrinsic factors, particularly internal physiological processes and their interaction with external conditions, has received less attention. Non‐structural carbohydrates (NSC), which include sugars and starch essential for growth, metabolism and osmotic regulation, serve as indicators of carbon availability in plants. NSC levels reflect the carbon balance between photosynthesis (source activity) and the demands of growth and respiration (sink activity), making them key physiological traits that potentially influence phenology during critical periods such as spring leaf‐out and autumn leaf senescence. However, the connections between NSC concentrations in various organs and phenological events are poorly understood. This review synthesizes current research on the relationship between leaf phenology and NSC dynamics. We qualitatively delineate seasonal NSC variations in deciduous and evergreen trees and propose testable hypotheses about how NSC may interact with phenological stages such as bud break and leaf senescence. We also discuss how seasonal variations in NSC levels, align with existing conceptual models of carbon allocation. Accurate characterization and simulation of NSC dynamics are crucial and should be incorporated into carbon allocation models. By comparing and reviewing the development of carbon allocation models, we highlight the shortcomings in current methodologies and recommend directions to address these gaps in future research. Understanding the relationship between NSC, source–sink relationships, and leaf phenology poses challenges due to the difficulty of characterizing NSC dynamics with high temporal resolution. We advocate for a multi‐scale approach that combines various methods, which include deepening our mechanistic understanding through manipulative experiments, integrating carbon sink and source data from multiple observational networks with carbon allocation models to better characterize the NSC dynamics, and quantifying the spatial pattern and temporal trends of the NSC‐phenology relationship using remote sensing and modelling. This will enhance our comprehension of how NSC dynamics impact leaf phenology across different scales and environments. Read the free Plain Language Summary for this article on the Journal blog.

Analyzing the impact of phosphorous and nitrogen on Castanopsis sclerophylla early growth stages

Plant growth elements, particularly nitrogen (N) and phosphorus (P) are vital for their growth and development, particularly for understory vegetation and their excess limits the net productivity of terrestrial ecosystems. This study focuses on the understory vegetation responds and adaptation to key essential nutrients under changing climate scenarios in subtropical evergreen broad-leaved forests, still needs research attention. this, we set up an experiment taking four treatments in a 50-year-old Castanopsis sclerophylla secondary forest under (a) control (CK), (b) N, (c) P, and (d) combined N and P addition, applied to natural forest regeneration seedlings of C. sclerophylla attained similar growth parameters of diameter of 3 cm and 10 cm height. In addition, carbon, N, P, and non-structural carbohydrates (NSC) were determined through the anthrone colorimetric approach in different parts of seedlings. Results show that the combined N + P application enhanced the N and P by 14.48 %−140.55 % in the seedlings in both dry and wet seasons, respectively. However, during wet season, the content of NSC in the plant leaves significantly exceeded under P addition. Remarkably, CK showed increased P in the growing season but lower during the dry season. Furthermore, the root starch content of seedlings showed a significant increase under the application of N and P compared to combined N + P, ranging between 45.60 % and 58.70 %. Overall, the plant growth is attributed to N and P intake. The nutrient addition and seasonal variations have a coupled effect on seedling growth as proved in the in the natural open forest experiment. The study outcomes emphasize that the alterations in NSC allocation in the roots and leaves of C. sclerophylla seedlings under N + P addition could enhance their adaptation to future global climate changes, drought conditions, and high N concentrations.

Impacts of groundwater depth and tree age on the non-structural carbohydrates of Haloxylon ammodendron

Nonstructural carbohydrates (NSC) are important substrates for plant growth and metabolism, and their concentration reflects the plant's ability to adapt to environmental changes. Although the response of NSC to changes in water availability has been extensively studied, it is still not fully understood whether this response is modulated by tree ages and organs. This study investigates Haloxylon ammodendron (C.A. Mey.) Bunge ex Fenzl, the dominant species in the Gurbantunggut Desert in the Uyghur Autonomous Region of China. Utilizing the natural topographic conditions characterized by a gradual increase in groundwater depth from the desert edge to the hinterland, we collected samples of different age classes of H. ammodendron along a groundwater depth gradient of 3, 7, 10, and 14 m. We measured the total concentrations of non-structural carbohydrates (NSC) and its components soluble sugar (SS) and starch (ST) in the assimilative twigs and stems. The results showed that the assimilative twigs of H. ammodendron exhibited higher NSC concentrations at the site with the deepest groundwater, while the other three sites showed similar NSC concentrations. Furthermore, as groundwater depth increased, the concentrations of SS in the assimilative twigs increased, whereas ST concentrations decreased. Similarly, the concentrations of SS in the stems also increased at sites with deeper groundwater. The NSC concentrations in the assimilative twigs were significantly affected by groundwater depth, while variations in stem NSC were primarily driven by plant age. In younger trees, higher soluble sugars concentrations in the stem may enhance water transport efficiency, whereas older trees tend to store more NSC to alleviate drought stress. Overall, elevated nonstructural carbohydrate concentrations contributed to greater drought resilience in H. ammodendron. These results suggest that different age classes of H. ammodendron exhibit distinct physiological responses to decreasing groundwater depth. The varying requirements for soluble sugars and starch in H. ammodendron help to partially mitigate the adverse effects of reduced groundwater accessibility. These findings provide important insights into the physiological adaptations of H. ammodendron in arid environments and offer a scientific basis for future ecological restoration and management strategies.

Effects of Biochar and Nitrogen Fertilizer Application Ratio on Leaf Physiology and Soil Characteristics of Bambusa tuldoides ‘Swolleninternode’

As one of the main bamboo species in coastal sandy land protection forests, Bambusa tuldoides ‘Swolleninternode’ can effectively improve the structure of forest tree species, increase the diversity of tree species and enhance the protection efficiency. However, research on the cultivation and utilization of B. tuldoides is still relatively scarce. Therefore, in this study, B. tuldoides was used as the research object. By applying biochar and nitrogen fertilizer, the effects of different biochar and nitrogen fertilizer ratios on the physiology and soil characteristics of bamboo were analyzed, and the optimal ratio scheme was identified. The results showed that the ratio of the T5 (A2B2C3) treatment had the best effect on the total chlorophyll, non-structural carbohydrate and nutrient contents of B. tuldoides leaves, and the contents under treatments was generally higher than under the control, CK. The activities of soil invertase, nitrate reductase and nitrite reductase were significantly increased under biochar treatment, and the effects of the T5 treatment were the best. The results of principal component analysis showed that the absolute values of the coefficient of leaf potassium, phosphorus content and soil total nitrogen were larger and more important, and the comprehensive evaluation of the T5 treatment was the highest.

Animal behaviour and dietary preference of dairy cows grazing binary and diverse pastures under the leaf regrowth stage defoliation criterion

In New Zealand, intensively managed pasture-based dairy systems rely on binary pastures mostly comprised of Lolium perenne L. and Trifolium repens L.. More frequent and extreme climatic events have been negatively affecting the persistency and production of these pastures, which now present increased seasonality, with marked peaks and troughs of production throughout the year. Diversification of plant species offers a solution to deal with increased seasonality. However, little is known about animal behaviour and dietary preferences of dairy cows grazing diverse pastures. The present study aimed to assess the grazing preferences of dairy cows when unrestrictedly offered binary (L. perenne and T. repens; Bi) and diverse pastures (L. perenne, Bromus valdivianus Phil., Dactylis glomerata L. and T. repens; Mix) subjected to three different leaf regrowth stage (LS) defoliation criteria. Secondarily, the study aimed to determine the main plant-related drivers for any potential animal preference. The treatments were MixLp (defoliated at L. perenne LS), BiLp (defoliated every time MixLp was defoliated), MixBv (defoliated at B. valdivianus LS) and BiBv (defoliated every time MixBv was defoliated), MixDg (defoliated at D. glomerata LS) and BiDg (defoliated every time MixDg was defoliated). Dairy cattle were evaluated over five agricultural seasons. The response variables were grazing time and location, bite rate, animal behavioural activity, pre-grazing herbage mass, undisturbed sward height, lamina:stem ratio, crude protein, metabolisable energy, organic matter digestibility, non-structural carbohydrates, neutral detergent fibre and lignin. Where significant differences were found, binary pastures presented lower sward height and higher non-structural carbohydrate content in comparison to the diverse pastures under the same LS defoliation criteria. However, no significant differences were found in the percentage of time that cows spent grazing both pastures. Season was the greatest contributor to the proportion variation found in all response variables, with values ranging from 47.55 % up to 88.77 %. In winter and spring, cows modulated their grazing behaviour (proportional time spent grazing, ruminating, or idling), investing more time actively grazing pastures under L. perenne LS interval of defoliation (2.5–3.0 LS), the criterion which resulted in shorter grazing rotations. This study allowed us to understand the suitability of diverse pastures from an animal perspective, and highlighted that independent of the pasture type, the positive productive and nutritional effects of defoliation management based on the LS may also extend themselves to positive outcomes in animal preference, interpreted as the percentage of time dairy cows spend grazing rather than ruminating or idling across and within seasons.

Water, not carbon, drives drought-constraints on stem terpene defense against simulated bark beetle attack in Pinus edulis.

Drought predisposes forest trees to bark beetle-induced mortality, but the physiological mechanisms remain unclear. While drought-induced water and carbon limitations have been implicated in defensive failure and tree susceptibility, evidence demonstrating how these factors interact is scarce. We withheld water from mature, potted Pinus edulis and subsequently applied a double-stem girdle to inhibit carbohydrate transport from the crown and roots. Within this isolated segment we then elicited a defense response by inoculating trees with a bark beetle-fungal symbiont (Ophiostoma sp.). We quantified local mono- and sesquiterpenes (MST), nonstructural carbohydrates (NSC), and pressure potential of the inner bark. Both drought-stressed and watered trees had similar NSC concentrations just before inoculation and depleted NSC similarly following inoculation, yet MST induction (i.e. increased concentration and altered composition) was constrained only in drought-stressed trees. Thus, NSC consumption was largely unrelated to de novo MST synthesis. Instead, stoichiometric calculations show that induction originated largely from stored resin. Watered trees experiencing higher pressure potentials consistently induced higher MST concentrations. We demonstrate the importance of preformed resin toward an induced MST response in a semi-arid conifer where drought-constraints on defense occurred through biophysical limitations (i.e. reduced turgor hindering resin transport) rather than through substrate limitation.

Halophytic succulence is a driver of the leaf non-structural carbohydrate contents in plants in the arid and hyper-arid deserts of northwestern China.

Non-structural carbohydrates (NSC), primarily sugars and starch, play a crucial role in plant metabolic processes and a plant's ability to tolerate and recover from drought stress. Despite their importance, our understanding of NSC characteristics in the leaves of plants that thrive in hyper-arid and saline environments remains limited. To investigate the variations in leaf NSC across different species and spatial scales, and to explore their possible causes, we collected 488 leaf samples from 49 native plant species at 115 sites in the desert area of northwestern China. The contents of soluble sugars (SS), starch, and total NSC were then determined. The average contents of SS, starch, and total NSC were 26.99, 60.28, and 87.27mg g-1 respectively, which are much lower than those reported for Chinese forest plants and global terrestrial plants. Herbaceous and woody plants had similar NSC levels. In contrast, succulent halophytes, a key component of desert flora, showed significantly lower leaf SS and total NSC contents than non-succulent plants. We observed a strong negative correlation between leaf succulence and SS content, suggesting a role of halophytic succulence in driving multi-species NSC pools. Environmental factors explained a minor portion of the spatial variation in leaf NSC, possibly due to the narrow climatic variation in the study area, and soil properties, particularly soil salinity, emerged as more significant contributors. Our findings increase the understanding of plant adaptation to drought and salt stress, emphasizing the crucial role of halophytic succulence in shaping the intricate dynamics of leaf NSC across diverse plant species in arid and hyper-arid environments.

Combined transcriptome and physiological analysis reveals exogenous sucrose enhances photosynthesis and source capacity in foxtail millet

Foxtail millet (Setaria italica (L.) P. Beauv.) is an environmentally friendly crop that meets the current requirements of international food security and is widely accepted as a photosynthesis research model. However, whether exogenous sucrose treatment has a positive effect on foxtail millet growth remains unknown. Here, we employed physiological and molecular approaches to identify photosynthesis and source capacity associated with exogenous sucrose during the growth of Jingu 21 seedlings. RNA-seq analysis showed that some differentially expressed genes (DEGs) related to photosynthesis and carotenoid biosynthesis were induced by exogenous sucrose and that most of these genes were up-regulated. An increase in gas exchange parameters, chlorophyll content, and chlorophyll fluorescence of Jingu 21 was noted after exogenous sucrose addition. Furthermore, exogenous sucrose up-regulated genes encoding sucrose and hexose transporters and enhanced starch and sucrose metabolism. More DEGs were up-regulated by sucrose, the nonstructural carbohydrate (NSC) content in the leaves increased and energy metabolism and sucrose loading subsequently improved, ultimately enhancing photosynthesis under normal and dark conditions. Further analysis revealed that WRKYs, ERFs, HY5, RAP2, and ABI5 could be key transcription factors involved in growth regulation. These results indicate that exogenous sucrose affects the normal photosynthetic performance of foxtail millet by increasing NSC transport and loading. They improve our understanding of the molecular mechanisms of the effects of exogenous sucrose on photosynthesis in foxtail millet, providing an effective measure to enhance source–sink relationships and improve yield.

Megafire smoke exposure jeopardizes tree carbohydrate reserves and yield.

The global incidence of megafires is on the rise, leading to extensive areas being shrouded in dense smoke for prolonged periods, spanning days or weeks1. Here, by integrating long-term regional observations of non-structural carbohydrate content in trees across California's Central Valley with spatiotemporal satellite data, we present compelling evidence that dense smoke plumes negatively impact carbohydrate stores in three tree species: Prunus dulcis, Pistacia vera and Juglans regia. Our findings show that the presence of smoke causes a significant decrease in total non-structural carbohydrates, with reductions in the accumulation of both soluble sugar and starch reserves. This decline in carbohydrate levels persists through the trees' dormancy period into the next season's bloom, culminating in a reduced yield. Our results highlight a previously unrecognized wildfire threat that could affect plant health and ecosystem stability in both agricultural and natural environments.

Adjustment of storage capacity for non-structural carbohydrates in response to limited water availability in two temperate woody species.

Reserves of non-structural carbohydrates (NSC) stored in living cells are essential for drought tolerance of trees. However, little is known about the phenotypic plasticity of living storage compartments (SC) and their interactions with NSC reserves under changing water availability. Here, we examined adjustments of SC and NSC reserves in stems and roots of seedlings of two temperate tree species, Acer negundo L. and Betula pendula Roth., cultivated under different substrate water availability. We found that relative contents of soluble NSC, starch and total NSC increased with decreasing water availability in stems of both species, and similar tendencies were also observed in roots of A. negundo. In the roots of B. pendula, soluble NSC contents decreased along with the decreasing water availability, possibly due to phloem decoupling or NSC translocation to shoots. Despite the contrast in organ responses, NSC contents (namely starch) positively correlated with proportions of total organ SC. Individual types of SC showed markedly distinct plasticity upon decreasing water availability, suggesting that water availability changes the partitioning of organ storage capacity. We found an increasing contribution of parenchyma-rich bark to the total organ NSC storage capacity under decreasing water availability. However, xylem SC showed substantially greater plasticity than those in bark. Axial storage cells, namely living fibers in A. negundo, responded more sensitively to decreasing water availability than radial parenchyma. Our results demonstrate that drought-induced changes in carbon balance affect the organ storage capacity provided by living cells, whose proportions are sensitively coordinated along with changing NSC reserves.