Carbohydrate Content Of Plants Research Articles

Relationship between Photosynthetic Capacity and Carbohydrate Content of Mangifera indica cv. Harumanis in Response to Girdling and Paclobutrazol

Girdling and paclobutrazol have been related with the effects on the photosynthetic capacity and carbohydrate content of plants. The physiological changes caused by these methods distress the growth and development of plants in general. A field experiment was carried out from August 2021 to June 2022 on 5 years of open-field Mangifera indica cv. Harumanis trees grown at Malaysian Agriculture Research and Development Institute (MARDI), Serdang, Selangor. The objective of this experiment was to understand the relationship between girdling, paclobutrazol application, combined methods and untreated trees on plant photosynthetic performances and carbohydrate content in the leaves. The treatments were performed on 1st December 2021, and the measurements of leaf gas exchanges and carbohydrate content were performed 4th weeks later on fully expanded leaves shoot, experiencing similar light exposure. In the study, the combination of girdling and paclobutrazol application resulted in a significant decrease in photosynthetic rate (Pn), stomatal conductance (gs) and transpiration rate (Tr) but significantly increase in intercellular CO2 concentration (Ci) and carbohydrate content.

Food preferences in a generalist pollen feeder: A nutritional strategy mainly driven by plant carbohydrates

IntroductionAnimal nutritional strategies have been extensively studied in vertebrates, where generalism at the individual scale is the rule. In insect herbivores, the determinants of the nutritional strategy of individual-scale generalists remain poorly studied, and the focus has been placed mainly on the influence of plant defense. Moreover, the integration of a physiological dimension in such studies remains rare. Here, we investigated the determinants of the nutritional strategy of pre-diapausing pollen beetles,Brassicogethes aeneus, with a focus on the influence of macronutrients. Before their diapause, pollen beetles are known to feed from plants belonging to many different families. This raises three questions: (i) Is the generalism of pollen beetles a populational consequence of individuals specialized on different plant families? (ii) Do individuals feed at random on flowers available or do they have a particular nutritional strategy? and (iii) In case of non-random feeding choices, do pollen macronutrients explain this nutritional strategy?MethodsTo answer these questions, we used a series of laboratory experiments including feeding choice tests on flowers and artificial substrates, quantification of pollen nutrient content, quantification of the insect energetic budget, and performance experiments.ResultsWe show that pollen beetles are generalist at the individual scale, and that clear and stable food preferences are established over a few hours in a multi-choice context. Pollen beetles prefer to feed on flowers with a carbohydrate-rich pollen, and this preference is adaptive since performance correlates positively with the plant carbohydrate content. This better performance may be explained by the fact that individuals feeding on carbohydrate-rich resources accumulate more glycogen and total energetic reserves.DiscussionThis study represents one of the few evidences of generalism at the individual scale in an herbivorous insect. It provides a better understanding of the nutritional strategy of a non-bee pollen feeder and shows the importance of carbohydrates in this strategy. It highlights the need to combine assessments of the plant macronutrient content and insect energetic budget in an adaptive framework to better understand the nutritional strategies of herbivores.

Transient Effects of Snow Cover Duration on Primary Growth and Leaf Traits in a Tundra Shrub.

With the recent climate warming, tundra ecotones are facing a progressive acceleration of spring snowpack melting and extension of the growing season, with evident consequences to vegetation. Along with summer temperature, winter precipitation has been recently recognised as a crucial factor for tundra shrub growth and physiology. However, gaps of knowledge still exist on long-living plant responses to different snowpack duration, especially on how intra-specific and year-to-year variability together with multiple functional trait adjustments could influence the long-term responses. To fill this gap, we conducted a 3 years snow manipulation experiment above the Alpine treeline on the typical tundra species Juniperus communis, the conifer with the widest distributional range in the north emisphere. We tested shoot elongation, leaf area, stomatal density, leaf dry weight and leaf non-structural carbohydrate content of plants subjected to anticipated, natural and postponed snowpack duration. Anticipated snowpack melting enhanced new shoot elongation and increased stomatal density. However, plants under prolonged snow cover seemed to compensate for the shorter growing period, likely increasing carbon allocation to growth. In fact, these latter showed larger needles and low starch content at the beginning of the growing season. Variability between treatments slightly decreased over time, suggesting a progressive acclimation of juniper to new conditions. In the context of future warming scenarios, our results support the hypothesis of shrub biomass increase within the tundra biome. Yet, the picture is still far from being complete and further research should focus on transient and fading effects of changing conditions in the long term.

Plant carbohydrate content limits performance and lipid accumulation of an outbreaking herbivore: Nutrition limits performance of locusts

Plant carbohydrate content limits performance and lipid accumulation of an outbreaking herbivore: Nutrition limits performance of locusts

Plant carbohydrate content limits performance and lipid accumulation of an outbreaking herbivore.

Locusts are major intermittent threats to food security and the ecological factors determining where and when these occur remain poorly understood. For many herbivores, obtaining adequate protein from plants is a key challenge. We tested how the dietary protein : non-structural carbohydrate ratio (p : c) affects the developmental and physiological performance of 4th-5th instar nymphs of the South American locust, Schistocerca cancellata, which has recently resurged in Argentina, Bolivia and Paraguay. Field marching locusts preferred to feed on high carbohydrate foods. Field-collected juveniles transferred to the laboratory selected artificial diets or local plants with low p : c. On single artificial diets, survival rate increased as foods became more carbohydrate-biased. On single local plants, growth only occurred on the plant with the lowest p : c. Most local plants had p : c ratios substantially higher than optimal, demonstrating that field marching locusts must search for adequate carbohydrate or their survival and growth will be carbohydrate-limited. Total body lipids increased as dietary p : c decreased on both artificial and plant diets, and the low lipid contents of field-collected nymphs suggest that obtaining adequate carbohydrate may pose a strong limitation on migration for S. cancellata. Anthropogenic influences such as conversions of forests to pastures, may increase carbohydrate availability and promote outbreaks and migration of some locusts.

Impact of different Fertilizer Combinations on the Biochemical Parameters of Wheat (Triticum aestivum L.)

In order to estimate the comparative impact of organic manure (Vermicompost, Farmyard manure), chemical fertilizers (NPK, Urea) and their combinations on protein and carbohydrate content of Wheat during different growth stages, an experiment was conducted by using Randomized Block Design (RBD) with three replications. The results revealed that at 15 days after sowing protein content of wheat (leaves) recorded maximum (15.73 mg/gm) in 10% Vermicompost +100 gm NPK fertilizer treatment and minimum (7.92 mg/gm) in control. However at 60 days after sowing it was reported maximum (17.92 mg/gm) in 10% Vermicompost +100 gm NPK fertilizer combination and minimum (9.68 mg/gm) in control. In the wheat grains, protein content was maximum (127.42 mg/gm) in 10% Vermicompost +100 gm NPK followed by 10% VC+100 gm urea (123.59 mg/gm) and minimum (87.53 mg/gm) in control. Moreover, the carbohydrate content of plant leaves at 15 days after sowing was recorded maximum (37.52 mg/gm) in 10% Vermicompost +100 gm NPK treatment and minimum (19.35 mg/gm) in control. However at 60 days after sowing it was observed maximum (39.74 mg/gm) in 10% VC+100 gm NPK and minimum (21.41 mg/gm) in control. Furthermore in grains, the carbohydrate content was observed maximum (496.72 mg/gm) in 10% FYM+100 gm NPK followed by 10% VC+100 gm urea (488.61 mg/gm).

Transgenic switchgrass (Panicum virgatum L.) targeted for reduced recalcitrance to bioconversion: a 2-year comparative analysis of field-grown lines modified for target gene or genetic element expression.

SummaryTransgenic Panicum virgatum L. silencing (KD) or overexpressing (OE) specific genes or a small RNA (GAUT4‐KD, miRNA156‐OE, MYB4‐OE,COMT‐KD and FPGS‐KD) was grown in the field and aerial tissue analysed for biofuel production traits. Clones representing independent transgenic lines were established and senesced tissue was sampled after year 1 and 2 growth cycles. Biomass was analysed for wall sugars, recalcitrance to enzymatic digestibility and biofuel production using separate hydrolysis and fermentation. No correlation was found between plant carbohydrate content and biofuel production pointing to overriding structural and compositional elements that influence recalcitrance. Biomass yields were greater for all lines in the second year as plants establish in the field and standard amounts of biomass analysed from each line had more glucan, xylan and less ethanol (g/g basis) in the second‐ versus the first‐year samples, pointing to a broad increase in tissue recalcitrance after regrowth from the perennial root. However, biomass from second‐year growth of transgenics targeted for wall modification, GAUT4‐KD,MYB4‐OE,COMT‐KD and FPGS‐KD, had increased carbohydrate and ethanol yields (up to 12% and 21%, respectively) compared with control samples. The parental plant lines were found to have a significant impact on recalcitrance which can be exploited in future strategies. This summarizes progress towards generating next‐generation bio‐feedstocks with improved properties for microbial and enzymatic deconstruction, while providing a comprehensive quantitative analysis for the bioconversion of multiple plant lines in five transgenic strategies.

Increasing the carbohydrate storage capacity of plants by engineering a glycogen-like polymer pool in the cytosol

Global demand for higher crop yields and for more efficient utilization of agricultural products will grow over the next decades. Here, we present a new concept for boosting the carbohydrate content of plants, by channeling photosynthetically fixed carbon into a newly engineered glucose polymer pool. We transiently expressed the starch/glycogen synthases from either Saccharomyces cerevisiae or Cyanidioschyzon merolae, together with the starch branching enzyme from C. merolae, in the cytosol of Nicotiana benthamiana leaves. This effectively built a UDP-glucose-dependent glycogen biosynthesis pathway. Glycogen synthesis was observed with Transmission Electron Microscopy, and the polymer structure was further analyzed. Within three days of enzyme expression, glycogen content of the leaf was 5–10 times higher than the starch levels of the control. Further, the leaves produced less starch and sucrose, which are normally the carbohydrate end-products of photosynthesis. We conclude that after enzyme expression, the newly fixed carbohydrates were routed into the new glycogen sink and trapped. Our approach allows carbohydrates to be efficiently stored in a new subcellular compartment, thus increasing the value of vegetative crop tissues for biofuel production or animal feed. The method also opens new potential for increasing the sink strength of heterotrophic tissues.

Overexpression of plastidial thioredoxin f leads to enhanced starch accumulation in tobacco leaves

Starch, the most abundant storage carbohydrate in plants, has been a major feedstock for first-generation biofuels. Growing fuel demands require, however, that the starch yields of energy crops be improved. Leaf starch is synthesised during the day and degraded at night to power nonphotosynthetic metabolism. Redox regulation has been associated with the coordination of the enzymes involved in starch metabolism, but neither the signals nor mechanisms that regulate this metabolism are entirely clear. In this work, the thioredoxin (Trx) f and m genes, which code for key enzymes in plastid redox regulation, were overexpressed from the plastid genome. Tobacco plants overexpressing Trx f, but not Trx m, showed an increase of up to 700% in leaf starch accumulation, accompanied by an increase in leaf sugars, specific leaf weight (SLW), and leaf biomass yield. To test the potential of these plants as a nonfood energy crop, tobacco leaves overexpressing Trx f were subjected to enzymatic hydrolysis, and around a 500% increase in the release of fermentable sugars was recorded. The results show that Trx f is a more effective regulator of photosynthetic carbon metabolism in planta than Trx m. The overexpression of Trx f might therefore provide a means of increasing the carbohydrate content of plants destined for use in biofuel production. It might also provide a means of improving the nutritional properties of staple food crops.

HXK1 regulates carbon catabolism, sporulation, fumonisin B1 production and pathogenesis in Fusarium verticillioides

In Fusarium verticillioides, a ubiquitous pathogen of maize, virulence and mycotoxigenesis are regulated in response to the types and amounts of carbohydrates present in maize kernels. In this study, we investigated the role of a putative hexokinase-encoding gene (HXK1) in growth, development and pathogenesis. A deletion mutant (Δhxk1) of HXK1 was not able to grow when supplied with fructose as the sole carbon source, and growth was impaired when glucose, sucrose or maltotriose was provided. Additionally, the Δhxk1 mutant produced unusual swollen hyphae when provided with fructose, but not glucose, as the sole carbon source. Moreover, the Δhxk1 mutant was impaired in fructose uptake, although glucose uptake was unaffected. On maize kernels, the Δhxk1 mutant was substantially less virulent than the wild-type, but virulence on maize stalks was not impaired, possibly indicating a metabolic response to tissue-specific differences in plant carbohydrate content. Finally, disruption of HXK1 had a pronounced effect on fungal metabolites produced during colonization of maize kernels; the Δhxk1 mutant produced approximately 50 % less trehalose and 80 % less fumonisin B₁ (FB₁) than the wild-type. The reduction in trehalose biosynthesis likely explains observations of increased sensitivity to osmotic stress in the Δhxk1 mutant. In summary, this study links early events in carbohydrate sensing and glycolysis to virulence and secondary metabolism in F. verticillioides, and thus provides a new foothold from which the genetic regulatory networks that underlie pathogenesis and mycotoxigenesis can be unravelled and defined.

Chlorophyll fluorescence parameters, CO 2 photosynthetic rate and regeneration capacity as a result of complete submergence and subsequent re-emergence in rice ( Oryza sativa L.)

Regeneration capacity of submerged rice ( Oryza sativa) seedlings in terms of CO 2 photosynthetic rate, chlorophyll a fluorescence and chlorophyll and carbohydrate content were investigated in three Indica rice cultivars namely FR 13A, Kalaputia and IR 42 that differed in submergence tolerance. Twenty-one day old plants were completely submerged under water for 8 days. Subsequently, plants were kept under normal conditions with 5–10 cm of stagnant water above soil surface for a further period of 15 days. After complete submergence, all genotypes showed inhibition of CO 2 photosynthetic rate. Submergence treatment resulted in a significant reduction of Rubisco activity. Maximal photochemical efficiency ( F v/ F m) of PS II and area above the fluorescence curve between F o and F m decreased more under submergence especially in susceptible cultivar IR 42. When re-aerated, the plants recovered to various degrees. The carbohydrate content of plants was found to be significantly and positively associated with submergence tolerance and regeneration growth. The tolerant cultivar (FR 13A) could survive submergence apparently because it possessed 1.9–2.0 and 3.2–3.7-fold more non-structural carbohydrate content before and after submergence compared to the susceptible cultivar (IR 42) and it had a better capability to restore its photosynthetic capacity during post-submergence periods.

Effect of defoliation height and redefoliation interval on regrowth and survival of perennial ryegrass (Lolium perenne) in subtropical dairy pastures

A cut plot study was undertaken on the subtropical north coast of New South Wales, Australia, to determine the effect of defoliation height and redefoliation interval on dry matter yield and persistence of perennial ryegrass (Lolium perenne L.) pastures. The pasture was established on 7 April 1998 and plots were irrigated to replace evapotranspiration loss. The study was a completely randomised block design with plots of 2 by 1 m and treatments replicated 3 times. In winter (commencing 13 July) plots were defoliated to 20, 50 or 120 mm stubble height and either not redefoliated or redefoliated at 3, 6 or 3 and 6 days after initial defoliation. In spring (commencing 28 October) plots were redefoliated as for winter but only to 50 mm stubble height. After imposition of the redefoliation treatments, the plots were allowed to regrow until the non-redefoliated treatments had regrown 3 new leaves per tiller (subsequently referred to as a regrowth cycle) and then again defoliated (regrowth cycle 1). Plots cut in winter were then halved with one half (A plots) continuing to be subject to the redefoliation treatment for 4 more regrowth cycles until regrowth cycle 1 in spring was completed on 24 November, while the other half (B plots) were a carryover comparison of redefoliation treatment in regrowth cycle 1. Both A and B plots continued to be subjected to the same defoliation height treatments as imposed in regrowth cycle 1. From 24 November to 30 March 1999, plots were defoliated at 50 mm height each time 3 new leaves per tiller had regrown.Plots defoliated to 20 or 50 mm height during regrowth cycle 1 in winter yielded 21% more dry matter than plots cut to 120 mm height while redefoliation at 6 or 3 and at 6 days produced 14% less dry matter than plots not redefoliated or redefoliated at 3 days. Continued redefoliation at 6 days (comparison within A plots) reduced dry matter yield by 63% compared with no redefoliation or redefoliation at 3 days, but only in plots defoliated to 20 or 50 mm height.Plant density in the autumn (March 1999) of the year after establishment was positively related to defoliation height over regrowth cycles 1–5 of the previous year (35, 55 or 77 plants/m2 for plots defoliated at 20, 50 or 120�mm, respectively). Plant density of plots not redefoliated or redefoliated at 3 days over regrowth cycles 1–5 was 63% higher (70 plants/m2) than for the other treatment combination (43 plants/m2) at P = 0.07 level of significance.Plants cut to 20 or 50 mm stubble height at the commencement of regrowth cycle 1 in winter had a stubble water-soluble carbohydrate content of 5.2%, decreasing to 2.3% at day 6 post-defoliation. The water-soluble carbohydrate content of plants cut to 120 mm were initially higher at 8% and fell to only 6.4% by day 6.The redefoliation treatments imposed in this study were designed to simulate the regrazing of regrowth shoots in an extended grazing bout at various defoliation heights. The results confirm the negative effects of redefoliation, at 6 days in the winter to spring period, on both dry matter yield and plant survival over the subsequent summer in the subtropics. In contrast to winter, redefoliation in late spring had no effect on dry matter yield or plant density. The results also indicate a compromise between the benefits of more lax grazing for persistence and harder grazing for pasture utilisation.

Relationship Between Assimilate Supply and Essential Oil Accumulation in Annual and Biennial Caraway (Carum carvi L.)

ABSTRACT The reported lower essential oil content of seeds of annual caraway compared with seeds of biennial caraway has three possible causes: genetic differences, differences in the location where the two types are grown, and differences in weather conditions during seed filling, since both forms of caraway ripen in a different period of the year. To study these possible causes, we compared essential oil formation in annual and biennial caraway in a greenhouse experiment, thereby excluding differences in location and weather conditions during seed filling. Surprisingly, under these conditions fruits of annual caraway had a higher dry-weight and contained more essential oil than fruits of biennial caraway. Measurement of plant carbohydrate content suggested that this was because more assimilate was available per fruit in annual caraway. It is concluded that there is no genetic barrier preventing annual caraway from reaching an essential oil content similar to biennial caraway. The low essential oil conte...

The influence of defoliation and nitrogen on the regrowth of Rhodes grass (Chloris gayana Kunth). 2. Etiolated growth and non-structural carbohydrate, total-N and nitrate-N content.

Data are given on the chemical composition of Rhodes grass cv. Common grown in a heated glasshouse [see HbA 42, 1910]. Plants given high N (8.29 meq/100 g soil) contained about 30% less carbohydrate in the stubble and roots than those given low N (1.43 meq/100g). The carbohydrate content of plants cut every 28 days was generally lower than that of plants cut every 14 days. Amounts of etiolated growth in darkness after cutting were positively correlated with the carbohydrate level in the roots and in the stubble. The percentage of tillers exhibiting regrowth in darkness increased linearly up to about 60% with increase in the amount of etiolated growth. Contents of total N in roots and in stubble were almost double at the high rate of N. Amounts of nitrate as a proportion of total N were about 12% in low-N plants and up to 47% in high-N plants. The nitrate contents of shoots, stubble and roots were negatively correlated with the carbohydrate levels in each of these tissues. The overall difference in carbohydrate level between shoots, stubble and roots was relatively small. It was concluded that Rhodes grass had a limited capacity to accumulate reserve material when grown under conditions favouring rapid growth. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Environmental Effects on the Resistance of Rice Seedlings to Complete Submergence

The survival of rice seedlings (Oryza sativa L.) after complete Submergence in water decreased with increased duration of submergence; with increased depth, temperature, and turbidity of water; and with increased rates of N fertilization. Survival increased with high light intensity and plant carbohydrate content. Factors that influence the survival of submerged plants also determine the amounts of N and carbohydrate in the plant.

Studies on the salt tolerance of vegetable crops in sand culture. I

From 1957 to 1960, vegetable crops were grown in sand culture under glass at various concentrations of NaCl to study their relative salt tolerance, visual symptoms of salt injury, and effect of NaCl on absorption of nutrient elements and carbohydrate content of plants. HOAGLAND's solution was used as the basic solution (control), and 1000, 2000, 4000 8000, or 16000 ppm of NaCl was added to it. The present paper, as a part of the studies, deales with the results of experiments on six fruit vegetables, namely, tomato, pepper, cucumber (the 1000 ppm treatment was omitted), broad bean, snap bean (the 100 and 16000 ppm were omitted), and strawberry. 1. With increasing concentration of NaCl, plants were dwarfed and the emergence of lateral shoots was restricted. Concentrations of NaCl above 8000 ppm in cucumbers, broad beans, and snap beans, and above 4000 ppm in strawberries caused severe dying off of older leaves and finaly death of entire plant. With the increase of NaCl, the fresh weight of tops (vines) was reduced, excpet that tomatoes showed the greatest weight at the 1000 ppm treatment The yield of fruits, however, was reduced in any crop with the increase of NaCl. The concentrations of NaCl in the solution corresponding to a 50 percent reduction in yield of fruits of tomatoes, peppers, cucumbers, broad beans, and strawberries were about 3500, 3000, 3000, 2500, 2000, and 1000 ppm, respec-tively. In tomatoes, and peppers, the reduction in yield of fruits was more significant than that of vines. The dry weight percentage of tops generally decreased in high salt treatments. 2. The number of flowers tended in general to parallel declining vegetative growth as salinity in-creased. The rate of fruit setting was reduced mark-edly in the treatments above 8000 ppm in tomatoes and above 4000 ppm in peppers. In most crops, the dates of first flower opening and of first harvesting were not so remarkably affected by NaCl treatments, but in peppers, severe shedding of early fruits in higher salt treaments retarded the first harvest. No apparently harmful effects of NaCl treatments were observed on the fertility or germination percentage of pollens, and on the seed set. 3. Symptoms of salt injury were as follows: In tomatoes, leaves were dark green from 1000 to 8000 ppm, but were chlorotic at the 16000 ppm. In pep-pers, leaves were chlorotic and leaf margins incurl-ed at the 16000 ppm. In cucumbers, above 8000 ppm, leaf margins incurled and interveinal chlorosis occurred starting from older leaves before the death of the plant. In snap beans, leaves were dark green at the 2000 and 4000 ppm, while at the 8000 ppm older leaves developed severe burn between veins before the death of the plant. In strawberries, severe mar-ginal burn occurred in older leaves and petals were greenish at the 2000 and 4000 ppm. Blossom-end rot occurred to a high degree at the 1000 ppm and above 8000 ppm in tomatoes, and at the 2000 ppm in pep-pers. Broad beans developed no specific symptoms. 4. With increasing concentration of NaCl, the accumulation of Na in leaves increased almost linearly, except in peppers and snap beans, while Cl accumu-lated linearly in any crop. Cl accumulated in leaves in greater equivalent amounts than Na except in broad beans. Antagonistic relations between Na and other cations, i. e. K, Ca, and Mg, varied with ions or vegetables, and the total amount of these four cations in leaves decreased in peppers and snap beans and increased in the others with the increase of NaCl. The variation in the content of N or P was rather slight as compared with cations and was variable with the vegetable species. There was no definite tendency in the contents of carbohydrates.