Non-structural Carbohydrate Content Research Articles

Long-term snow alters the sensitivity of nonstructural carbohydrates of Syntrichia caninervis to snow cover: Based on a 7-year experiment.

The dynamics of nonstructural carbohydrates (NSC) profoundly affect productivity and ecological adaptability to adversity in plants. Global warming induced the frequent occurrence of extreme precipitation events that altered the winter snow pattern in deserts. However, there is a lack of understanding of how desert mosses respond to long-term snow cover change at the NSC level. Therefore, in this study, long-term (7-years) winter snow removal (-S), ambient snow (CK), and double snow (+S) experiments were set in the field to investigate the content of NSC and its component in Syntrichia Caninervis. Our results showed that changes in snow depth, snow years, and their interaction significantly affected NSC and its component of Syntrichia caninervis. Compared to snow removal, NSC, soluble sugar, and starch significantly decreased with the increasing snow depth. The ratio of soluble sugar to starch significantly increased, while NSC and soluble sugar gradually returned to the normal level with an increase in snow years. It is worth mentioning that snow removal significantly reduced the soluble sugar to starch ratio compared to ambient snow depth, whereas the double snow experiment significantly increased the ratio of soluble sugar to starch during winter. This indicated an obvious trade-off between carbon utilization and carbon storage in Syntrichia caninervis. Snow removal stimulated Syntrichia caninervis to store sufficient carbon sources by starch accumulation for its future growth, while double snow promoted its current growth by soluble sugar accumulation. The variance in decomposition showed that soil physical and chemical properties, snow cover, and their interaction explained 83% of the variation in NSC and its components, with soil and plant water content, pH, and electrical conductivity (P-WC, S-WC, S-pH, and S-EC) as significant predictors. This highlights that snow indirectly affected NSC and its component contents by changing soil physical and chemical properties; however, long-term changes in snow cover could slow down its sensitivity to snow.

Pilot Study of Sap Properties of Norway Spruce (Picea abies (L.) Karst.) Trees Used and Not Used for Sap-Feeding by Three-Toed Woodpeckers (Picoides tridactylus)

The ecophysiology of the Norway spruce (Picea abies (L.) Karst.) trees that were used by three-toed woodpeckers (TTW) (Picoides tridactylus) for their sap-feeding activities were investigated. The pilot study was conducted in southern Finland (61°15′ N, 25°00′ E). During April–June 2015, three different tree categories of Norway spruce were selected for monitoring: trees that were frequently used by the TTWs for phloem sap-feeding for several previous years; trees that were only recently used by TTWs for sap-feeding; and control trees that were not used at all for sap-feeding. Phloem sap and phloem tissue samples were frequently extracted from tree trunks and analyzed for the content and composition of nonstructural carbohydrates, phloem sap osmolality, solute, and water content, as well as for the content and composition of secondary metabolites typical for defense reactions in the phloem. Simple crown characteristics were also measured, including tree height, diameter at breast height, and their ratio (slenderness index). According to our results, the TTWs preferred Norway spruce trees that showed advanced spring phenology to feed on, as evidenced especially by the lower ratio of raffinose (typically high during the winter months) to total soluble sugars of phloem tissues as compared to non-used control trees. The lower slenderness index of the trees chosen by the TTWs indicates low canopy competition pressure with good access to light (i.e., the sun heats the trunks well in spring). There were no differences in the phloem osmolality or solute content between the used or unused control trees. The trees used by the TTWs had significantly higher concentrations of antioxidant phenolic (+)-catechins and stilbene glycosides in phloem tissue, and the stilbene content was also higher in the extracted sap. The phenolics content of the phloem tissue had a clear seasonal trend, being the highest in the early spring and lower towards the onset of the cambial growth processes. The phloem sap is rich in antioxidants and soluble sugars that are potentially beneficial for the TTWs, but more quantitative research is needed to explore the importance of the sap properties to TTWs.

Response of the fine root morphological and chemical traits of Tamarix chinensis to water and salt changes in coastal wetlands of the Yellow River Delta.

To explore the adaptation of the fine root morphology and chemical characteristics of Tamarix chinensis to water–salt heterogeneity in the groundwater–soil system of a coastal wetland zone, T. chinensis forests at different groundwater levels (high: GW1 0.54 m and GW2 0.83 m; medium: GW3 1.18 m; low: GW4 1.62 m and GW5 2.04 m) in the coastal wetland of the Yellow River Delta were researched, and the fine roots of T. chinensis standard trees were excavated. The fine roots were classified by the Pregitzer method, and the morphology, nutrients, and nonstructural carbohydrate characteristics of each order were determined. The results showed that the groundwater level had a significant indigenous effect on the soil water and salt conditions and affected the fine roots of T. chinensis. At high groundwater levels, the specific root length and specific surface area of fine roots were small, the root tissue density was high, the fine root growth rate was slow, the nutrient use efficiency was higher than at low groundwater levels, and the absorption of water increased with increasing specific surface area. With decreasing groundwater level, the N content and C/N ratio of fine roots first decreased and then increased, and the soluble sugar, starch, and nonstructural carbohydrate content of fine roots first increased and then decreased. At high and low groundwater levels, the metabolism of fine roots of T. chinensis was enhanced, and their adaptability to high salt content and low water content soil environments improved. The first- and second-order fine roots of T. chinensis were mainly responsible for water and nutrient absorption, while the higher-order (from the third to fifth orders) fine roots were primarily responsible for the transportation and storage of carbohydrates. The fine root morphology, nutrients, nonstructural carbohydrate characteristics, and other aspects of the water and salt environment heterogeneity cooperated in a synergistic response and trade-off adjustment.

Non-structural carbohydrate dynamics and growth in tomato plants grown at fluctuating light and temperature.

Fluctuations in light intensity and temperature lead to periods of asynchrony between carbon (C) supply by photosynthesis and C demand by the plant organs. Storage and remobilization of non-structural carbohydrates (NSC) are important processes that allow plants to buffer these fluctuations. We aimed to test the hypothesis that C storage and remobilization can buffer the effects of temperature and light fluctuations on growth of tomato plants. Tomato plants were grown at temperature amplitudes of 3 or 10°C (deviation around the mean of 22°C) combined with integration periods (IP) of 2 or 10 days. Temperature and light were applied in Phase (high temperature simultaneously with high light intensity, (400 μmol m–2 s–1), low temperature simultaneously with low light intensity (200 μmol m–2 s–1) or in Antiphase (high temperature with low light intensity, low temperature with high light intensity). A control treatment with constant temperature (22°C) and a constant light intensity (300 μmol m–2 s–1) was also applied. After 20 days all treatments had received the same temperature and light integral. Differences in final structural dry weight were relatively small, while NSC concentrations were highly dynamic and followed changes of light and temperature (a positive correlation with decreasing temperature and increasing light intensity). High temperature and low light intensity lead to depletion of the NSC pool, but NSC level never dropped below 8% of the plant weight and this fraction was not mobilizable. Our results suggest that growing plants under fluctuating conditions do not necessarily have detrimental effects on plant growth and may improve biomass production in plants. These findings highlight the importance in the NSC pool dynamics to buffer fluctuations of light and temperature on plant structural growth.

Prolonged phloem feeding by the spotted lanternfly, an invasive planthopper, alters resource allocation and inhibits gas exchange in grapevines.

Spotted lanternfly (Lycorma delicatula White; SLF) is a phloem‐feeding planthopper invasive to the Eastern United States that can feed on a range of wild and cultivated plant species. Since its 2014 introduction in the United States, large infestations and subsequent economic damage have been reported in cultivated grapevines, but no studies have detailed grapevine physiological responses to SLF phloem feeding. This study investigated grapevine‐SLF interactions, detailing how different infestation densities affect leaf gas exchange and end‐season concentrations of nonstructural carbohydrates and nitrogen in vegetative and perennial tissues of two Vitis species. Effects on fruit ripeness parameters and dormant bud freeze tolerance were examined, in addition to other year‐after effects. Phloem feeding by low densities (≤4 SLF shoot−1) had minimal effects, whereas greater densities (5–15 SLF shoot−1) increasingly affected carbohydrate and nitrogen dynamics in both Vitis species. Phloem feeding substantially affected starch and, to a lesser extent, total nitrogen concentrations of woody roots. Prolonged exposure strongly reduced leaf gas exchange. We conclude that intensive late‐season phloem feeding by large adult SLF population densities (≥8 SLF shoot−1) can induce carbon limitation, with the potential for negative year‐after effects in cases of severe belowground carbon depletion. This work presents novel insights into SLF‐grapevine interactions, identifies avenues of future SLF‐plant research, and assists the development of action thresholds for SLF management in vineyards.

Spatial variations and pools of non-structural carbohydrates in young Catalpa bungei undergoing different fertilization regimes.

Despite the importance of non-structural carbohydrates (NSC) for growth and survival in woody plants, we know little about whole-tree NSC storage. Here, Catalpa bungei trees fertilized using different schedules, including water and fertilizer integration, hole application, and no fertilization, were used to measure the spatial variations of sugar, starch, and NSC concentrations in the leaf, branch, stem, bark, and root. By calculating the volume of whole-tree NSC pools and the contribution of distinct organs, we were also able to compare the storage under various fertilization regimes. We found that the spatial distribution patterns of each organ undergoing different fertilization regimes were remarkably similar. Height-related increases in the sugar and NSC concentrations of the leaf and bark were observed. The concentrations of sugar and NSC in the branch did not appear to vary longitudinally or horizontally. The sugar and NSC concentrations in the stem fluctuated with height, first falling and then rising. The coarse root contained larger amounts of NSC components in comparison to fine root. Contrary to no fertilization, fertilization enhanced the distribution ratio of the leaf, branch, and stem NSC pools while decreasing the distribution ratio of the root NSC pool. Particularly, the addition of fertilizer and water significantly increased the biomass of the organs, enhancing the carbon sink of each organ and whole-tree in comparison to other fertilization regimes. Our main goal was to strengthen the empirical groundwork for comprehending the functional significance of NSC allocation and stock variations at the organ-level of C. bungei trees.

Absorptive rather than transport root decomposition drives soil carbon sequestration: A case study of Platycladus orientalis and Quercus variabilis

Root litter inputs regulate soil organic carbon stocks and turnover, which is increasingly being understood through a functional trait-based approach. Fine roots of plants are classified into absorptive and transport functional modules. However, the relative contribution of absorptive and transport roots to soil carbon sequestration and the mechanisms involved are still unclear. We conducted a 13-week container incubation experiment using soil from a C4 crop (maize) to investigate the impact of absorptive and transport root litter from Platycladus orientalis and Quercus variabilis on the turnover of new versus old soil carbon at the initial stage of root decomposition. We also measured root chemical properties, soil microbial biomass, and enzyme activity to understand how the two root functional modules regulate soil carbon sequestration differently. Absorptive roots decomposed slower than transport roots due to higher nitrogen content, a larger acid-unhydrolyzable fraction (AUF), and a lower concentration of non-structural carbohydrate (TNC) concentrations. Root litter input reduced the total soil carbon loss and increased soil carbon sequestration, with absorptive root input being more effective than transport roots. More root-derived new carbon was formed by absorptive root addition than by transport roots, likely due to the greater content of recalcitrant compounds in absorptive roots contributing to the formation of particulate organic matter. Old soil carbon loss was stimulated by the addition of transport roots and reduced by the addition of absorptive roots, suggesting a positive priming effect induced by transport roots and a negative priming effect induced by absorptive roots. Furthermore, old soil carbon loss induced by transport roots was significantly positively correlated to the presence of labile substrates and soil enzyme activities. Our results suggest that absorptive roots drive greater soil carbon sequestration than do transport roots. This occurs through more gain of new carbon and less loss of old soil carbon, emphasizing the necessity of distinguishing different root functional modules in predicting the soil carbon cycle.

EFFECT OF DIFFERENT RATIO OF PROTEIN AND CARBOHYDRATES ON THE PHYSIOLOGICAL STATE AND PRODUCTIVITY OF YOUNG BULLS

In the process of scientific work, the effect of extruded mixture of concentrates with a high content of degradable protein and non-structural carbohydrates on indicators of rumen digestion, productivity and efficiency of the dietary feed was studied.
 The objects of the study were black-and-white bulls at the age of 3-6 months. It was found that feeding them with grain mixture subjected to barothermic treatment contributed to a better growing capacity and efficiency of using nutrients in the diet. As
 a result, live weight gain in animals of the experimental group was 5.8 % higher than in the control group, and feed costs were 3.2 % lower.

The synergistic effect of hydraulic and thermal impairments accounts for the severe crown damage in Fraxinus mandshurica seedlings following the combined drought-heatwave stress

Drought combined with extreme heatwaves has been increasingly identified as the important trigger of worldwide tree mortality in the context of climate change; nonetheless, our understanding of the potential hydraulic and thermal impairments of hot droughts to trees and the subsequent post-recovery process remains limited. To investigate the response of tree water and carbon relations to drought, heatwave, and combined drought-heatwave stresses, three-year-old potted seedlings of Fraxinus mandshurica Rupr., a dominant tree species in temperate forests of northeast China, were grown under well-watered and drought-stressed conditions and exposed to a rapid, acute heatwave treatment. During the heatwave treatment with a maximum temperature exceeding 40 °C for two days, the leaf temperature of drought-stressed seedlings was, on average, 5 °C higher than that of well-watered counterparts due to less effective evaporative cooling, indicating that soil water availability influenced leaf thermoregulatory capacity during hot extremes. Consistently, more pronounced crown damage, as shown by 13 % irreversible leaf scorch, was found in seedlings under the drought-heatwave treatment relative to sole heatwave treatment, alongside the more severe stem xylem embolism and leaf electrolyte leakage. While the heatwave treatment accelerated the depletion of non-structural carbohydrates in drought-stressed seedlings, the increase of branch soluble sugar concentration in response to heatwave might be related to the requirement for maintaining hydraulic functioning via osmoregulation under high dehydration risk. The coordination between leaf stomatal conductance and total non-structural carbohydrate content during the post-heatwave recovery phase implied that plant-water relations and carbon physiology were closely coupled in coping with hot droughts. This study highlights that, under scenarios of aggravating drought co-occurring with heatwaves, tree seedlings could face a high risk of crown decline in relation to the synergistically increased hydraulic and thermal impairments.

Litter quality and decomposition responses to drought in a northeastern US deciduous forest

Even though drought impacts on tree physiology have been identified, whether drought affects leaf litter chemistry that, in turn, influences litter decay rates is still poorly understood. We compared litter quality and decomposition for two cohorts of leaves from five co-occurring seasonally deciduous tree species: Acer saccharum, Tilia americana, Quercus rubra, Quercus alba, and Ostrya virginiana. One cohort experienced a growing-season drought, and the other cohortcame from the same trees in the ensuing, post-drought growing season. Leaf litter production was greater for drought litter than post-drought litter for all five species. Specific leaf area and nitrogen concentrations were 20% greater for the drought cohort than the post-drought cohort. Concentrations of non-structural carbohydrates were about 14% greater for the drought cohort, except for greater values for post-drought A. saccharum litter. Pectin in the middle lamella of leaf litter was 31% lower for the drought cohort compared to post-drought cohort. We found few differences in litter decay rates between drought and post-drought cohorts, although Q. rubra litter had more decomposition for the post-drought cohort than the drought cohort, whereas A. saccharum litter had more decomposition for the drought cohort than the post-drought cohort. Leaf litter decay rates for the drought cohort were related to litter nitrogen and lignin concentrations, whereas decay rates for the post-drought cohort were related to litter carbohydrate concentrations. Our findings suggest that the role of drought events on seasonally deciduous forest ecosystems must recognize species-specific, idiosyncratic responses in leaf litter quality and decomposition.

Relationship among Changes in Nonstructural Carbohydrate Content, Metabolic Enzyme Activity, and Growth Rhythm in Lycoris radiata

Relationship among Changes in Nonstructural Carbohydrate Content, Metabolic Enzyme Activity, and Growth Rhythm in Lycoris radiata

Hydraulic characteristics and carbon metabolism of Haloxylon ammodendron under different water-salt content.

Drought and salt stress are important abiotic stressors that adversely affect the growth, resistance and survival of plants. Haloxylon ammodendron is a strong halophyte, and its hydraulic characteristics and carbon metabolism response to drought and salt stress under natural conditions have not been widely studied. With H. ammodendron as the research object, three sample plots with different water and salt contents (high water and high salt, medium salt in reclaimed water, low water and low salt) were selected to determine their water physiology, photosynthetic physiology, carbon physiology and growth status under different water and salt conditions. Studies have shown that drought and salinity affect the hydraulic properties of H. ammodendron, reducing the water content and water potential of assimilation branches and secondary branches and increasing the hydraulic conductivity per unit cross-sectional area of biennial shoots. Affected by drought, the content of non-structural carbohydrates (NSCs) in assimilation branches and secondary branches was significantly reduced, and the NSC content of assimilating branches was significantly higher than that in secondary branches. The transportation of NSCs to the secondary branches caused obstacles, and more accumulated in the assimilating branches. In addition, drought reduced H. ammodendron photosynthesis and carbon assimilation and limited carbon uptake, resulting in slower growth. Under the influence of drought and salinity, the anisohydric properties of H. ammodendron weakened its stomatal regulation ability and made it susceptible to water transport obstacles, but the degree of carbon limitation was relatively small.

Within-crown plasticity of hydraulic properties influence branch dieback patterns of two woody plants under experimental drought conditions

In recent year, widespread declines of Populus bolleana Lauche trees (P. bolleana, which dieback from the top down) and Haloxylon ammodendron shrubs (H. ammodendron, which dieback starting from their outer canopy) have occurred. To investigate how both intra-canopy hydraulic changes and plasticity in hydraulic properties create differences in vulnerability between these two species, we conducted a drought simulation field experiment. We analyzed branch hydraulic vulnerability, leaf water potential (Ψ), photosynthesis (A), stomatal conductance (gs), non-structural carbohydrate (NSCs) contents and morphological traits of the plants as the plants underwent a partial canopy dieback. Our results showed that: (1) the hydraulic architecture was very different between the two life forms; (2) H. ammodendron exhibited a drought tolerance response with weak stomatal control, and thus a sharp decline in Ψ while P. bolleana showed a drought avoidance response with tighter stomatal control that maintained a relatively stable Ψ; (3) the Ψ of H. ammodendron showed relative consistent symptoms of drought stress with increasing plant stature, but the Ψ of P. bolleana showed greater drought stress in higher portions of the crown; (4) prolonged drought caused P. bolleana to consume and H. ammodendron to accumulate NSCs in the branches of their upper canopy. Thus, the prolonged drought caused the shoots of the upper canopy of P. bolleana to experience greater vulnerability leading to dieback of the upper branches first, while all the twigs of the outer canopy of H. ammodendron experienced nearly identical degrees of vulnerability, and thus dieback occurred uniformly. Our results indicate that intra-canopy hydraulic change and their plasticity under drought was the main cause of the observed canopy dieback patterns in both species. However, more work is needed to further establish that hydraulic limitation as a function of plant stature was the sole mechanism for causing the divergent canopy dieback patterns.

N addition alters growth, non-structural carbohydrates, and C:N:P stoichiometry of Reaumuriasoongorica seedlings in Northwest China

Reaumuria soongorica is an important biological barrier for ecological protection in the Gobi Desert in northwestern China, where soil nitrogen availability is low. N deposition has recently increased significantly in Gobi Desert, and the responses of R. soongorica to N enrichment may become a problem for ecological restoration and protection. However, little is known about the effects of N addition on the biomass, non-structural carbohydrates (NSC), and carbon:nitrogen:phosphorus (C:N:P) stoichiometry of R. soongorica in this region. Here, we examined changes in biomass, NSC and C:N:P ratios of different organs of R. soongorica seedlings in four N addition treatments: 0 (N0), 4.6 (N1), 9.2 (N2), and 13.8 (N3) g m−2 year−1. N addition up to 9.2 g m−2 year−1 significantly increased the biomass of different organs, simultaneously increasing the belowground: aboveground ratio of R. soongorica seedlings. Root NSC concentrations significantly increased under all N addition treatments, but leaf and stem NSC concentrations only increased under the N1 and N2 addition treatments. Nitrogen addition enhanced the soluble sugar concentrations (SSC) of leaves and roots, and reduced starch concentrations (SC) of all organs. Stem and root N concentrations significantly increased under the N2 and N3 treatments, and leaf N concentrations only increased under the N3 treatment, but N addition had no significant effect on plant C and P concentrations. Leaf and stem C:N ratios decreased significantly under the N2 and N3 treatments, but root C:N decreased significantly in all N addition treatments. The N3 treatment significantly increased the N:P ratio of all organs. N addition significantly enhanced available N (AN), available P (AP) and total phosphorus (TP) in rhizosphere soil. Our results suggest that N addition alters the biomass, NSC, N concentrations, C:N and N:P ratios of all plant organs, but roots responded more strongly than stems or leaves to N addition, potentially allowing the plants to absorb more water from the arid soil in this region ensuring the survival of R. soongorica seedlings. Rhizosphere soil AP, AN and TP concentrations were important factors affecting the NSC concentrations and stoichiometric characteristics of R. soongorica.

Integrated proteomics and metabolomics analysis of rice leaves in response to rice straw return.

Straw return is crucial for the sustainable development of rice planting, but no consistent results were observed for the effect of straw return on rice growth. To investigate the response of rice leaves to rice straw return in Northeast China, two treatments were set, no straw return (S0) and rice straw return (SR). We analyzed the physiological index of rice leaves and measured differentially expressed proteins (DEPs) and differentially expressed metabolites (DEMs) levels in rice leaves by the use of proteomics and metabolomics approaches. The results showed that, compared with the S0 treatment, the SR treatment significantly decreased the dry weight of rice plants and non-structural carbohydrate contents and destroyed the chloroplast ultrastructure. In rice leaves of SR treatment, 329 DEPs were upregulated, 303 DEPs were downregulated, 44 DEMs were upregulated, and 71 DEMs were downregulated. These DEPs were mainly involved in photosynthesis and oxidative phosphorylation, and DEMs were mainly involved in alpha-linolenic acid metabolism, galactose metabolism, glycerophospholipid metabolism, pentose and gluconic acid metabolism, and other metabolic pathways. Rice straw return promoted the accumulation of scavenging substances of active oxygen and osmotic adjustment substances, such as glutathione, organic acids, amino acids, and other substances. The SR treatment reduced the photosynthetic capacity and energy production of carbon metabolism, inhibiting the growth of rice plants, while the increase of metabolites involved in defense against abiotic stress enhanced the adaptability of rice plants to straw return stress.

Soil moisture controls on the dynamics of nonstructural carbohydrate storage in Picea meyeri during the growing season

Nonstructural carbohydrate (NSC) dynamics have been suggested to be an important trait reflecting carbon balance under environmental changes. However, our understanding of NSC storage dynamics, their controls, and their responses to environmental factors remain unclear. In this study, we selected the evergreen conifer Picea meyeri at five altitudes (2040 m, 2260 m, 2440 m, 2600 m, and 2740 m a.s.l.) on Luya Mountain, North-central China. NSC concentrations in the needles, shoots, stems, and roots were measured, and the environmental variables were monitored during the growing seasons in 2018 and 2019. The results showed that the NSCs first decreased slightly and then increased gradually as altitude increased in the needles, shoots, stems, and roots. The NSC concentrations with the highest levels occurring in the needles and the lowest in the stems, whereas the shoots and roots showed intermediate concentrations. Moreover, soil moisture was the major factor influencing the dynamics of NSC storage in P. meyeri. The concentrations of soluble sugars and starch in all four organs increased with decreasing soil moisture, except for needle starch. In particular, the soluble sugars in the needles were significantly negatively correlated with air temperature, and those in the stems had a different response to soil moisture and vapor pressure deficit (VPD). Furthermore, root NSCs reserves may be important for P. meyeri to respond to low soil moisture. These findings provide new insights for understanding tree NSC allocation and the mechanism of stress resistance.

Response of leaf functional traits to precipitation change: A case study from tropical woody tree

Precipitation change is one of the most important forms of current global climate change, which will significantly influence the plant growth and development. Although numerous experiments have been conducted to investigate the effects of precipitation regulation on the plant growth and ecosystem process, the response of leaf functional traits of tropical woody species to the precipitation change is still poorly understood. In this study, three treatments, including delayed wet season (DW), wetter wet season (WW) and control check (CK), were established to examine the responses of leaf functional traits, including morphological traits, photosynthetic pigments, and non-structural carbohydrates (NSC) of the dominant woody tree, Symplocos chunii , to the simulated precipitation change in a secondary tropical forest of southern China. Our results showed that the specific leaf area (SLA), photosynthetic pigments, and NSC contents exhibited distinctly seasonal variations ( P < 0.05), but the simulated precipitation changes did not alter the leaf morphological traits (leaf length, width, or area) of S. chunii after six-year treatment. The leaf total chlorophyll contents increased observably by 83.9% in DW, and the chlorophyll b was increased by 181.5% compared to CK ( P < 0.05), while WW markedly reduced chlorophyll b content but remarkably increased carotenoid content ( P < 0.05). However, DW significantly reduced NSC contents in both dry and wet seasons. In contract, WW treatment significantly reduced leaf soluble sugar content only in the early stage of wet season, but after that, the WW did not alter the leaf soluble sugar and starch contents, even with the approach of dry season. These indicated that the precipitation change would alter the leaf photosynthetic rates thus influence the carbon assimilation, further regulate the allocation and transformation pattern of leaf NSC contents in tropical woody trees. The results suggest that the tropical woody trees may adapt to the frequent precipitation change via regulating the allocation and transformation of non-structural carbohydrates.

The mechanisms and prediction of non-structural carbohydrates accretion and depletion after mechanical wounding in slash pine (Pinus elliottii) using near-infrared reflectance spectroscopy

BackgroundThe allocation of non-structural carbohydrates (NSCs) plays a critical role in the physiology and metabolism of tree growth and survival defense. However, little is known about the allocation of NSC after continuous mechanical wounding of pine by resin tapping during tree growth.ResultsHere, we examine the NSC allocation in plant tissues after 3 year lasting resin tapping, and also investigate the use of near-infrared reflectance (NIR) spectroscopy to quantify the NSC, starch and free sugar (e.g., sucrose, glucose, and fructose) concentrations in different plant tissues of slash pine. Spectral measurements on pine needle, branch, trunk phloem, and root were obtained before starch and free sugar concentrations were measured in the laboratory. The variation of NSC, starch and free sugars in different plant tissues after resin tapping was analyzed. Partial least squares regression was applied to calibrate prediction models, models were simulated 100 times for model performance and error estimation. More NSC, starch and free sugars were stored in winter than summer both in tapped and control trees. The position of resin tapping significantly influenced the NSCs allocation in plant tissues: more NSCs were transformed into free sugars for defensive resin synthesis close to the tapping wound rather than induced distal systemic responses. Models for predicting NSC and free sugars of plant tissues showed promising results for the whole tree for fructose (R2CV = 0.72), glucose (R2CV = 0.67), NSCs (R2CV = 0.66) and starch (R2CV = 0.58) estimates based on NIR models. Models for individual plant tissues also showed reasonable predictive ability: the best model for NSCs and starch prediction was found in root. The significance multivariate correlation algorithm for variable selection significantly reduced the number of variables. Important variables were identified, including features at 1021–1290 nm, 1480, 1748, 1941, 2020, 2123 and 2355 nm, which are highly related to NSC, starch, fructose, glucose and sucrose.ConclusionsNIR spectroscopy provided a rapid and cost-effective method to monitor NSC, starch and free sugar concentrations after continuous resin tapping. It can be used for studying the trade-off between growth and production of defensive metabolites.

Reinforcer efficacy of grain for horses.

Positive reinforcement is becoming more common in horse training. Identifying effective reinforcers is critical for training success. The aim of this study was to determine relative reinforcer efficacy of different grains. Four horses learned to muzzle touch a target, after which they were tested using a progressive ratio schedule of reinforcement with different grains as the consequence. Break points were used to determine relative reinforcer efficacy of each grain and were also converted into unit price per kilocalorie to determine if caloric value impacted reinforcer efficacy. Condition 1 compared three textured grains that spanned industry-accepted standards of low to high nonstructural carbohydrate content. Condition 2 compared three pelleted grains that similarly differed in nonstructural carbohydrate content, comparable to Condition 1, but that had a different texture than those of Condition 1. Finally, Condition 3 directly compared one grain each from Conditions 1 and 2. Results showed overall little difference in reinforcer efficacy or unit price between grains but found that all grains tested functioned as reinforcers for the horses. This suggests that a range of commercially available grains can maintain behavior and therefore be used for training. We also identified possible extraexperimental factors that impact reinforcer efficacy.

Photosynthesis, Nitrogen Allocation, Non-Structural Carbohydrate Allocation, and C:N:P Stoichiometry of Ulmus elongata Seedlings Exposed to Different Light Intensities.

The leaf photosynthetic capacity, leaf N partitioning, non-structural carbohydrate content, C, N, and P contents of endangered U. elongata seedlings exposed to different light intensities were compared in this study. The most favorable light condition for the survival and growth of U. elongata seedlings in the present study was 100% full sunlight, as this induced higher Pn, PNUE, PC, PR, PB, and NSC content relative to shade-treated seedlings. PNUE, PR, PC, and PB in U. elongata seedling leaves decreased under 40% and 10% full sunlight, while PL increased, indicating that shade increased the light capture efficiency of photosystem (PS) II but decreased electron transfer from PSII to PSI. Furthermore, leaf N content increased with shade intensity, revealing an adaptive strategy for poor light environments. Additionally, the smallest leaf biomass, Pn, WUE, and CE values and C:N and C:P ratios in stems and leaves were observed under 10% full sunlight. These results indicate that seedlings growing under 40% full sunlight will benefit U. elongata conservation.