Ozone inhibits phloem loading from a transport pool: compartmental efflux analysis in Pima cotton

This paper originates from a presentation at the International Conference on Assimilate Transport and Partitioning, Newcastle, NSW, August 1999 The rate of export of recent photoassimilate from source leaves of Pima cotton (Gossypium barbadense L.) is inhibited by ozone (O3). To characterize these effects on export, source leaves of Pima cotton were exposed to pulses (0.75 h) of O3 (0.0, 0.2, 0.5 and 0.8 L L–1) followed by pulses of 14CO2. Leaves were monitored by gas exchange and with a Geiger–Muller tube, for a sufficient period to characterize carbon assimilation (A) and a rapid and a slower phase of export. Double exponential decay functions (two-compartment model) were fitted and a compartmental analysis conducted. O3 reduced by half the fast rate constant describing export from a transport pool, without affecting the rate constants for transport from or to a storage compartment. Measured soluble sugar contents increased slightly from control concentrations (1.2 g C m–2) by about 5–10% at all O3 concentrations. The calculated soluble sugar content in the transport pool increased from about 200 to 300 mg C m–2 with increasing exposure to O3. The calculated storage pool did not respond to O3 but exceeded measured contents. This discrepancy is attributed to starch deposition and mobilization, which are not considered in the two-compartment model, uncertainties in slower decay parameters, and non-steady-state A induced by O3 exposure. Specific inhibition of rapid efflux suggests oxidant damage at the plasmalemma or plasmodesmata of mesophyll or phloem companion cells, and little effect on the tonoplast. A was affected less than export. Future research should target oxidation of components involved in phloem loading.

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Optimising grapevine summer stress responses and hormonal balance by applying kaolin in two Portuguese Demarcated Regions

OENO One ◽

10.20870/oeno-one.2021.55.1.4502 ◽

2021 ◽

Vol 55 (1) ◽

pp. 207-222

Author(s):

Sara Bernardo ◽

Lia-Tânia Dinis ◽

Ana Luzio ◽

Nelson Machado ◽

Alexandre Gonçalves ◽

...

Keyword(s):

Stress Responses ◽

Environmental Conditions ◽

Sugar Content ◽

Soluble Sugar ◽

Carbon Assimilation ◽

Mitigation Strategies ◽

Growing Seasons ◽

Hormonal Balance ◽

Summer Stress ◽

Grapevine Leaves

In Mediterranean-like climate areas, field-grown grapevines are typically exposed to severe environmental conditions during the summer season, which can negatively impact the sustainability of viticulture. Despite the short-term mitigation strategies available nowadays to cope with climate change, little is known regarding their effectiveness in different demarcated winegrowing regions with differing climate features. Hence, we applied a kaolin suspension (5 %) to Touriga-Franca (TF) and Touriga-Nacional (TN) grapevine varieties located in two Portuguese demarcated regions (Alentejo and Douro) with different mesoclimates to study its effect on the physiological performance, hormonal balance and ABA-related grapevine leaf gene expression during the 2017 and 2018 growing seasons. Data show that 2017 was warmer than 2018 due to the occurrence of two heatwaves in both locations, highlighting the protective effect of kaolin application under severe environmental conditions. In the first study year, at midday, kaolin enhanced water use efficiency (23 % in Douro and 13 % in Alentejo), carbon assimilation rates (PN; 72 % in Douro and 25 % in Alentejo), and the soluble sugar content of grapevine leaves, while decreasing the accumulation of plant growth regulators (ABA, IAA, and SA) during the ripening stage. The results show an up-regulation of ABA biosynthesis-related genes (VvNCED) in TF treated vines from the Douro vineyard mainly in 2017, suggesting an increased stress response under severe summer conditions. Additionally, kaolin triggered the expression of ABA-responsive genes (VvHVA22a and VvSnRK2.6) mainly in TF, indicating different varietal responses to kaolin application under fluctuating periods of summer stress.

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Phosphorus Fluxes in Limnetic Cladocerans: Coupling of Allometry and Compartmental Analysis

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f94-105 ◽

1994 ◽

Vol 51 (5) ◽

pp. 1055-1064 ◽

Cited By ~ 11

Author(s):

Yuan Hua Wen ◽

Alain Vézina ◽

Robert Henry Peters

Keyword(s):

Body Weight ◽

Steady State ◽

Body Size ◽

Time Course ◽

Compartmental Analysis ◽

Compartment Model ◽

Size Dependent ◽

Two Compartment Model ◽

Metabolic Activities ◽

Total P

A size-dependent two-compartment model was developed for estimation of 32P turnover and fluxes by limnetic cladocerans in steady state. After feeding on radioactively labelled food, uniformly labelled animals were fed unlabelled cells and the time course of release of tracer followed. Rates of turnover and size-specific fluxes were subsequently fitted to a two-compartment model. The model predicted that steady-state turnover and size-specific fluxes for 32P excretion declined with body weight and that the exponent of weight did not significantly differ from −0.25, suggesting the relationships between total P turnover or flux rates and body size in cladocerans follow the same allometry observed for other organisms and other metabolic activities. However, rate constants for intercompartmental exchanges declined faster than weight−0.25, indicating that their turnover and flux declined much faster with increasing body size than would be expected from general allometry. Size-specific ingestion and assimilation rates of 32P by cladocerans decreased with increasing body size with a slope of the allometric function similar to −0.25.

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GmFULa improves soybean yield by enhancing carbon assimilation without altering flowering time or maturity

Plant Cell Reports ◽

10.1007/s00299-021-02752-y ◽

2021 ◽

Author(s):

Yanlei Yue ◽

Shi Sun ◽

Jiawen Li ◽

Haidong Yu ◽

Hongxia Wu ◽

...

Keyword(s):

Flowering Time ◽

Sugar Content ◽

Soluble Sugar ◽

Carbon Assimilation ◽

Cell Number ◽

Tissue Cell ◽

Dry Matter Accumulation ◽

Branch Number ◽

Soybean Yield ◽

Control Seed

Abstract Key message GmFULa improved soybean yield by enhancing carbon assimilation. Meanwhile, different from known yield-related genes, it did not alter flowering time or maturity. Abstract Soybean (Glycine max (L.) Merr.) is highly demanded by a continuously growing human population. However, increasing soybean yield is a major challenge. FRUITFULL (FUL), a MADS-box transcription factor, plays important roles in multiple developmental processes, especially fruit and pod development, which are crucial for soybean yield formation. However, the functions of its homologs in soybean are not clear. Here, through haplotype analysis, we found that one haplotype of the soybean homolog GmFULa (GmFULa-H02) is dominant in cultivated soybeans, suggesting that GmFULa-H02 was highly selected during domestication and varietal improvement of soybean. Interestingly, transgenic overexpression of GmFULa enhanced vegetative growth with more biomass accumulated and ultimately increased the yield but without affecting the plant height or changing the flowering time and maturity, indicating that it enhances the efficiency of dry matter accumulation. It also promoted the yield factors like branch number, pod number and 100-seed weight, which ultimately increased the yield. It increased the palisade tissue cell number and the chlorophyll content to promote photosynthesis and increase the soluble sugar content in leaves and fresh seeds. Furthermore, GmFULa were found to be sublocalized in the nucleus and positively regulate sucrose synthases (SUSs) and sucrose transporters (SUTs) by binding with the conserved CArG boxes in their promoters. Overall, these results showed GmFULa promotes the capacity of assimilation and the transport of the resultant assimilates to increase yield, and provided insights into the link between GmFULa and sucrose synthesis with transport-related molecular pathways that control seed yield.

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Effects of lung volume on clearance of solutes from the air spaces of lungs

Journal of Applied Physiology ◽

10.1152/jappl.1988.64.3.1068 ◽

1988 ◽

Vol 64 (3) ◽

pp. 1068-1075 ◽

Cited By ~ 8

Author(s):

B. T. Peterson ◽

H. L. James ◽

J. W. McLarty

Keyword(s):

Human Serum Albumin ◽

Lung Volume ◽

Clearance Rate ◽

Compartmental Analysis ◽

Compartment Model ◽

Lung Inflation ◽

Experimental Animals ◽

Two Compartment Model ◽

Additional Control ◽

Albumin Clearance

Several investigators have shown that the clearance rate of aerosolized 99mTc-labeled diethylenetriamine pentaacetate (DTPA, mol wt = 492, radius = 0.6 nm) from the air spaces of the lungs of humans and experimental animals increases with lung volume. To further investigate this phenomenon we performed a compartmental analysis of the 2-h clearance of DTPA from the lungs of anesthetized sheep using a new method to more accurately correct for the effects of DTPA recirculation. This analysis showed that the DTPA clearance in eight sheep ventilated with zero end-expired pressure was best described by a one-compartment model with a clearance rate of 0.42 ± 0.15%/min. Ventilating eight sheep with an end-expired pressure of 10 cmH2O throughout the study increased the end-expired volume 0.4 ± 0.1 liter BTPS and created a clearance curve that was best described by a two-compartment model. In these sheep 56 ± 16% of the DTPA cleared from the lungs at a rate of 7.9 ± 2.9%/min. The remainder cleared at a rate similar to that measured in the sheep ventilated with zero end-expired pressure (0.35 ± 0.18%/min). Additional control and lung inflation experiments were performed using 99mTc-labeled human serum albumin (mol wt = 66,000, radius = 3.6 nm). In six control sheep ventilated with zero end-expired pressure the albumin clearance was best described by a one-compartment model with a clearance rate of 0.06 ± 0.02%/min. The clearance rate in six sheep with increased lung volume was slightly larger (0.09 ± 0.02, P less than 0.05) but was well described by a one-compartment model.(ABSTRACT TRUNCATED AT 250 WORDS)

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Endophytes Increased Fruit Quality with Higher Soluble Sugar Production in Honeycrisp Apple (Malus pumila)

Microorganisms ◽

10.3390/microorganisms8050699 ◽

2020 ◽

Vol 8 (5) ◽

pp. 699 ◽

Cited By ~ 1

Author(s):

Hyungmin Rho ◽

Victor Van Epps ◽

Soo-Hyung Kim ◽

Sharon L. Doty

Keyword(s):

Nitrogen Fixation ◽

Plant Hormone ◽

Stomatal Density ◽

Sugar Content ◽

Soluble Sugar ◽

Future Research ◽

Hormone Production ◽

Apple Trees ◽

Chlorophyll Content And Fluorescence ◽

Soluble Sugar Content

Endophytes are fungi, bacteria, or yeast symbionts that live in the intercellular spaces or vascular tissues of host plants. Investigations indicate that endophytes isolated from the Salicaceae family (Populus and Salix) hosts provide several benefits that promote plant growth, including but not limited to di-nitrogen fixation, plant hormone production, nutrient acquisition, stress tolerance, and defense against phytopathogens. In exchange, the microorganisms receive domicile and photosynthates. Considering the known characteristics of nitrogen fixation and plant hormone production, we hypothesized that apple trees grown under nitrogen-limited conditions would show improved biometrics with endophyte inoculation. Our research objectives were to investigate the endophyte effects on plant physiology and fruiting. We examined these effects through ecophysiology metrics involving rates of photosynthesis, stomatal conductance and density, transpiration, biomass accretion, chlorophyll content and fluorescence, and fruit soluble sugar content and biomass. Our results showed evidence of the endophytes’ colonization in apple trees, decreased stomatal density, delayed leaf senescence, and increased lateral root biomass with endophytes. A highlight of the findings was a significant increase in both fruit soluble sugar content and biomass. Future research into the mechanistic underpinnings of this phenomenon stands to offer novel insights on how microbiota may alter carbohydrate metabolism under nitrogen-deficient conditions.

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Surfactant disaturated phosphatidylcholine kinetics in infants with bronchopulmonary dysplasia measured with stable isotopes and a two-compartment model

Journal of Applied Physiology ◽

10.1152/japplphysiol.01423.2004 ◽

2005 ◽

Vol 99 (1) ◽

pp. 323-329 ◽

Cited By ~ 17

Author(s):

Paola E. Cogo ◽

Gianna Maria Toffolo ◽

Antonina Gucciardi ◽

Arianna Benetazzo ◽

Claudio Cobelli ◽

...

Keyword(s):

Bronchopulmonary Dysplasia ◽

Gestational Age ◽

Decay Curve ◽

Compartmental Analysis ◽

Compartment Model ◽

Study Groups ◽

Gas Chromatography Mass Spectrometry ◽

Isotope Tracer ◽

Two Compartment Model ◽

Intracellular Storage

We previously found a shorter surfactant disaturated phosphatidylcholine palmitate (DSPC-PA) half-life in infants with bronchopulmonary dysplasia (BPD) by using a single stable isotope tracer and simple formulas based on a one-exponential fit of the final portion of the enrichment decay curve. The aim of this study was to apply noncompartmental and compartmental analysis on the entire enrichment decay curve of DSPC-PA and to compare the kinetic data with our previous results. We analyzed 10 preterm newborns with BPD (gestational age 26 ± 0.6 wk, weight 777 ± 199 g) and 6 controls (gestational age 26 ± 1.4 wk, weight 787 ± 259 g). All took part in our previous study. Endotracheal 13C-labeled dipalmitoyl phosphatidylcholine was administered, and the 13C-enrichment of surfactant DSPC-PA was measured from serial tracheal aspirates by gas chromatography-mass spectrometry. Noncompartmental and compartmental models were numerically identified from the tracer-to-tracee ratio and kinetic parameters related to the accessible (pool accessible to sampling, likely to be the lung alveolar pool) and to the nonaccessible pools (pools not accessible to samplings, likely to be the intracellular storage pool) were estimated in the two study groups. Comparison was performed by Mann-Whitney test. A two-compartment model provided the most reliable assessment of DSPC-PA kinetics. In BPD vs. controls, mean ± SE residence time of DSPC-PA in the accessible was 17.5 ± 2.6 vs. 32.2 ± 6.4 h ( P < 0.05), whereas it was 49.7 ± 3.5 vs. 54.4 ± 3.9 h (NS, not significant) in the nonaccessible pool; DSPC-PA recycling was 0.26 ± 0.05 vs. 0.43 ± 0.04% (NS), respectively. A two-compartment model of surfactant DSPC-PA kinetics allowed a thorough assessment of DSPC-PA kinetics, including masses, synthesis, and fluxes between pools. The most important findings of this study are that in BPD infants DSPC-PA loss from the alveolar pool was higher and recycling through the intracellular pool lower than in controls.

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Effects of Abscisic Acid on ex vitro Acclimatization of Aronia arbutifolia (L.) Pers.

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.121.1.101 ◽

1996 ◽

Vol 121 (1) ◽

pp. 101-104 ◽

Cited By ~ 8

Author(s):

Wilfredo Colón-Guasp ◽

Terril A. Nell ◽

Michael E. Kane ◽

James E. Barrett

Keyword(s):

Abscisic Acid ◽

Shoot Growth ◽

Starch Content ◽

Sugar Content ◽

Soluble Sugar ◽

Carbon Assimilation ◽

Stage Iii ◽

Photon Flux ◽

Ex Vitro

The use of abscisic acid (ABA) as an in vitro prehardening treatment to enhance ex vitro acclimatization of Stage III Aronia arbutifolia plantlets was explored. Effects of ABA (0-4 mg·liter-1) pretreatment on ex vitro shoot growth, leaf carbon assimilation (LCA) and nonstructural carbohydrate content were evaluated during plantlet acclimatization under two photosynthetic photon flux (PPF) levels (450 and 650 μmol·m-2·s-1). Stage III plantlets rooted in the presence of ABA exhibited both shoot growth inhibition and transient negative LCA rates at time of transfer ex vitro. Regardless of treatment, maximum LCA rates were achieved by day 20 post-transplant. Pretreatment with ABA had no effect on stem or leaf starch content at time of transplant, however, leaf and stem soluble sugar content was higher in ABA treated plantlets than controls. Further suppression of shoot growth and alteration in the pattern of stem starch utilization occurred at the higher irradiance level. These results indicate that ABA pretreatments provide no physiological advantage that would facilitate ex vitro acclimatization of Aronia plantlets.

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Morphological, Physiological and Biochemical Responses of Poplar Plants to Drought Stress

Journal of AgriSearch ◽

10.21921/jas.5.3.7 ◽

2018 ◽

Vol 5 (03) ◽

Author(s):

ARADHNA KUMARI ◽

IM KHAN ◽

ANIL KUMAR SINGH ◽

SANTOSH KUMAR SINGH

Keyword(s):

Water Stress ◽

Drought Stress ◽

Biochemical Parameters ◽

Sugar Content ◽

Soluble Sugar ◽

Field Capacity ◽

Drought Event ◽

Total Biomass ◽

Biochemical Responses ◽

Physiological And Biochemical

Poplar clone Kranti was selected to assess the morphological, physiological and biochemical responses under drought at different levels of water stress, as it is a common clone used to be grown in Uttarakhand for making paper and plywood. The cuttings of Populus deltoides L. (clone Kranti) were exposed to four different watering regimes (100, 75, 50 and 25% of the field capacity) and changes in physiological and biochemical parameters related with drought tolerance were recorded. Alterations in physiological (i.e. decrease in relative water content) and biochemical parameters (i.e. increase in proline and soluble sugar content and build-up of malondialdehyde by-products) occurred in all the three levels of water stress, although drought represented the major determinant. Drought treatments (75%, 50% and 25% FC) decreased plant height, radial stem diameter, harvest index, total biomass content and RWC in all the three watering regimes compared to control (100% FC). Biochemical parameters like proline, soluble sugar and MDA content increased with severity and duration of stress, which helped plants to survive under severe stress. It was analyzed that for better wood yield poplar seedlings should avail either optimum amount of water (amount nearly equal to field capacity of soil) or maximum withdrawal up to 75% of field capacity up to seedling establishment period (60 days). Furthermore, this study manifested that acclimation to drought stress is related with the rapidity, severity, and duration of the drought event of the poplar species.

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Effects of cadmium stress on growth and physiological characteristics of sassafras seedlings

Scientific Reports ◽

10.1038/s41598-021-89322-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Hongyi Zhao ◽

Juelan Guan ◽

Qing Liang ◽

Xueyuan Zhang ◽

Hongling Hu ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Sugar Content ◽

Soluble Sugar ◽

Cadmium Concentration ◽

Cadmium Stress ◽

Proline Content ◽

Physiological Characteristics ◽

Control Treatment ◽

Gas Exchange Parameters ◽

Photosynthetic Gas Exchange

AbstractThe effects of cadmium stress on the growth and physiological characteristics of Sassafras tzumu Hemsl. were studied in pot experiments. Five Cd levels were tested [CT(Control Treatment) : 0 mg/kg, Cd5: 5 mg/kg, Cd20: 20 mg/kg, Cd50: 50 mg/kg, and Cd100: 100 mg/kg]. The growth and physiological characteristics of the sassafras seedlings in each level were measured. The results showed that soil Cd had negative influences on sassafras growth and reduced the net growth of plant height and the biomass of leaf, branch and root. Significant reductions were recorded in root biomass by 18.18%(Cd5), 27.35%(Cd20), 27.57%(Cd50) and 28.95%(Cd100). The contents of hydrogen peroxide decreased first then increased while malondialdehyde showed the opposite trend with increasing cadmium concentration. Decreases were found in hydrogen peroxide contents by 10.96%(Cd5), 11.82%(Cd20) and 7.02%(Cd50); increases were found in malondialdehyde contents by 15.47%(Cd5), 16.07%(Cd20) and 7.85%(Cd50), indicating that cadmium stress had a certain effect on the peroxidation of the inner cell membranes in the seedlings that resulted in damage to the cell membrane structure. Superoxide dismutase activity decreased among treatments by 17.05%(Cd5), 10,68%(Cd20), 20.85%(Cd50) and 8.91%(Cd100), while peroxidase activity increased steadily with increasing cadmium concentration; these results suggest that peroxidase is likely the main protective enzyme involved in the reactive oxygen removal system in sassafras seedlings. Upward trends were observed in proline content by 90.76%(Cd5), 74.36%(Cd20), 99.73%(Cd50) and 126.01%(Cd100). The increase in proline content with increasing cadmium concentration indicated that cadmium stress induced proline synthesis to resist osmotic stress in the seedlings. Compared to that in CT, the soluble sugar content declined under the different treatments by 32.84%(Cd5), 5.85%(Cd20), 25.55%(Cd50) and 38.69%(Cd100). Increases were observed in the soluble protein content by 2.34%(Cd5), 21.36%(Cd20), 53.15%(Cd50) and 24.22%(Cd100). At different levels of cadmium stress, the chlorophyll content in the seedlings first increased and then decreased, and it was higher in the Cd5 and Cd20 treatments than that in the CT treatment. These results reflected that cadmium had photosynthesis-promoting effects at low concentrations and photosynthesis-suppressing effects at high concentrations. The photosynthetic gas exchange parameters and photosynthetic light-response parameters showed downward trends with increasing cadmium concentration compared with those in CT; these results reflected the negative effects of cadmium stress on photosynthesis in sassafras seedlings.

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