scholarly journals Two distinct strategies of cotton and soybean differing in leaf movement to perform photosynthesis under drought in the field

2011 ◽  
Vol 38 (7) ◽  
pp. 567 ◽  
Author(s):  
Ya-Li Zhang ◽  
Yuan-Yuan Hu ◽  
Hong-Hai Luo ◽  
Wah Soon Chow ◽  
Wang-Feng Zhang
Keyword(s):  
Electron Flow ◽  
Co2 Assimilation ◽  
Leaf Nitrogen ◽  
Light Energy ◽  
Leaf Movement ◽  
Lower Maximum ◽  
The Difference ◽  
Soybean Leaves ◽  
Transport Flux ◽  
Psii Quantum Yield

This paper reports an experimental test of the hypothesis that cotton and soybean differing in leaf movement have distinct strategies to perform photosynthesis under drought. Cotton and soybean were exposed to two water regimes: drought stressed and well watered. Drought-stressed cotton and soybean had lower maximum CO2 assimilation rates than well-watered (control) plants. Drought reduced the light saturation point and photorespiration of both species – especially in soybean. Area-based leaf nitrogen decreased in drought-stressed soybean but increased in drought-stressed cotton. Drought decreased PSII quantum yield (ΦPSII) in soybean leaves, but increased ΦPSII in cotton leaves. Drought induced an increase in light absorbed by the PSII antennae that is dissipated thermally via ΔpH- and xanthophylls-regulated processes in soybean leaves, but a decrease in cotton leaves. Soybean leaves appeared to have greater cyclic electron flow (CEF) around PSI than cotton leaves and drought further increased CEF in soybean leaves. In contrast, CEF slightly decreased in cotton under drought. These results suggest that the difference in leaf movement between cotton and soybean leaves gives rise to different strategies to perform photosynthesis and to contrasting photoprotective mechanisms for utilisation or dissipation of excess light energy. We suggest that soybean preferentially uses light-regulated non-photochemical energy dissipation, which may have been enhanced by the higher CEF in drought-stressed leaves. In contrast, cotton appears to rely on enhanced electron transport flux for light energy utilisation under drought, for example, in enhanced nitrogen assimilation.

Inherent nitrogen deficiency in Pistacia lentiscus preferentially affects photosystem I: a seasonal field study

2011 ◽  
Vol 38 (11) ◽  
pp. 848 ◽  
Author(s):  
Constantinos Nikiforou ◽  
Yiannis Manetas
Keyword(s):  
Electron Flow ◽  
Nitrogen Deficiency ◽  
Co2 Assimilation ◽  
Leaf Nitrogen ◽  
Field Conditions ◽  
Quantum Yields ◽  
Winter Period ◽  
Pistacia Lentiscus ◽  
Total Electron ◽  
Low Nitrogen

Although it is widely documented that CO2 assimilation rates are positively correlated with leaf nitrogen, corresponding studies on a link between this nutrient and photosynthetic light reactions are scarce, especially under natural field conditions. In this investigation, we exploited natural variation in the nitrogen content of mature leaves of Pistacia lentiscus L. (mastic tree) in conjunction with fast chlorophyll a fluorescence rise (the OJIP curves) analysed according to the ‘JIP test’, as this was recently modified to allow for the assessment of events in or around PSI. The results depended on the sampling season, with low nitrogen leaves displaying lower efficiencies for electron flow from intermediate carriers to final PSI acceptors, and lower relative pool sizes of these acceptors, both during the autumn and winter. However, parameters related to the PSII) activity (i.e. quantum yields for photon trapping and electron flow along PSII and the efficiency of a trapped exciton to move an electron from the first plastoquoinone electron acceptor of PSII to intermediate carriers) were limited by low nitrogen only during the winter period. As a result, parameters like the quantum yield of total electron flow along both photosystems as well as the total photosynthetic performance index (PItotal) were positively correlated with leaf nitrogen independently of the season. We conclude that nitrogen deficiency under field conditions preferentially affects PSI activity while the effects on PSII are evident only during the stressful period of the year.

The effect of low sludge age on wastewater fractionation (SS, SI)

2003 ◽  
Vol 47 (11) ◽  
pp. 203-209 ◽  
Author(s):  
S. Haider ◽  
K. Svardal ◽  
P.A. Vanrolleghem ◽  
H. Kroiss
Keyword(s):  
Activated Sludge ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
The Other ◽  
Second Stage ◽  
Lower Maximum ◽  
The Difference ◽  
Selection Of ◽  
Activated Sludge Systems ◽  
Raw Wastewater

In lab-scale experiments at the 2-stage activated sludge pilot plant of Vienna's central WWTP it is shown that the wastewater soluble COD concentration, which is inert to a sludge with SRT < 1 d (SIA) is about double compared to the SI concentration in sludge with SRT > 10 d (SIB). Unexpectedly the ratio of SIA/SIB is independent of the sludge age between SRTs of 0.4 and 1.0 days. The difference between the two SI fractions is soluble COD that is readily biodegradable by the sludge with SRT > 10 d. However, it is degraded at a lower maximum growth rate. These results comply with earlier results gained with different methods and at different WWTPs. It is hypothesised that very low sludge ages result in a selection of fast growing bacteria, which can utilise only part of the SS in the raw wastewater. The other part of SS therefore remains in the wastewater and can thus be utilised for enhanced denitrification in the second stage. It is still unknown beyond which sludge age the soluble inert COD SIA starts to decrease, finally reaching the value SIB for low loaded systems (SRT > 5 days). From this point on SI and SS are assumed only to depend on the wastewater composition and not on the sludge age. The assumption of the Activated Sludge Model No.1 that the biodegradable fractions can be modelled as a single substrate and by a single removal kinetic (one Monod term) appears not to be applicable for low sludge ages. Some suggestions for mathematical modelling, design and operation of 2-stage activated sludge systems are given.

scholarly journals Exogenous Abscisic Acid Can Influence Photosynthetic Processes in Peas through a Decrease in Activity of H+-ATP-ase in the Plasma Membrane

Biology ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 324
Author(s):  
Lyubov Yudina ◽  
Ekaterina Sukhova ◽  
Oksana Sherstneva ◽  
Marina Grinberg ◽  
Maria Ladeynova ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Abscisic Acid ◽  
Heat Tolerance ◽  
Electron Flow ◽  
Co2 Assimilation ◽  
Resting Potential ◽  
Electrical Signals ◽  
Exogenous Aba ◽  
Pam Fluorometer ◽  
Photosynthetic Responses

Abscisic acid (ABA) is an important hormone in plants that participates in their acclimation to the action of stressors. Treatment by exogenous ABA and its synthetic analogs are a potential way of controlling the tolerance of agricultural plants; however, the mechanisms of influence of the ABA treatment on photosynthetic processes require further investigations. The aim of our work was to investigate the participation of inactivation of the plasma membrane H+-ATP-ase on the influence of ABA treatment on photosynthetic processes and their regulation by electrical signals in peas. The ABA treatment of seedlings was performed by spraying them with aqueous solutions (10−5 M). The combination of a Dual-PAM-100 PAM fluorometer and GFS-3000 infrared gas analyzer was used for photosynthetic measurements; the patch clamp system on the basis of a SliceScope Pro 2000 microscope was used for measurements of electrical activity. It was shown that the ABA treatment stimulated the cyclic electron flow around photosystem I and decreased the photosynthetic CO2 assimilation, the amplitude of burning-induced electrical signals (variation potentials), and the magnitude of photosynthetic responses relating to these signals; in contrast, treatment with exogenous ABA increased the heat tolerance of photosynthesis. An investigation of the influence of ABA treatment on the metabolic component of the resting potential showed that this treatment decreased the activity of the H+-ATP-ase in the plasma membrane. Inhibitor analysis using sodium orthovanadate demonstrated that this decrease may be a mechanism of the ABA treatment-induced changes in photosynthetic processes, their heat tolerance, and regulation by electrical signals.

scholarly journals Estimating leaf nitrogen concentration based on the combination with fluorescence spectrum and first-derivative

2020 ◽  
Vol 7 (2) ◽  
pp. 191941
Author(s):  
Jian Yang ◽  
Lin Du ◽  
Wei Gong ◽  
Shuo Shi ◽  
Jia Sun
Keyword(s):  
Fluorescence Spectrum ◽  
Nitrogen Concentration ◽  
Principal Component ◽  
Laser Induced Fluorescence ◽  
Leaf Nitrogen ◽  
Leaf Nitrogen Concentration ◽  
Growth Status ◽  
First Derivative ◽  
Fluorescence Characteristics ◽  
The Difference

Leaf nitrogen concentration (LNC) is a major indicator in the estimation of the crop growth status which has been diffusely applied in remote sensing. Thus, it is important to accurately obtain LNC by using passive or active technology. Laser-induced fluorescence can be applied to monitor LNC in crops through analysing the changing of fluorescence spectral information. Thus, the performance of fluorescence spectrum (FS) and first-derivative fluorescence spectrum (FDFS) for paddy rice (Yangliangyou 6 and Manly Indica) LNC estimation was discussed, and then the proposed FS + FDFS was used to monitor LNC by multivariate analysis. The results showed that the difference between FS ( R 2 = 0.781, s.d. = 0.078) and FDFS ( R 2 = 0.779, s.d. = 0.097) for LNC estimation by using the artificial neural network is not obvious. The proposed FS + FDFS can improved the accuracy of LNC estimation to some extent ( R 2 = 0.813, s.d. = 0.051). Then, principal component analysis was used in FS and FDFS, and extracted the main fluorescence characteristics. The results indicated that the proposed FS + FDFS exhibited higher robustness and stability for LNC estimation ( R 2 = 0.851, s.d. = 0.032) than that only using FS ( R 2 = 0.815, s.d. = 0.059) or FDFS ( R 2 = 0.801, s.d. = 0.065).

scholarly journals Flagellin Glycosylation Island in Pseudomonas syringae pv. glycinea and Its Role in Host Specificity

2003 ◽  
Vol 185 (22) ◽  
pp. 6658-6665 ◽  
Author(s):  
Kasumi Takeuchi ◽  
Fumiko Taguchi ◽  
Yoshishige Inagaki ◽  
Kazuhiro Toyoda ◽  
Tomonori Shiraishi ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Posttranslational Modification ◽  
Hypersensitive Reaction ◽  
Amino Acid Sequences ◽  
Open Reading Frames ◽  
Tobacco Leaves ◽  
Flagellin Glycosylation ◽  
The Difference ◽  
Soybean Leaves ◽  
Reading Frames

ABSTRACT The deduced amino acid sequences of the flagellins of Pseudomonas syringae pv. tabaci and P. syringae pv. glycinea are identical; however, their abilities to induce a hypersensitive reaction are clearly different. The reason for the difference seems to depend on the posttranslational modification of the flagellins. To investigate the role of this posttranslational modification in the interactions between plants and bacterial pathogens, we isolated genes that are potentially involved in the posttranslational modification of flagellin in P. syringae pv. glycinea (glycosylation island); then defective mutants with mutations in these genes were generated. There are three open reading frames in the glycosylation island, designated orf1, orf2, and orf3. orf1 and orf2 encode putative glycosyltransferases, and mutants with defects in these open reading frames, Δorf1 and Δorf2, secreted nonglycosylated and slightly glycosylated flagellins, respectively. Inoculation tests performed with these mutants and original nonhost tobacco leaves revealed that Δorf1 and Δorf2 could grow on tobacco leaves and caused symptom-like changes. In contrast, these mutants failed to cause symptoms on original host soybean leaves. These data indicate that putative glycosyltransferases encoded in the flagellin glycosylation island are strongly involved in recognition by plants and could be the specific determinants of compatibility between phytopathogenic bacteria and plant species.

scholarly journals Heterophyllous Shoots of Japanese Larch Trees: The Seasonal and Yearly Variation in CO2 Assimilation Capacity of the Canopy Top with Changing Environment

Plants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1278
Author(s):  
Satoshi Kitaoka ◽  
Qu Laiye ◽  
Yoko Watanabe ◽  
Makoto Watanabe ◽  
Toshihiro Watanabe ◽  
...  
Keyword(s):  
Seasonal Change ◽  
High Growth ◽  
Co2 Assimilation ◽  
High Growth Rate ◽  
Japanese Larch ◽  
Leaf Mass Per Area ◽  
Larix Kaempferi ◽  
Yearly Variation ◽  
The Difference ◽  
Assimilation Capacity

Japanese larch (Larix kaempferi = L. leptolepis) is often characterized by its high growth rate with heterophyllous shoots, but the functional differences of heterophyllous shoots still remain unclear. Recently, abrupt high temperature and drought during spring induced high photosynthetic rate via change in leaf morphology of the deciduous habit. In order to reveal the photosynthetic characteristics of both short and long-shoot needles of sunny canopy of the larch trees using a canopy tower, we calculated the seasonal change of gas exchange characters and leaf mass per area (LMA) and foliar nitrogen content (N) of heterophyllous needles: short and long-shoot needles over 3 years. No marked difference in light-saturated photosynthetic rates (Psat) was observed between short and long shoots after leaf maturation to yellowing, although the difference was obvious in a specific year, which only shows that seasonal change in temperature and soil moisture determines the in situ photosynthetic capacity of needles. The large annual and seasonal variations in Psat in both shoots were found to be mainly determined by climatic variations, while shoot types determined the strategy of their photosynthetic N utilization as well as the stomatal regulation.

scholarly journals Differences in gait stability, trunk and foot accelerations between healthy young and older women

2021 ◽  
Author(s):  
Yuge Zhang ◽  
Xinglong Zhou ◽  
Mirjam Pijnappels ◽  
Sjoerd M. Bruijn
Keyword(s):  
Inertial Sensors ◽  
Age Groups ◽  
Vertical Acceleration ◽  
Gait Stability ◽  
Exercise Habits ◽  
Young Females ◽  
Age Related ◽  
Spatiotemporal Parameters ◽  
Lower Maximum ◽  
The Difference

AbstractBackgroundGait stability has been shown to be affected by age-related mobility problems, but exercise habits may reduce decline in gait stability. Our aim was to evaluate the variability and stability of feet and trunk between older healthy females and young females using inertial sensors.Method20 older females (OF; mean age 68.4, SD 4.1 years) and 18 young females (YF; mean age 22.3, SD 1.7 years) were asked to walk at their preferred speed, while kinematics were measured using inertial sensors on heels and lower back. Spatiotemporal parameters, acceleration characteristics and their variability, as well as trunk stability as assessed using the local divergence exponent (LDE), were calculated and compared between age groups with two-way ANOVA analyses.ResultsTrunk-foot vertical acceleration attenuation, foot vertical acceleration maximum and amplitude, as well as their variability were significantly smaller in OF than in YF. In contrast, for trunk mediolateral acceleration amplitude, vertical acceleration maximum and amplitude, as well as their variability were significantly larger in OF than in YF. Moreover, OF showed lower stability (i.e. higher LDE values) in ML acceleration, ML and VT angular velocity on the trunk.ConclusionThese findings suggest that healthy older females had a lower maximum toe clearance so that were more likely to trip. Moreover, the acceleration of trunk was sensitive to the difference between healthy older and young females, both in variability and stability. Combined, although older adults had exercise habits, our metrics indicate that they were less stable, which may increase the risk of tripping and balance loss.

scholarly journals Photorespiration Alleviates Photoinhibition of Photosystem I under Fluctuating Light in Tomato

Plants ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 195
Author(s):  
Qi Shi ◽  
Hu Sun ◽  
Stefan Timm ◽  
Shibao Zhang ◽  
Wei Huang
Keyword(s):  
Electron Transport ◽  
Photosystem I ◽  
Light Stress ◽  
Co2 Assimilation ◽  
Photosynthetic Performance ◽  
High Light ◽  
Sudden Increase ◽  
Fluctuating Light ◽  
Significant Difference ◽  
The Difference

Fluctuating light (FL) is a typical natural light stress that can cause photodamage to photosystem I (PSI). However, the effect of growth light on FL-induced PSI photoinhibition remains controversial. Plants grown under high light enhance photorespiration to sustain photosynthesis, but the contribution of photorespiration to PSI photoprotection under FL is largely unknown. In this study, we examined the photosynthetic performance under FL in tomato (Lycopersicon esculentum) plants grown under high light (HL-plants) and moderate light (ML-plants). After an abrupt increase in illumination, the over-reduction of PSI was lowered in HL-plants, resulting in a lower FL-induced PSI photoinhibition. HL-plants displayed higher capacities for CO2 fixation and photorespiration than ML-plants. Within the first 60 s after transition from low to high light, PSII electron transport was much higher in HL-plants, but the gross CO2 assimilation rate showed no significant difference between them. Therefore, upon a sudden increase in illumination, the difference in PSII electron transport between HL- and ML-plants was not attributed to the Calvin–Benson cycle but was caused by the change in photorespiration. These results indicated that the higher photorespiration in HL-plants enhanced the PSI electron sink downstream under FL, which mitigated the over-reduction of PSI and thus alleviated PSI photoinhibition under FL. Taking together, we here for the first time propose that photorespiration acts as a safety valve for PSI photoprotection under FL.

scholarly journals CO2 Assimilation, Photosynthetic Enzymes, and Carbohydrates of Grape Leaves (Vitis labrusca L. cv. Concord) in Response to Iron Supply

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 826D-827
Author(s):  
Brandon R. Smith* ◽  
Li-Song Chen ◽  
Lailiang Cheng
Keyword(s):  
Calvin Cycle ◽  
Sucrose Phosphate Synthase ◽  
Co2 Assimilation ◽  
Carbon Export ◽  
Photosynthetic Enzymes ◽  
Hydroxyphenylacetic Acid ◽  
Key Enzyme ◽  
The Difference ◽  
One Year ◽  
Assimilation Capacity

Own-rooted one-year-old `Concord' grapevines were fertigated twice weekly for 11 weeks with 1, 10, 20, 50, OR 100 μmol iron (Fe) from ferric ethylenediamine di (o-hydroxyphenylacetic) acid in a complete nutrient solution. As Fe supply increased, leaf total Fe content did not change, whereas active Fe (extracted by 2, 2'-dipyridyl) and total chlorophyll content increased curvilinearly. CO2 assimilation and stomatal conductance increased curvilinearly with increasing active Fe, whereas intercellular CO2 concentrations decreased linearly. Activities of key Calvin cycle enzymes, Rubisco, NADP-glyceraldehyde-3-phosphate dehydrogenase, phosphoribulokinase, stromal fructose-1,6-bisphosphatase (FBPase), and a key enzyme in sucrose synthesis, cytosolic FBPase, all increased linearly with increasing active Fe. No difference was found in the activities of ADP-glucose pyrophosphorylase and sucrose phosphate synthase of leaves between the lowest and the highest treatments, whereas slightly lower activities were observed in the middle Fe treatments. Content of 3-phosphoglycerate increased curvilinearly with increased active Fe, whereas glucose-6-phosphate and fructose-6-phosphate did not change. Glucose, fructose, sucrose, starch, and total non-structural carbohydrates at both dusk and pre-dawn increased with increasing active Fe. Carbon export from starch breakdown during the night, calculated as the difference between dusk and predawn levels, increased as active Fe increased. In conclusion, Fe limitation reduces the activities of Rubisco and other photosynthetic enzymes, and hence CO2 assimilation capacity. Fe-deficient grapevines have lower concentrations of non-structural carbohydrates in source leaves, and therefore, are source limited.

scholarly journals Genetic variation for photosynthetic capacity and efficiency in spring wheat

2019 ◽  
Vol 71 (7) ◽  
pp. 2299-2311 ◽  
Author(s):  
Viridiana Silva-Pérez ◽  
Joanne De Faveri ◽  
Gemma Molero ◽  
David M Deery ◽  
Anthony G Condon ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Stomatal Conductance ◽  
Photosynthetic Capacity ◽  
Genotypic Variation ◽  
Genotypic Diversity ◽  
Dry Mass ◽  
Co2 Assimilation ◽  
Leaf Nitrogen ◽  
Yield Potential

Abstract One way to increase yield potential in wheat is screening for natural variation in photosynthesis. This study uses measured and modelled physiological parameters to explore genotypic diversity in photosynthetic capacity (Pc, Rubisco carboxylation capacity per unit leaf area at 25 °C) and efficiency (Peff, Pc per unit of leaf nitrogen) in wheat in relation to fertilizer, plant stage, and environment. Four experiments (Aus1, Aus2, Aus3, and Mex1) were carried out with diverse wheat collections to investigate genetic variation for Rubisco capacity (Vcmax25), electron transport rate (J), CO2 assimilation rate, stomatal conductance, and complementary plant functional traits: leaf nitrogen, leaf dry mass per unit area, and SPAD. Genotypes for Aus1 and Aus2 were grown in the glasshouse with two fertilizer levels. Genotypes for Aus3 and Mex1 experiments were grown in the field in Australia and Mexico, respectively. Results showed that Vcmax25 derived from gas exchange measurements is a robust parameter that does not depend on stomatal conductance and was positively correlated with Rubisco content measured in vitro. There was significant genotypic variation in most of the experiments for Pc and Peff. Heritability of Pc reached 0.7 and 0.9 for SPAD. Genotypic variation and heritability of traits show that there is scope for these traits to be used in pre-breeding programmes to improve photosynthesis with the ultimate objective of raising yield potential.

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