Responses Of Non-structural Carbohydrates Research Articles

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

Nonstructural carbohydrates (NSCs) 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 NSCs 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 interior, we collected samples of different age classes of H. ammodendron along a groundwater depth gradient of 3, 7, 10, and 14 meters. We measured the total concentrations of non-structural carbohydrates (NSCs) and their 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.

Response of Non-Structural Carbohydrates and Carbon, Nitrogen, and Phosphorus Stoichiometry in Pinus yunnanensis Seedlings to Drought Re-Watering

Response of Non-Structural Carbohydrates and Carbon, Nitrogen, and Phosphorus Stoichiometry in Pinus yunnanensis Seedlings to Drought Re-Watering

Responses of non-structural carbohydrates in <i>Betula platyphylla</i> leaves and fine roots to time since fire

Responses of non-structural carbohydrates in <i>Betula platyphylla</i> leaves and fine roots to time since fire

Responses of non-structural carbohydrates and biomass in plant to heavy metal treatment

The contamination of heavy metals profoundly impacts plant metabolic processes and various physiological indicators, such as non-structural carbohydrates (NSC). However, a comprehensive understanding of how NSC in plants respond to heavy metal treatment and how different experimental setting and plant types affect the response of plant NSC is still lacking. Here, we compiled data of 2084 observations of NSC from 85 published studies and conducted a meta-analysis to investigate the responses of soluble sugars, starch, the ratio of soluble sugar to starch, and total non-structural carbohydrates (TNSC) to heavy metal treatment. Our results showed that, under heavy metal treatment, foliar soluble sugars, foliar TNSC, and the ratio of soluble sugars to starch in both foliage and root increased significantly by 21.6 %, 11.6 %, 55.9 %, and 65.1 %, respectively; and foliar starch, root starch, and root TNSC decreased significantly by 10 %, 23.3 %, and 11 %, respectively; while root soluble sugars remained unchanged. The treatment of heavy metals significantly diminished the biomass of foliage, above-ground, and root by 12.3 %, 29.5 %, and 34.3 %, respectively. The responses of foliar NSC to heavy metal treatment were strongly dependent on leaf habit, the duration and concentration of heavy metal treatment, and soil pH value. The magnitude of the response of NSC to heavy metals increased with the duration and concentration of heavy metal treatment. Furthermore, the types of heavy metals modulated the magnitude of the response of foliar NSC to heavy metal treatment. Overall, our findings provide valuable insights into the responses of plant NSC to heavy metal stress and contribute to a comprehensive understanding of this crucial aspect of plant physiology.

Responses of non-structural carbohydrates and growth hormone in <i>Morus alba</i> seedlings to flooding stress

Responses of non-structural carbohydrates and growth hormone in <i>Morus alba</i> seedlings to flooding stress

Divergent allocations of nonstructural carbohydrates shape growth response to rainfall reduction in two subtropical plantations

Nonstructural carbohydrates (NSC) are indicators of tree carbon balance and play an important role in regulating plant growth and survival. However, our understanding of the mechanism underlying drought-induced response of NSC reserves remains limited. Here, we conducted a long-term throughfall exclusion (TFE) experiment to investigate the seasonal responses of NSC reserves to manipulative drought in two contrasting tree species (a broadleaved tree Castanopsis hystrix Miq. and a coniferous tree Pinus massoniana Lamb.) of the subtropical China. We found that in the dry season, the two tree species differed in their responses of NSC reserves to TFE at either the whole-tree level or by organs, with significantly depleted total NSC reserves in roots in both species. Under the TFE treatment, there were significant increases in the NSC pools of leaves and branches in C. hystrix, which were accompanied by significant decreases in fine root biomass and radial growth without significant changes in canopy photosynthesis; while P. massoniana exhibited significant increase in fine root biomass without significant changes in radial growth. Our results suggested that under prolonged water limitation, NSC usage for growth in C . hystrix is somewhat impaired, such that the TFE treatment resulted in NSC accumulation in aboveground organs (leaf and branch); whereas P . massoniana is capable of efficiently utilizing NSC reserves to maintain its growth under drought conditions. Our findings revealed divergent NSC allocations under experimental drought between the two contrasting tree species, which are important for better understanding the differential impacts of climate change on varying forest trees and plantation types in subtropical China.

13-year nitrogen addition increases nonstructural carbon pools in subtropical forest trees in southern China

Nonstructural carbohydrates (NSC) are important for plant growth and defense, and represent an important carbon pool that contributes to carbon (C) cycling and balance, but we know little about the variation of NSC in trees under global change scenarios, particularly nitrogen (N) deposition. Here, we investigated the responses of NSC (sugar and starch) pools of two dominant tree species (Castanopsis chinensis (broadleaf) and Pinus massoniana (coniferous)) to 13-year N treatments in different seasons in southern Chinese forests. Nitrogen addition increased NSC pools of the two tree species at the whole-tree and organ levels. We observed the larger starch pool (only in the wet season) and the highest increased NSC in the branches (3.8-fold) of C. chinensis following N addition. We also found the larger sugar pools (both in the dry and wet season) and the highest increased NSC in the roots (2.2-fold) of P. massoniana after N addition. Despite the increases in NSC of trees, we found no changes in chloroplast and photosynthetic capacity in response to N addition; however, the increased NSC may support prime defense of trees, as evidenced by significant correlations between NSC pools with volatile organic compounds (VOCs) emission (P < 0.05, R2 in the range of 0.5–0.8). Our findings indicate that long-term N deposition induced carbon distribution and adaptation strategies of different subtropical trees, with increased NSC storage at the whole-tree and organ levels and more NSC being allocated to the branches of broadleaf tree species and to the roots of coniferous tree species, respectively. This study provides a new insight into understanding the mechanisms of subtropical forest trees adapting and surviving under long-term N deposition, and is also important for exploring the ecosystem C-N coupling relationships under global environment changes.

The effects of persistent drought and waterlogging on the dynamics of nonstructural carbohydrates of Robinia pseudoacacia L. seedlings in Northwest China

BackgroundThe nonstructural carbohydrates (NSCs) of plants are posited to be crucial traits for the resistance and resilience of plants to climate change-induced drought and flooding. However, the potential effects of persistent drought and waterlogging on the dynamics of the NSCs and the underlying mechanisms are still poorly understood.MethodsWe measured the NSCs concentrations and pool size, photosynthetic rate and biomass of Robinia pseudoacacia L. seedlings for both 2015 and 2016 under five soil water treatments: 3%, 8%, 17%, 24% and 34% soil water content, representing extreme drought (ED), moderate drought (MD), the control group (CG), field capacity (FC) and waterlogging (WL) stresses, respectively. We observed the relationship between the pool size of NSCs and the survival of seedlings under water stress (drought and waterlogging) for 30 days in greenhouse.ResultsCompared with CG, the net photosynthetic rate decreased 91%, 67%, 34% and 71%, and the biomass decreased by 37%, 15%, 16% and 33% under ED, MD, FC and WL, respectively. The total NSC (TNSC) concentration was significantly increased by 154% under ED after 10 days and sharply decreased by 50% under ED after 30 days. The concentrations of soluble sugars (SS) were significantly increased by 100% under MD after 10 days and sharply decreased by 60% under ED after 30 days. Compared with GC, the response of NSCs, photosynthetic rate and biomass under ED were more dramatic than that under WL. The pool sizes of fructose and sucrose were larger under ED and WL, but the maximum pool size of starch occurred under the CG. The depletion of NSCs was not observed under ED at the end of the experiments in both 2015 and 2016.ConclusionsOur results indicate that the dynamics of NSCs is an important physiological feature of plant adaptation and resistance to drought and waterlogging. In addition, high sugars concentrations are beneficial for the plants during the short-term extreme drought and the longer term mild drought or waterlogging.

Effects of defoliation on the allocation of non-structural carbohydrates in roots of Fraxinus mandshurica seedlings.

Global climate changes would lead to outbreaks of leaf-feeding insects. Leaf loss could reduce photosynthate production, with consequences on non-structural carbohydrates (NSC) storage and allocation in trees. In this study, the responses of NSC and its compartment concentrations in tap-, coarse- and the first to fifth order fine roots of 2-year-old seedlings of Fraxinus mandshurica to defoliation (40% loss of leaf area) were measured from June to October. The results showed that NSC and its compartment concentrations in roots exhibited distinct seasonal dynamics in both control and defoliation treatments. Following defoliation, NSC concentration decreased in tap- and coarse roots by 3.8% and 30.7%, respectively, while increased in the first five order roots by 1.2%-23.5%, to which starch contributed majorly for each root compartment. Soluble sugar concentration was enhanced by defoliation in tap- and coarse roots by 7.1% and 62.3%, respectively, but decreased in the first to fifth order roots by 2.7%-42.8%. Defoliation had different influences on starch and soluble sugar, with positive effects on the ratio of soluble sugar to starch concentrations in tap- and coarse roots but negative effects on the first to fifth order roots. Overall, defoliation decreased photosynthate production in leaves, leading to the remobilization of starch in tap- and coarse roots and the transportation as soluble sugar to fine roots, as well as the following storage in these roots, which would facilitate the resistance of fine roots to the low temperature in winter.

The sweet side of global change-dynamic responses of non-structural carbohydrates to drought, elevated CO2 and nitrogen fertilization in tree species.

Non-structural carbohydrates (NSC) play a central role in plant functioning as energy carriers and building blocks for primary and secondary metabolism. Many studies have investigated how environmental and anthropogenic changes, like increasingly frequent and severe drought episodes, elevated CO2 and atmospheric nitrogen (N) deposition, influence NSC concentrations in individual trees. However, this wealth of data has not been analyzed yet to identify general trends using a common statistical framework. A thorough understanding of tree responses to global change is required for making realistic predictions of vegetation dynamics. Here we compiled data from 57 experimental studies on 71 tree species and conducted a meta-analysis to evaluate general responses of stored soluble sugars, starch and total NSC (soluble sugars + starch) concentrations in different tree organs (foliage, above-ground wood and roots) to drought, elevated CO2 and N deposition. We found that drought significantly decreased total NSC in roots (-17.3%), but not in foliage and above-ground woody tissues (bole, branch, stem and/or twig). Elevated CO2 significantly increased total NSC in foliage (+26.2%) and roots (+12.8%), but not in above-ground wood. By contrast, total NSC significantly decreased in roots (-17.9%), increased in above-ground wood (+6.1%), but was unaffected in foliage from N fertilization. In addition, the response of NSC to three global change drivers was strongly affected by tree taxonomic type, leaf habit, tree age and treatment intensity. Our results pave the way for a better understanding of general tree function responses to drought, elevated CO2 and N fertilization. The existing data also reveal that more long-term studies on mature trees that allow testing interactions between these factors are urgently needed to provide a basis for forecasting tree responses to environmental change at the global scale.

Staged Responses of Non-structural Carbohydrates of Pinus tabulaeformis Seedlings to Drought Stress

Staged Responses of Non-structural Carbohydrates of Pinus tabulaeformis Seedlings to Drought Stress

Differential Responses in Non-structural Carbohydrates of Machilus ichangensis Rehd. et Wils. and Taxus wallichiana Zucc. Var. chinensis (Pilg.) Florin Seedlings to Elevated Ozone

Tropospheric ozone (O3) enrichment could change the carbon (C) metabolism and decrease the C stock for tree species. To assess the differences in response of non-structural carbohydrates (NSCs) between Machilus ichangensis Rehd. et Wils. (M. ichangensis) and Taxus wallichiana Zucc. var. chinensis (Pilg.) Florin (T. wallichiana) with elevated O3, one-year-old container seedlings of the two species were grown with ambient air (AA), 100 ppb (elevated O3 treatment 1, E1-O3), and 150 ppb (elevated O3 treatment 2, E2-O3) treatments using open top chambers. During the experiment, net photosynthetic rate (Pn) of M. ichangensis and T. wallichiana were examined once each month from April to October. At the end of experiment, plants were harvested to examine the NSC concentrations and tissue C stocks. Results suggest elevated O3 significantly decreased Pn and total C stock for both M. ichangensis and T. wallichiana, while it also significantly decreased the NSC concentrations in the foliage of the two species, and the roots of T. wallichiana. However, the concentrations of NSCs and their components in other tissues did not change obviously. Significant increases in the ratio of soluble sugars to starch were observed in the foliage of M. ichangensis and the roots of T. wallichiana. For M. ichangensis, Pn was significantly and positively correlated with NSCs and their components only in foliage. In contrast, NSCs in both foliage and roots were significantly and positively correlated with Pn for T. wallichiana. Based on the results for Pn, total C stock, and NSC concentrations, M. ichangensis appeared more sensitive to elevated O3 than T. wallichiana. It is suggested that the strategies of C allocation in the two species are different with elevated O3.

Responses of Non-structural Carbohydrates and C:N:P Stoichiometry of Bothriochloa ischaemum to Nitrogen Addition on the Loess Plateau, China

Bothriochloa ischaemum: (L.) Keng is an excellent native pasture and forage species on the Loess Plateau, China, which is low in soil nitrogen. Little is known about the effects of N addition on biomass, concentrations of non-structural carbohydrates (NSCs), and the carbon:nitrogen:phosphorus (C:N:P) stoichiometry of B. ischaemum in this area. We examined these responses in both plant tissues and soil to N additions of 0 (N0), 2.5 (N1), 5.0 (N2), and 10.0 (N3) g N m−2 year−1. Biomass was maximal with N additions between 2.5 and 5.0 g N m−2 year−1. The increase in biomass was more rapid above- than belowground. N addition had no significant effect on the C:N:P ratios in the plant tissues, except for the aboveground biomass N:P ratio which increased significantly. The response to N addition of aboveground biomass and the N:P ratio suggests that N is not likely the limiting nutrient for the growth of B. ischaemum when biomass N:P ratios are between 25.5 and 27.1. In contrast to the plant tissues, the soil C:N and C:P ratios, but not the N:P ratio, decreased significantly with increasing N addition, indicating that N addition may help improve soil quality in this area. Both above- and belowground NSC concentrations varied significantly with N addition, with maxima of 102.4 g kg−1 in N1 and 49.6 g kg−1 in N2. The application of N could be a management option for improving ecosystem biomass production and NSC concentrations in the grasses on the Loess Plateau.

Different responses of non-structural carbohydrates in above-ground tissues/organs and root to extreme drought and re-watering in Chinese fir (Cunninghamia lanceolata) saplings

The total NSC concentration in the roots declined more significantly than in the above-ground tissues/organs under drought treatment, and the level did not return to that of the control after re-watering. Non-structural carbohydrates (NSC) reflect the relative balance between C-gain (photosynthesis) and C-loss (respiration) and play a pivotal role in carbon cycling in a forest ecosystem. However, little is known regarding the effects of extreme drought and re-watering on the NSC status in different tissues/organs. This study examined the variation in NSC concentrations in different tissues/organs and the total NSC pool sizes in Chinese fir (Cunninghamia lanceolata) saplings after drought and re-watering. Results showed that significant differences were observed in the concentrations of total NSC and its components in the different tissues/organs. For example, the NSC concentrations were nine times higher in bark than in stemwood. Moreover, the responses of NSC and its components to extreme drought also varied in different tissues/organs. Drought either significantly increased or maintained the total NSC concentration in the above-ground tissues/organs. By contrast, drought reduced the total NSC concentration in the sapling roots. Furthermore, the results also showed that extreme drought leads to sapling death, which is supported by the result of needle staining and the failure of the total NSC concentration to recover after re-watering. The concentrations of NSC and its components further decreased, and a more pronounced decline was observed in the roots than in the above-ground tissues/organs after re-watering. We speculated that drought can cause failure in carbon translocation between the above- and below-ground tissues/organs and thus cause varied responses of different tissues/organs to extreme drought and re-watering. Overall, these findings suggest the need to investigate the potential differential responses of various tissues/organs to climate change.

Geographic pattern and effects of climate and taxonomy on nonstructural carbohydrates of Artemisia species and their close relatives across northern China

Nonstructural carbohydrates (NSCs) are the primary products of photosynthesis and have implications for determining the carbon (C) limitation under current environmental conditions and the impact of climate change on the C balance in ecosystems. Yet, heretofore little was known about how climate and taxonomy affect NSC at the regional or global scale. We explored geographic patterns and effects of climate and taxonomy on the NSC in the aboveground organs of Artemisia species and their close relatives from 65 sites across northern China. Hierarchical linear models (HLMs) showed that sugar concentration decreased with increasing altitude and that the response of NSC to the altitudinal gradient differed among species. NSC concentration was affected by climate of the warmest quarter rather than annual climate. Sugar and starch concentrations differed significantly among species. Within the NSC C pool, species identity explained more of the total variance of sugar C than that of starch C. Our results show that the NSC pattern at a large geographical scale differs from that at the local scale. As a temporary storage of C, NSCs appear to be a direct product of the photosynthetic process rather than to function as protectants against environmental stresses during the growing season at the regional scale. Therefore, different species, even among closely related taxa, may vary in their adaptation to environmental gradients via the physiological adjustment of NSCs at the regional scale.

Dynamics of non-structural carbohydrates in three Mediterranean woody species following long-term experimental drought

Stored non-structural carbohydrates (NSC) have been proposed as a key determinant of drought resistance in plants. However, the evidence for this role is controversial, as it comes mostly from observational, short-term studies. Here, we take advantage of a long-term experimental throughfall reduction to elucidate the response of NSC to increased drought 14 years after the beginning of the treatment in three Mediterranean resprouter trees (Quercus ilex L., Arbutus unedo L. and Phillyrea latifolia L.). In addition, we selected 20 Q. ilex individuals outside the experimental plots to directly assess the relationship between defoliation and NSC at the individual level. We measured the seasonal course of NSC concentrations in leaves, branches and lignotuber in late winter, late spring, summer, and autumn 2012. Total concentrations of NSC were highest in the lignotuber for all species. In the long-term drought experiment we found significant depletion in concentrations of total NSC in treatment plots only in the lignotuber of A. unedo. At the same time, A. unedo was the only species showing a significant reduction in BAI under the drought treatment during the 14 years of the experiment. By contrast, Q. ilex just reduced stem growth only during the first 4 years of treatment and P. latifolia remained unaffected over the whole study period. However, we found a clear association between the concentrations of NSC and defoliation in Q. ilex individuals sampled outside the experimental plots, with lower total concentrations of NSC and lower proportion of starch in defoliated individuals. Taken together, our results suggest that stabilizing processes, probably at the stand level, may have been operating in the long-term to mitigate any impact of drought on NSC levels, and highlight the necessity to incorporate long-term experimental studies of plant responses to drought.