Nonstructural Carbohydrate Composition Research Articles

Strong culm: a crucial trait for developing next-generation climate-resilient rice lines.

Lodging, a phenomenon characterized by the bending or breaking of rice plants, poses substantial constraints on productivity, particularly during the harvesting phase in regions susceptible to strong winds. The rice strong culm trait is influenced by the intricate interplay of genetic, physiological, epigenetic, and environmental factors. Stem architecture, encompassing morphological and anatomical attributes, alongside the composition of both structural and non-structural carbohydrates, emerges as a critical determinant of lodging resistance. The adaptive response of the rice culm to various biotic and abiotic environmental factors further modulates the propensity for lodging. Advancements in next-generation sequencing technologies have expedited the genetic dissection of lodging resistance, enabling the identification of pertinent genes, quantitative trait loci, and novel alleles. Concurrently, contemporary breeding strategies, ranging from biparental approaches to more sophisticated methods such as multi-parent-based breeding, gene pyramiding, genomic selection, genome-wide association studies, and haplotype-based breeding, offer perspectives on the genetic underpinnings of culm strength. This review comprehensively delves into physiological attributes, culm histology, epigenetic determinants, and gene expression profiles associated with lodging resistance, with a specialized focus on leveraging next-generation sequencing for candidate gene discovery.

The composition of non-structural carbohydrates affects the respiration and morphology of tree fine roots in Japan Alps

Non-structural carbohydrates (NSC), such as soluble sugars and starch, are important drivers of physiological function and survival in woody plants. The soluble sugar and starch in the organs of woody plants might affect their resource acquisition, but little is known about their direct association with the fine root physiological function. Here, we aimed to quantify the storage of soluble sugar and starch in the fine roots of two woody species, found under the alpine treeline, namely, Maries' fir (Abies mariesii) and Erman's birch (Betula ermanii). We also set out to identify the relationship between each NSC and both fine root respiration and morphology of the plants. To this end, the concentrations of soluble sugar and starch, root respiration rate, and specific root length (SRL) were measured in three root diameter classes: <0.5, 0.5–1.0, and 1.0–2.0 mm. In both species, we found that the sugar concentration of <0.5 mm roots was lower than that in both 0.5–1.0 and 1.0–2.0 mm roots, whereas there were no clear differences in starch concentration among the three classes. Additionally, our results showed that the sugar concentration was negatively correlated with the root respiration rate and SRL, whereas starch concentration did not show any correlation with these factors. Altogether, these findings suggest that the soluble sugar in fine roots can act as a direct source of energy for the roots to aid soil resource acquisition, whereas the starch can serve as an indirect, longer-term storage reservoir. Such distinct differences in the storage and function of soluble sugar and starch in fine roots are likely to improve our understanding of the sink-size of each process in terms of carbon consumption for root respiration and root morphology for soil resource acquisition.

Age-related differences in physiological and metabolic responses of Pleione aurita (Orchidaceae) pseudobulbs to drought stress and recovery

The pseudobulb is a storage organ for water and nutrients that plays a crucial role in the growth and survival of epiphytic orchids. However, the role of water and metabolites in pseudobulb during adaptation to environmental stress are rarely detected through control experiments. In the present study, water-related physiological traits and metabolite changes in the pseudobulbs at the flowering stage and full leaf expansion stage for Pleione aurita were investigated after drought stress and recovery treatments. We found that the composition of non-structural carbohydrates (starch vs. soluble sugar) varied over the lifetime of pseudobulbs, and older pseudobulbs stored more water, whereas younger pseudobulbs stored more dry matter. When plants were subjected to drought stress and subsequent recovery, multiple metabolites in the pseudobulbs including non-structural carbohydrates, flavonoids, phenolic acids, as well as amino acids and their derivatives responded positively to these water level fluctuations. For those metabolites that differently accumulated in both stress and recovery processes, old pseudobulbs contained a higher number of these key metabolites than did the connected younger pseudobulbs. In addition, young and old pseudobulbs use different metabolic pathways to both respond and recover to drought. These results indicate that orchid pseudobulbs cope with water level fluctuations by mobilizing metabolite reserves and that pseudobulbs of different ages exhibit different physiological and metabolic responses to drought stress. These findings broadens our understanding of the role pseudobulbs play in the survival of orchids growing in epiphytic habitats.

Dynamic variation of non-structural carbohydrates in branches and leaves of temperate broad-leaved tree species over a complete life history

The composition of non-structural carbohydrates (NSC), one of the photosynthetic products of plants, reflects the survival strategy of a plant. Although several studies have investigated variation of NSC content in woody plants over a set time scale, few studies have considered the dynamic variation of NSC over a continuous life history. In this study, the leaves, new twigs, and old branches of seven temperate broad-leaved tree species (diffuse-porous species:Betula platyphylla,Betula costata,Tilia amurensis,Acer pictumsubsp.mono; ring-porous species:Ulmus davidianavar.japonica,Ulmus laciniata,Fraxinus mandshurica) were observed at three life history stages (seedling, sapling, and mature tree) to measure the dynamic changes of NSC and its influencing factors throughout the entire life cycles of these species. The results showed that life history, wood type, and environmental factors (soil nitrogen and phosphorus content, soil pH) significantly affected the NSC content in leaves and branches (including both new twigs and old branches). As plants grew, the NSC content in the leaves and branches generally showed an upward trend, meaning the total non-structural carbohydrate (TNC) content and soluble sugar (SS) content increased significantly, and the starch (ST) content was relatively stable. Lastly, there was no significant difference in NSC content between the canopy layers of mature trees. This indicates that the influence of life stage on NSC content in leaves and branches of plants may be dominated by genetics instead of being regulated by light factors.

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.

Biomass allocation and seasonal non-structural carbohydrate dynamics do not explain the success of tall forbs in short alpine grassland

The majority of alpine plants are of small stature. Through their small size alpine plants are decoupled from the free atmospheric circulation and accumulate solar heat. However, a few alpine species do not follow that “rule” and protrude with their aboveground structures from the microclimatic shelter of the main canopy boundary layer. We aim at explaining the phenomenon of being tall by exploring the biomass production and carbon relations of four pairs of small and tall phylogenetically related taxa in alpine grassland. We compared species and stature-specific biomass allocation, shifts in non-structural carbohydrate (NSC) concentrations in different tissues throughout the season, and we used 13C labels to track carbon transfer from leaves to belowground structures. Small and tall herbs did not differ in their above- to belowground biomass allocation. The NSC composition (starch, fructan, simple sugars) and allocation did not show a stature-specific pattern, except for higher concentrations of simple sugars in tall species during their extended shoot growth. In relative terms, tall species had higher NSC pools in rhizomes, whereas small species had higher NSC pools in roots. Our findings do not place tall alpine forbs in an exceptional category in terms of biomass allocation and carbohydrate storage. The tall versus small stature of the examined herbs does not seem to be associated with specific adjustments in carbon relations. 13C pulse labelling revealed early C autonomy in young, unfolding leaves of the tall species, which are thus independent of the carbon reserves in the massive belowground organs.

Application of ATR-FTIR spectroscopy for profiling of non-structural carbohydrates in onion (Allium cepa L.) bulbs

Qualitative and quantitative composition of non-structural carbohydrates comprising glucose, fructose, sucrose and fructooligosaccharides (FOS) is one of the key determinants of market suitability, storability and technological processability of onions. To develop a cost-effective and rapid tool for carbohydrate profiling, applicability of attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy of onion juice was investigated with special regard to FOS patterns. As reference, detailed carbohydrate profiles of onion juices were generated by high-performance liquid chromatography coupled with evaporative light scattering detection (HPLC-ELSD).Hierarchical cluster analysis (HCA) of ATR-FTIR spectra was successfully applied for classifying onions into fresh market, storage and dehydrator type according to HPLC-ELSD profiles.A bootstrapping method for automatized test-set validation by projection to latent structures (PLS) algorithms using HPLC and ATR-FTIR spectroscopy data was developed. Model statistics showed promising perspectives for reliable quantification of individual saccharides and sum parameters. The presented methodology allows estimating the nutritional and pre-biotic value directly during cultivation and processing.

Assessing the nitrogen status of almond trees by visible-to-shortwave infrared reflectance spectroscopy of carbohydrates

Precise nitrogen (N) fertilization requires new indices of plants’ nutritional status. Non-structural carbohydrates (NSC) are the energetic currency of plants and can, thus, serve as a physiological indicator for their condition. Nevertheless, only a few records exist about NSC composition and allocation in crops, and their relationship with N uptake and the current methods to detect NSC compositions in plants are cumbersome and expensive, which limits their use. The current work aimed to associate the nutritional status of almond trees with the carbohydrate compositions in their roots, branches, and leaves by a high-throughput technique. We found that low N availability forces trees to allocate carbohydrates to their roots. High N availability, on the other hand, promoted above-ground vegetative growth, and minimized carbohydrate storage in the leaves. These observations implied that carbohydrate distribution could, indeed, serve as an indication of the nutritional status of the trees. To measure NSC content efficiently, we attempted to quantify soluble carbohydrates and starch in dried and powdered tissues by visible-to-shortwave infrared (VIS-NIR-SWIR; 350–2500 nm) reflectance spectroscopy, which is an inexpensive, safe, and non-destructive technique. We applied several multivariate statistical models based on the spectral datasets, including partial least squares-regression (PLS-R) and discriminant analysis (PLS-DA) as supervised registration and classification models. PLS-DA results of the N gradient in the roots and leaves showed an overall accuracy of 94% and 98%, respectively. PLS-R model performances of soluble carbohydrates and starch improved, in terms of the coefficient of determination (R2), if the leaf and root samples were integrated. Moreover, we found that the SWIR spectral region (1100–2500 nm) had unique reflectance features that revealed the carbohydrate composition and starch concentrations in the different plant tissues. The analyses also clustered the reflectance by tree part (root, branch, or leaf tissues) and N availability, forming a holistic model that can identify the nutritional status of trees. Conclusively, it is suggested that reflectance spectroscopy at the SWIR spectral region could guide precise fertilization by high-throughput identification of plants’ seasonal metabolism.

Effect of Lactobacillus plantarum expressing multifunctional glycoside hydrolases on the characteristics of alfalfa silage.

For the first time, Lactobacillus plantarum strains carrying heterologous genes encoding multifunctional glycoside hydrolases were constructed and used as additives for alfalfa silage. The chemical characteristics, nonstructural carbohydrate composition, and fermentation quality of alfalfa silage were examined. The supernatant of L. plantarum expressing CbXyn10C and Bgxg1 (LP11AG) showed activities on xylan, Avicel, and carboxymethylcellulose (CMC), while the supernatant of the wild-type L. plantarum showed no activity. When LP11AG was used as silage additive, the water-soluble carbohydrate content of alfalfa silage increased by 72%, 55%, and 155% compared with control when the silage was stored at 20 °C, 30 °C, and 40 °C, respectively. With LP11AG being used as an additive for the alfalfa silage stored at 20 °C, the hemicellulose, cellulose, and acid detergent ligninin (ADL) contents decreased by 17%, 6%, and 14% compared with the control (p < 0.05), respectively. Compared with the corresponding original contents, the contents of glucose, arabinose, galactose, and fructose detected in silage treated with LP11AG after 45 days of ensiling increased by 55%, 1494%, 68%, and 5% , respectively, when stored at 40 °C. Raffinose and stachyose, originally present in alfalfa, disappeared after ensiling. In conclusion, our results suggest that LP11AG provides a substantial benefit as a silage additive.

Impact of wilting and additives on fermentation quality and carbohydrate composition of mulberry silage.

ObjectiveThe objective of this study was to investigate the effects of wilting and additives on the fermentation quality, structural and non-structural carbohydrate composition of mulberry silages.MethodsThe selected lactic acid bacteria strains Lactobacillus plantarum ‘LC279063’ (L1), commercial inoculant Gaofuji (GF), and Trichoderma viride cellulase (CE) were used as additives for silage preparation. Silage treatments were designed as control (CK), L1, GF, or CE under three wilting rates, that is wilting for 0, 2, or 4 hours (h). After ensiling for 30 days, the silages were analyzed for the chemical and fermentation characteristics.ResultsThe results showed that wilting had superior effects on increasing the non-structural carbohydrate concentration and degrading the structural carbohydrate. After ensiling for 30 days, L1 generally had a higher fermentation quality than other treatments, indicated by the lower pH value, acetic acid, propionic acid and ammonia nitrogen (NH3-N) content, and the higher lactic acid, water soluble carbohydrate, glucose, galactose, sucrose, and cellobiose concentration (p<0.05) at any wilting rate. Wilting could increase the ratio of lactic acid/acetic acid and decrease the content of NH3-N.ConclusionThe results confirmed that wilting degraded the structural carbohydrate and increased the non-structural carbohydrate; and L1 exhibited better properties in improving fermentation quality and maintaining a high non-structural carbohydrates composition compared with the other treatments.

Effects of lactic acid bacteria and molasses on fermentation dynamics, structural and nonstructural carbohydrate composition and in vitro ruminal fermentation of rice straw silage.

ObjectiveThis study was to evaluate the fermentation dynamics, structural and nonstructural carbohydrate composition and in vitro gas production of rice straw ensiled with lactic acid bacteria and molasses.MethodsFresh rice straw was ensiled in 1-L laboratory silos with no additive control (C), Lactobacillus plantarum (L), molasses (M) and molasses+Lactobacillus plantarum (ML) for 6, 15, 30, and 60 days. After storage, the silages were subjected to microbial and chemical analyses as well as the further in vitro fermentation trial.ResultsAll additives increased lactic acid concentration, and reduced pH, dry matter (DM) loss and structural carbohydrate content relative to the control (p<0.05). The highest organic acid and residual sugar contents and lignocellulose reduction were observed in ML silage. L silage had the highest V-score with 88.10 followed by ML silage. L and ML silage improved in vitro DM digestibility as compared with other treatments, while in vitro neutral detergent fibre degradability (IVNDFD) was increased in M and ML silage (p<0.05). M silage significantly (p<0.05) increased propionic acid (PA) content and decreased butyric acid content and acetic acid/PA as well as 72-h cumulative gas production.ConclusionThe application of ML was effective for improving both the fermentation quality and in vitro digestibility of rice straw silage. Inclusion with molasses to rice straw could reduce in vitro ruminal gas production.

Ensiling characteristics, structural and nonstructural carbohydrate composition and enzymatic digestibility of Napier grass ensiled with additives

Ensiling characteristics, structural and nonstructural carbohydrate composition and enzymatic digestibility (ED) of Napier grass silage was examined. Napier grass ensiled with no additive control, 0.2% formic acid, 0.4% molasses, and 0.3% fibrolytic enzyme for, 7, 30, 60 and 90days. Additives increased lactic acid, soluble carbohydrate and decreased all of lignocellulosic contents except acid detergent lignin and pH than control. The highest value of nonstructural carbohydrate and large reduction in lignocellulosic contents was observed in formic acid and fibrolytic enzyme silage respectively. The content of glucose and fructose showed rapid drop in the first 7days of ensilage. Ensilage decreased lignocellulosic contents and increased ED compared to fresh material. The ED of formic acid and molasses silage was significantly higher than control and fibrolytic enzyme silages in all tested days. In summery the ensiling quality structural and nonstructural carbohydrate and ED value of mature Napier grass silage improved through additives.

Osmolality and Non-Structural Carbohydrate Composition in the Secondary Phloem of Trees across a Latitudinal Gradient in Europe.

Phloem osmolality and its components are involved in basic cell metabolism, cell growth, and in various physiological processes including the ability of living cells to withstand drought and frost. Osmolality and sugar composition responses to environmental stresses have been extensively studied for leaves, but less for the secondary phloem of plant stems and branches. Leaf osmotic concentration and the share of pinitol and raffinose among soluble sugars increase with increasing drought or cold stress, and osmotic concentration is adjusted with osmoregulation. We hypothesize that similar responses occur in the secondary phloem of branches. We collected living bark samples from branches of adult Pinus sylvestris, Picea abies, Betula pendula and Populus tremula trees across Europe, from boreal Northern Finland to Mediterranean Portugal. In all studied species, the observed variation in phloem osmolality was mainly driven by variation in phloem water content, while tissue solute content was rather constant across regions. Osmoregulation, in which osmolality is controlled by variable tissue solute content, was stronger for Betula and Populus in comparison to the evergreen conifers. Osmolality was lowest in mid-latitude region, and from there increased by 37% toward northern Europe and 38% toward southern Europe due to low phloem water content in these regions. The ratio of raffinose to all soluble sugars was negligible at mid-latitudes and increased toward north and south, reflecting its role in cold and drought tolerance. For pinitol, another sugar known for contributing to stress tolerance, no such latitudinal pattern was observed. The proportion of sucrose was remarkably low and that of hexoses (i.e., glucose and fructose) high at mid-latitudes. The ratio of starch to all non-structural carbohydrates increased toward the northern latitudes in agreement with the build-up of osmotically inactive C reservoir that can be converted into soluble sugars during winter acclimation in these cold regions. Present results for the secondary phloem of trees suggest that adjustment with tissue water content plays an important role in osmolality dynamics. Furthermore, trees acclimated to dry and cold climate showed high phloem osmolality and raffinose proportion.

Sensitivity of cold acclimation to elevated autumn temperature in field-grown Pinus strobus seedlings.

Climate change will increase autumn air temperature, while photoperiod decrease will remain unaffected. We assessed the effect of increased autumn air temperature on timing and development of cold acclimation and freezing resistance in Eastern white pine (EWP, Pinus strobus) under field conditions. For this purpose we simulated projected warmer temperatures for southern Ontario in a Temperature Free-Air-Controlled Enhancement (T-FACE) experiment and exposed EWP seedlings to ambient (Control) or elevated temperature (ET, +1.5°C/+3°C during day/night). Photosynthetic gas exchange, chlorophyll fluorescence, photoprotective pigments, leaf non-structural carbohydrates (NSC), and cold hardiness were assessed over two consecutive autumns. Nighttime temperature below 10°C and photoperiod below 12 h initiated downregulation of assimilation in both treatments. When temperature further decreased to 0°C and photoperiod became shorter than 10 h, downregulation of the light reactions and upregulation of photoprotective mechanisms occurred in both treatments. While ET seedlings did not delay the timing of the downregulation of assimilation, stomatal conductance in ET seedlings was decreased by 20–30% between August and early October. In both treatments leaf NSC composition changed considerably during autumn but differences between Control and ET seedlings were not significant. Similarly, development of freezing resistance was induced by exposure to low temperature during autumn, but the timing was not delayed in ET seedlings compared to Control seedlings. Our results indicate that EWP is most sensitive to temperature changes during October and November when downregulation of photosynthesis, enhancement of photoprotection, synthesis of cold-associated NSCs and development of freezing resistance occur. However, we also conclude that the timing of the development of freezing resistance in EWP seedlings is not affected by moderate temperature increases used in our field experiments.

Diversity of non-structural carbohydrates in the underground organs of five Iridaceae species from the Cerrado (Brazil)

South America has a great diversity in some tribes of the Iridaceae family. Most of the Iridaceae are geophytes, with underground organs bearing buds and reserve compounds, which favor their occurrence in seasonal environments, such as the Cerrado. Non-structural carbohydrates (NSC) are the main reserves in geophytes, essential to support phenological events, and protect plants against abiotic stresses. NSC may also reflect taxonomic relationships among plant groups. The objective of this study was to determine the contents and composition of NSC in underground organs of five Iridaceae species from the Cerrado (Cipura paludosa, Cipura xanthomelas, Trimezia cathartica, Trimezia juncifolia and Sisyrinchium vaginatum), representing the tribes Tigridieae, Trimezieae and Sisyrinchieae. Soluble carbohydrates and total fructose in oligo and polysaccharide fractions, and the starch contents were determined, and sugar composition was analyzed by HPAEC-PAD. The species from the tribes Trimezieae and Tigridieae showed similar NSC profiles, with considerable accumulation of starch and glucose, fructose, sucrose and maltose. Additionally, T. juncifolia also presented raffinose and 1-kestose. In contrast, S. vaginatum of the Sisyrinchieae has very low starch content and a distinct carbohydrate profile, predominating soluble carbohydrates, possibly of the raffinose family.

Measurement of the distribution of non-structural carbohydrate composition in onion populations by a high-throughput microplate enzymatic assay

Non-structural carbohydrate (NSC; glucose, fructose, sucrose and fructan) composition of onions (Allium cepa L.) varies widely and is a key determinant of market usage. To analyse the physiology and genetics of onion carbohydrate metabolism and to enable selective breeding, an inexpensive, reliable and practicable sugar assay is required to phenotype large numbers of samples. A rapid, reliable and cost-effective microplate-based assay was developed for NSC analysis in onions and used to characterise variation in tissue hexose, sucrose and fructan content in open-pollinated breeding populations and in mapping populations developed from a wide onion cross. Sucrose measured in microplates employing maltase as a hydrolytic enzyme was in agreement with HPLC-PAD results. The method revealed significant variation in bulb fructan content within open-pollinated 'Pukekohe Longkeeper' breeding populations over a threefold range. Very wide segregation from 80 to 600 g kg(-1) in fructan content was observed in bulbs of F2 genetic mapping populations from the wide onion cross 'Nasik Red × CUDH2150'. The microplate enzymatic assay is a reliable and practicable method for onion sugar analysis for genetics, breeding and food technology. Open-pollinated onion populations may harbour extensive within-population variability in carbohydrate content, which may be quantified and exploited using this method. The phenotypic data obtained from genetic mapping populations show that the method is well suited to detailed genetic and physiological analysis.

Influence of Leaf-fruit Ratio and Nitrogen Rate on Fruit Characteristics, Nitrogenous Compounds, and Nonstructural Carbohydrates in Young Persimmon Trees

The effects of fruit load and nitrogen (N) rate (0, 20, and 40 g N per tree) on fruit characteristics and the composition of nitrogenous compounds (e.g., amino acids and protein) and nonstructural carbohydrates in different plant tissues were determined in container-grown 5-year-old ‘Fuyu’ persimmon trees. Leaf-fruit (L/F) ratios were adjusted to either 20 (high) or 10 (low) by fruit thinning on 2 July. N was applied by fertigation as 1% (w/v) urea from 3 July to 20 Sept. The low L/F ratio decreased size and coloration of fruits, whereas increasing N rate resulted in fruits with low skin color and soluble solids but with high firmness. The high L/F ratio increased N concentrations only in 1- to 4-year-old wood and the trunk, whereas increasing N rate increased N concentrations of all tree tissues, especially of roots. The L/F ratio did not significantly affect the composition of nitrogenous compounds and carbohydrates in the tree tissues. As N rate increased, amino acid concentrations increased in all the tree parts, especially in aerial wood and roots where a three- to eightfold increase was observed between the 0- and 40-g N rates. Although not great, protein concentrations also increased with increasing N rate. Increasing N rate significantly reduced soluble sugars in fruit, trunk, and root and starch in leaf and root. The results indicated that an excessive supply of supplemental N could delay fruit maturation and reduce carbohydrate accumulations of ‘Fuyu’ trees regardless of the L/F ratios.

Freeze tolerance of Zoysia matrella (L.) Merrill as affected by late-season nitrogen application, and changes in carbohydrates during cold acclimation

This study was conducted with the aim of (1) assessing the development of freeze tolerance (LT50) in “Zeon” zoysiagrass under the effect of two different levels (15 and 30 g m−2) of late-season nitrogen applications, and (2) evaluating the dynamics of nonstructural carbohydrates composition during cold acclimation and overwintering. A combined approach with natural acclimation in the field, followed by monthly controlled exposure to sub-freezing temperatures, was employed to evaluate LT50. Fall color of “Zeon” zoysiagrass was improved by nitrogen applications, the latter extending the green period by more than one month. In October, the higher nitrogen treatment caused significantly less cold hardiness (LT50=−10.0°C) compared with the other treatments, but was beneficial to freeze tolerance in March. The controls reached cold hardiness in November, 1 month earlier than the N treatments, in agreement with the color retention data. Controls also showed a more linear freeze tolerance during the experimental period. Significant variations in total soluble sugars occurred in zoysiagrass tissues during the acclimation and de-acclimation process. In particular, in leaves and, partially, in stems, total soluble sugars (TSS) levels were associated with LT50, while sprigs and roots did not show any significant association between LT50 and TSS. Alteration of metabolism was more evident in the 30-g N treatment, in particular as regards the storage sink.

Physiological responses of Abies faxoniana seedlings to different non-growing-season temperatures as revealed by reciprocal transplantations at two contrasting altitudes

Detailed information on plants’ responses to varying temperature conditions will be useful when assessing the potential effects of climate change. We conducted reciprocal transplantations in Abies faxoniana Rehd. et Wils. to detect responses of seedlings to different winter (non-growing-season) temperatures in the Wanglang National Nature Reserve, China. Winter temperature variation might alter nitrogen allocation between 1-year-old leaves and branchlets. In leaves, coupling acclimation between photosynthesis potential (evident in pigment content and composition and carbon isotope composition (δ13C)) and adversity tolerance (detectable in peroxidase activity, malondialdehyde content, and nonstructural carbohydrate composition) to winter temperature variation was documented, whereas in branchlets, warming winter did not result in a δ13C-discriminative respiration process at tissue level. Although the experiment included only a short winter period, warming winter was found to pose a negative influence (decreased storage and increased leaf thickness) on A. faxoniana seedlings of subalpine forest understory. As both genetic adaptation and phenotypic plasticity could be responsible for such physiological variation, a detailed altitudinal investigation and a long-term experiment on A. faxoniana seedlings are needed to properly assess their responses to climate change.

Non-structural carbohydrates in the nutrition of high-yielding dairy cows during a transition period

The main aim of this study was to investigate experimentally the effect of different composition of non-structural carbohydrates (NFC) in prepartum feed rations administered to high-yielding dairy cows at a high concentration of NFC in the diet on dry matter intake both before and after parturition and on subsequent milk performance, body condition and physiological traits of rumen fluid and blood. Thirty-six high-yielding dairy cows were allocated into one of the three well-balanced groups (K, O, and C), and each group received a different feeding rations. Feeding rations differed in non-structural carbohydrate (NFC) structure. The "K" (control) group received a feeding ration with NFC in the form of maize starch in particular, while the feeding rations of the other two (experimental) groups contained either (besides maize starch) saccharose from dried sugar beet (the "O" group) or a dominant amount of NFC was in the form of saccharose (the "C" group). After calving, all dairy cows were given the same feeding ration from the first day after parturition. The experiment was conducted for 21 days before and 50 days after calving. FR in the form of total mixed ration was offered ad libitum. Dry matter intake, milk performance, body condition, live weight, and blood and rumen parameters were recorded for the duration of the experiment. Average daily dry matter intake before calving was highest in the "K" group (14.32 kg per head). Differences among groups were statistically significant (P &amp;lt; 0.05). Prepartum dry matter consumption dropped as the rate of saccharose in the diet of cows increased. Dry matter consumption levelled off after calving. Milk yield was also highest in the "K" group (43.71 kg/head/day), but fatness of milk and thus the production of fat corrected milk were lowest in this group. The highest milk fat content (4.10%) and fat corrected milk production (44.03 kg/head/day) were recorded in the "C" group, whereas the highest milk protein concentration was found in the milk of the "O" group. The composition of NFC affected dry matter intake before parturition, but these concentrations did not significantly affect dry matter intake, milk yield, milk composition, live weight, body condition or blood serum and rumen fluid parameters after calving