scholarly journals Leaf application of chitosan and physiological evaluation of maize hybrids contrasting for drought tolerance under water restriction

2020 ◽  
Vol 80 (3) ◽  
pp. 631-640 ◽  
Author(s):  
V. Veroneze-Júnior ◽  
M. Martins ◽  
L. Mc Leod ◽  
K. R. D. Souza ◽  
P. R. Santos-Filho ◽  
...  
Keyword(s):  
Electron Transport Rate ◽  
Photochemical Quenching ◽  
Water Restriction ◽  
Maize Crop ◽  
Maize Hybrids ◽  
Productivity Losses ◽  
Maize Genotypes ◽  
Physiological Evaluation ◽  
Non Photochemical Quenching ◽  
Tolerant Genotype

Abstract It is a fact that the regions that cultivate the most maize crop do not have fully adequate technologies to measure productivity losses caused by irregularities in water availability. The objective of this study was to evaluate the physiological characteristics of maize hybrids tolerant (DKB 390) and sensitive (BRS 1030) to drought, at V5 growth stage and under water restriction, in order to understand the mechanisms involved in the induction of tolerance to drought by chitosan in contrasting maize genotypes. Plants were cultivated in pots at a greenhouse, and chitosan 100 ppm was applied by leaf spraying. The water restriction was imposed for 10 days and then leaf gaseous exchange and chlorophyll fluorescence were evaluated. The tolerant hybrid (DKB 390) showed higher photosynthesis, stomatal conductance, carboxylation efficiency, electron transport rate, and non-photochemical quenching when chitosan was used. Plants from tolerant genotype treated with chitosan were more tolerant to water stress because there were more responsive to the biopolymer.

scholarly journals Water Requirements and Drought Tolerance of Bedding Plants

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1115D-1115
Author(s):  
Krishna S. Nemali ◽  
Marc W. van Iersel
Keyword(s):  
Drought Tolerance ◽  
Gas Phase ◽  
Electron Transport Rate ◽  
Photochemical Quenching ◽  
Response Curves ◽  
Water Requirements ◽  
Bedding Plants ◽  
Species Analysis ◽  
Non Photochemical Quenching ◽  
Mesophyll Resistance

Optimal substrate volumetric water content (θ) and drought tolerance of impatiens, petunia, salvia, and vinca were investigated by growing plants under four constant levels of θ (0.09, 0.15, 0.22, and 0.32 m3·m-3). Gas exchange, quantum efficiency (ΦPSII), electron transport rate (ETR), non-photochemical quenching (NPQ), and leaf water potential (ϒ) were measured for all species, and response of photosynthesis (Pn) to internal CO2 concentration (Ci) was studied in petunia and salvia. Leaf photosynthesis (Pmax) was highest at a θ of 0.22 m3·m-3 for all species and did not differ between a θ of 0.15 and 0.22 m3·m-3 for vinca and petunia. The Pn-Ci response curves for petunia were almost identical at a θ of 0.22 and 0.15 m3·m-3. Regardless of species, ETR and ΦPSII were highest and NPQ was lowest at a θ of 0.22 m3·m-3. Based on these results, a θ of 0.22 m3·m-3 for salvia and impatiens and a slightly lower θ of 0.15 m3·m-3 for vinca and petunia, is optimal. Mean osmotic potential in all treatments was lower in vinca and salvia and resulted in higher turgor potential in these species than other species. Analysis of Pn-Ci response curves indicated that Pn at a θ of 0.09 m3·m-3 was limited by both gas phase (stomatal and boundary layer) and non-gas phase (mesophyll) resistance to CO2 transfer in salvia. At the lowest θ level, Pn in petunia was only limited by gas phase resistance, indicating that absence of mesophyll resistance during drought may play a role in the drought tolerance of petunia.

scholarly journals Physiological and microclimatic consequences of variation in agricultural management of maize

2020 ◽  
Vol 99 (1) ◽  
pp. 132-148
Author(s):  
Rosa Guadalupe Pérez-Hernández ◽  
Manuel Jesus Cach-Pérez ◽  
Rosaura Aparacio-Fabre ◽  
Hans Van der Wal ◽  
Ulises Rodríguez-Robles
Keyword(s):  
Electron Transport ◽  
Soil Temperature ◽  
Electron Transport Rate ◽  
Agricultural Management ◽  
Transport Rate ◽  
Management Systems ◽  
Photochemical Quenching ◽  
Physiological Performance ◽  
Maize Plants ◽  
Non Photochemical Quenching

Background: Maize is cultivated under different agricultural management systems, which influence the ecological dynamics of the crop, and therefore the physiology of the plant. Questions: What is the effect of different agricultural management on the microclimate and the physiology of maize plants? Studied species: Zea mays L. Study site and dates: Nacajuca, Tabasco, Mexico; January to April 2017. Methods: Physiological performance of maize plants and microclimatic variation in the crop area was characterized under three management systems: maize monoculture, maize-bean, and maize-bean-squash intercropping. Each treatment was established in three 100 m2 plots (300 m2 per treatment). Four measurements were taken between days 33 and 99 after maize sowing, to characterize five microclimatic parameters (relative air humidity, air and soil temperature, vapor-pressure deficit and soil volumetric water content) and nine physiological parameters (photosynthesis, transpiration, water use efficiency, stomatal conductance, electron transport rate, quantum efficiency of photosystem II, non-photochemical quenching, foliar water potential and chlorophyll content). Results: Maximum soil temperature was up to 4.4 ºC less in the maize-bean system than in the monoculture at 15:00 h; soil in the maize-bean-squash intercropping retained up to 45 % more water than the monoculture throughout the day. Photosynthesis and electron transport rate in the maize-bean intercropping was up to 32 % higher than in the monoculture. The highest non-photochemical quenching and transpiration rate were observed in the maize-bean-squash system. Conclusions: The maize-bean and maize-bean-squash combination provides maize plants with lower soil temperature and higher water availability, allowing them better physiological performance compared to monoculture.

scholarly journals Photosynthetic performance of two maize genotypes as affected by chilling stress

2011 ◽  
Vol 51 (No. 5) ◽  
pp. 206-212 ◽  
Author(s):  
K. Kosová ◽  
D. Haisel ◽  
I. Tichá
Keyword(s):  
Chlorophyll A Fluorescence ◽  
Xanthophyll Cycle ◽  
Chilling Stress ◽  
Photosynthetic Apparatus ◽  
Photosynthetic Performance ◽  
Photochemical Quenching ◽  
Maize Genotypes ◽  
Fluorescence Characteristics ◽  
Non Photochemical Quenching ◽  
And Control

The effect of chilling on light dependence of photosynthetic and chlorophyll a fluorescence characteristics in two maize genotypes CE 704 and CE 810 grown in a glasshouse during spring and autumn was studied. In spring, the net photosynthetic rate (P<sub>N</sub>) of CE 704 plants was not affected by chilling under moderate irradiance but it was strongly affected under a saturating one. This indicates that efficiency of photosynthetic apparatus was not affected by chilling but its capacity was decreased. Contrary to CE 704, CE 810 plants were not affected by chilling under saturating irradiance. In autumn, CE 704 plants adapted to chilling and no statistically significant differencies in P<sub>N</sub> and Fv/Fm between chilled and control plants in the whole range of irradiance were found. Enhanced activity of non-photochemical quenching (NPQ) in chilled CE 704 plants under saturating irradiance corresponded with an increased level of xanthophyll cycle pigments and an increased deepoxidation state of these pigments.

scholarly journals Physiological and productive traits of soybean with metsulfuron-methyl application at early desiccation

2021 ◽  
Vol 56 ◽  
Author(s):  
Jessica Dias Gomes da Silva ◽  
Leandro Galon ◽  
Renan Pawelkiewicz ◽  
Milena Barretta Franceschetti ◽  
Juliane Cervi Portes ◽  
...  
Keyword(s):  
Defense Mechanism ◽  
Electron Transport Rate ◽  
Application Rate ◽  
Photochemical Quenching ◽  
Negative Effects ◽  
Metsulfuron Methyl ◽  
Soybean Plants ◽  
Productive Traits ◽  
Non Photochemical Quenching ◽  
Sowing Period

Abstract The objective of this work was to evaluate the effects of metsulfuron-methyl rates, applied at different times, on the physiological and productive traits of soybean (Glycine max) in two crop years, in field conditions, using cucumber (Cucumis sativus) as a bioindicator plant, in greenhouse conditions. The experiments were conducted in a randomized complete block, in a 4x5 factorial arrangement, with four replicates. Factor A was the herbicide application time (45, 30, 15, and 0 days before soybean sowing, DBS), and factor B was the metsulfuron-methyl rate (0, 3.6, 5.4, 7.2, and 9.0 g ha-1 a.i.). The following variables were evaluated: phytotoxicity, gas exchange, chlorophyll a fluorescence, and yield components. The highest phytotoxicity in soybean plants is observed after the use of the highest rate of metsulfuron-methyl and with sowing at 0 DBS. The electron transport rate drastically reduces with an increasing metsulfuron-methyl rate and sowing proximity, whereas non-photochemical quenching, acting as a defense mechanism, increases in soybean plants exposed to a herbicide carryover of up to 5.4 g ha-1. Metsulfuron-methyl carryover reduces soybean 1,000-grain weight and productivity as a function of application rate and sowing period. For the cucumber plants, negative effects on physiological traits were also verified. An interval of more than 45 days is recommended for sowing soybean after metsulfuron-methyl application for desiccation.

scholarly journals Evaluation of Agronomic Performance of Maize (Zea mays L.) under a Fertilization Gradient in Transylvanian Plain

Agriculture ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 896
Author(s):  
Gabriel Barșon ◽  
Laura Șopterean ◽  
Loredana Alexandra Suciu ◽  
Ioana Crișan ◽  
Marcel Matei Duda
Keyword(s):  
Best Practices ◽  
Agronomic Performance ◽  
Maize Crop ◽  
Maize Hybrids ◽  
Maize Genotypes ◽  
Productivity Potential ◽  
Fertilizer Regimes ◽  
Insight Into ◽  
Shed Light ◽  
Crop Health

In the last few years, Romania has become a top maize producer. Export potential is sustained by ensuring high-quantity and -quality maize. Success of maize crop is highly dependent on inputs. In this context, insight into the potential of different fertilizers to maximize crop performance could shed light on best practices to enhance yields and other traits of interest. The aim of this study was to assess the agronomic performance of maize under a fertilization gradient. Six fertilizer regimes were tested on three maize hybrids between 2018 and 2020, in conditions from the Transylvanian Plain. Results showed that fertilization had a significant influence on yield, thousand kernels weight, grain quality (starch and protein content) and crop health. The experimental year also played a significant role in the expression of productivity potential of maize genotypes. Different fertilizer regimes could be used for targeting desired outcomes, but top performance across all or multiple agronomic components remains a challenge and should receive further attention for optimization.

Light Absorption and Partitioning in Response to Nitrogen in Apple Leaves

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 541a-541
Author(s):  
Lailiang Cheng ◽  
Leslie H. Fuchigami ◽  
Patrick J. Breen
Keyword(s):  
High Light ◽  
Thermal Dissipation ◽  
Photochemical Quenching ◽  
Light Conditions ◽  
Psii Efficiency ◽  
Fluorescence Measurements ◽  
Free Radical Formation ◽  
Highly Correlated ◽  
Non Photochemical Quenching ◽  
Leaf N

Bench-grafted Fuji/M26 apple trees were fertigated with different concentrations of nitrogen by using a modified Hoagland solution for 6 weeks, resulting in a range of leaf N from 1.0 to 4.3 g·m–2. Over this range, leaf absorptance increased curvilinearly from 75% to 92.5%. Under high light conditions (1500 (mol·m–2·s–1), the amount of absorbed light in excess of that required to saturate CO2 assimilation decreased with increasing leaf N. Chlorophyll fluorescence measurements revealed that the maximum photosystem II (PSII) efficiency of dark-adapted leaves was relatively constant over the leaf N range except for a slight drop at the lower end. As leaf N increased, non-photochemical quenching under high light declined and there was a corresponding increase in the efficiency with which the absorbed photons were delivered to open PSII centers. Photochemical quenching coefficient decreased significantly at the lower end of the leaf N range. Actual PSII efficiency increased curvilinearly with increasing leaf N, and was highly correlated with light-saturated CO2 assimilation. The fraction of absorbed light potentially used for free radical formation was estimated to be about 10% regardless of the leaf N status. It was concluded that increased thermal dissipation protected leaves from photo-oxidation as leaf N declined.

scholarly journals Gradual Response of Cyanobacterial Thylakoids to Acute High-Light Stress—Importance of Carotenoid Accumulation

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1916
Author(s):  
Myriam Canonico ◽  
Grzegorz Konert ◽  
Aurélie Crepin ◽  
Barbora Šedivá ◽  
Radek Kaňa
Keyword(s):  
Single Cell ◽  
Thylakoid Membrane ◽  
Intermediate Phase ◽  
Light Stress ◽  
Fast Response ◽  
High Light ◽  
Photochemical Quenching ◽  
Second Phase ◽  
Ros Scavenging ◽  
Non Photochemical Quenching

Light plays an essential role in photosynthesis; however, its excess can cause damage to cellular components. Photosynthetic organisms thus developed a set of photoprotective mechanisms (e.g., non-photochemical quenching, photoinhibition) that can be studied by a classic biochemical and biophysical methods in cell suspension. Here, we combined these bulk methods with single-cell identification of microdomains in thylakoid membrane during high-light (HL) stress. We used Synechocystis sp. PCC 6803 cells with YFP tagged photosystem I. The single-cell data pointed to a three-phase response of cells to acute HL stress. We defined: (1) fast response phase (0–30 min), (2) intermediate phase (30–120 min), and (3) slow acclimation phase (120–360 min). During the first phase, cyanobacterial cells activated photoprotective mechanisms such as photoinhibition and non-photochemical quenching. Later on (during the second phase), we temporarily observed functional decoupling of phycobilisomes and sustained monomerization of photosystem II dimer. Simultaneously, cells also initiated accumulation of carotenoids, especially ɣ–carotene, the main precursor of all carotenoids. In the last phase, in addition to ɣ-carotene, we also observed accumulation of myxoxanthophyll and more even spatial distribution of photosystems and phycobilisomes between microdomains. We suggest that the overall carotenoid increase during HL stress could be involved either in the direct photoprotection (e.g., in ROS scavenging) and/or could play an additional role in maintaining optimal distribution of photosystems in thylakoid membrane to attain efficient photoprotection.

scholarly journals The Role of Acidic Residues in the C Terminal Tail of the LHCSR3 Protein of Chlamydomonas reinhardtii in Non-Photochemical Quenching

2021 ◽  
pp. 6895-6900
Author(s):  
Franco V. A. Camargo ◽  
Federico Perozeni ◽  
Gabriel de la Cruz Valbuena ◽  
Luca Zuliani ◽  
Samim Sardar ◽  
...  
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Photochemical Quenching ◽  
Acidic Residues ◽  
Non Photochemical Quenching

scholarly journals Effects of iron limitation on carbon balance and photophysiology of the Antarctic diatom Chaetoceros cf. simplex

Polar Biology ◽  
2021 ◽  
Author(s):  
Deborah Bozzato ◽  
Torsten Jakob ◽  
Christian Wilhelm ◽  
Scarlett Trimborn
Keyword(s):  
Oxygen Evolution ◽  
Photochemical Quenching ◽  
Gross Photosynthesis ◽  
Manganese Zinc ◽  
C Cycle ◽  
Uptake Rates ◽  
Carbon Pump ◽  
Non Photochemical Quenching ◽  
The Antarctic ◽  
Biological Carbon Pump

AbstractIn the Southern Ocean (SO), iron (Fe) limitation strongly inhibits phytoplankton growth and generally decreases their primary productivity. Diatoms are a key component in the carbon (C) cycle, by taking up large amounts of anthropogenic CO2 through the biological carbon pump. In this study, we investigated the effects of Fe availability (no Fe and 4 nM FeCl3 addition) on the physiology of Chaetoceros cf. simplex, an ecologically relevant SO diatom. Our results are the first combining oxygen evolution and uptake rates with particulate organic carbon (POC) build up, pigments, photophysiological parameters and intracellular trace metal (TM) quotas in an Fe-deficient Antarctic diatom. Decreases in both oxygen evolution (through photosynthesis, P) and uptake (respiration, R) coincided with a lowered growth rate of Fe-deficient cells. In addition, cells displayed reduced electron transport rates (ETR) and chlorophyll a (Chla) content, resulting in reduced cellular POC formation. Interestingly, no differences were observed in non-photochemical quenching (NPQ) or in the ratio of gross photosynthesis to respiration (GP:R). Furthermore, TM quotas were measured, which represent an important and rarely quantified parameter in previous studies. Cellular quotas of manganese, zinc, cobalt and copper remained unchanged while Fe quotas of Fe-deficient cells were reduced by 60% compared with High Fe cells. Based on our data, Fe-deficient Chaetoceros cf. simplex cells were able to efficiently acclimate to low Fe conditions, reducing their intracellular Fe concentrations, the number of functional reaction centers of photosystem II (RCII) and photosynthetic rates, thus avoiding light absorption rather than dissipating the energy through NPQ. Our results demonstrate how Chaetoceros cf. simplex can adapt their physiology to lowered assimilatory metabolism by decreasing respiratory losses.

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