Physiological changes and UV protection in the aquatic liverwort Jungermannia exsertifolia subsp. cordifolia along an altitudinal gradient of UV-B radiation

Here we report the effects of a natural altitudinal gradient of UV-B radiation, from 1140 to 1816 m altitude, on the physiology of the aquatic liverwort Jungermannia exsertifolia Steph. subsp. cordifolia (Dumort.) Váña collected in mountain streams. Photosynthetic pigments, net photosynthesis and dark respiration rates, chlorophyll fluorescence, protein concentration, sclerophylly, and UV-absorbing compounds [both global UV absorbance of methanol-extractable UV-absorbing compounds (MEUVAC) and concentrations of five individual compounds] were measured. Two new caffeic acid derivatives were discovered: 5″-(7″,8″-dihydroxycoumaroyl)-2-caffeoylmalic acid and 5″-(7″,8″-dihydroxy-7-O-β-glucosyl-coumaroyl)-2-caffeoylmalic acid, whereas three additional compounds were already known in other species: p-coumaroylmalic acid, phaselic acid (both compounds in their cis- and trans- forms) and feruloylmalic acid. Most physiological variables changed considerably along the altitudinal gradient, but only six showed significant linear relationships with altitude: MEUVAC levels, the concentrations of the two new secondary compounds, the maximal apparent electron transport rate through PSII (ETRmax) and the maximal non-photochemical quenching (NPQmax) increased with altitude, whereas photoinhibition percentage decreased. A principal components analysis (PCA) was conducted to rank the values of the physiological and ecological variables obtained along the altitudinal transect, showing that those variables correlated with altitude were responsible for the ordination of the sampling points. The liverwort was not adversely affected by the changing conditions along the altitudinal gradient and, in particular, by the increasing UV-B irradiance, probably because the characteristics shown by high-altitude populations may confer tolerance to high UV-B levels. The response to UV-B of the two new compounds suggests that they could be used as indicators of the spatial changes in UV-B radiation.

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Photosynthesis sensitivity to NH4+-N change with nitrogen fertilizer type

Plant Soil and Environment ◽

10.17221/7418-pse ◽

2014 ◽

Vol 60 (No. 6) ◽

pp. 274-279 ◽

Cited By ~ 6

Author(s):

A. Nasraoui-Hajaji ◽

H. Gouia

Keyword(s):

Net Photosynthesis ◽

Dry Weight ◽

N Fertilization ◽

Photochemical Quenching ◽

Negative Effects ◽

Ps Ii ◽

Chl A ◽

Inhibitory Site ◽

Tomato Growth ◽

Non Photochemical Quenching

N-fertilization type affected differently tomato growth. In the field experiment, hydroponic cultures were conducted using NO3-N (5 mmol); mixture of KNO3-N (3 mmol) and (NH4)2SO4-N (2 mmol); NH4+-N (5 mmol) or urea (5 mmol) as nitrogen source. Compared to nitrate, ammonium and urea had negative effects on morphology and dry matter production. Effects of the different nitrogen forms were investigated by measuring several photosynthesis parameters and chl a fluorescence. Two different significant types of reaction were found. When nitrogen was added as ammonium or urea, dry weight, chlorophyll tenor, transpiration rate, stomatal conductance and photosynthetic activity were inhibited. Supply of ammonium or urea, reduced the ratio (Fv/Fm), photochemical quenching and enhanced the non photochemical quenching. These data suggest that the adverse decrease in tomato growth under ammonium or urea supply may be related principally to inhibition of net photosynthesis activity. The high non photochemical quenching shown in tomato fed with ammonium or urea indicated that PS II was the inhibitory site of NH4+-N which was directly uptaken by roots, or librated via urea hydrolysis cycle.

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Effects of nutrient amendment and environment on growth and gas exchange for introduced Penniseturn setaceum in Hawaii

Canadian Journal of Botany ◽

10.1139/b96-032 ◽

1996 ◽

Vol 74 (2) ◽

pp. 268-275 ◽

Cited By ~ 5

Author(s):

David G. Williams ◽

R. Alan Black

Keyword(s):

Water Potential ◽

Altitudinal Gradient ◽

Dark Respiration ◽

Nitrogen Concentration ◽

Resource Limitation ◽

Net Photosynthesis ◽

Leaf Nitrogen ◽

Carbon Uptake ◽

Lower Altitude ◽

Nutrient Amendment

We examined the effects of a balanced soil nutrient amendment on photosynthesis, growth, and reproduction for the alien grass Penniseturn setaceum across an altitudinal gradient on the island of Hawaii. Nutrient amendment of plants enhanced aboveground growth, height, and numbers of reproductive tillers and inflorescences similarly across the altitudinal gradient. Nutrient amendment increased aboveground biomass 22 to 25% but had little effect on predawn water potential, leaf nitrogen concentration, or photosynthesis. Leaf nitrogen concentrations declined with altitude (22 ± 0.5 mg/g N at the coastal site; 16 ± 0.1 mg/g N at the subalpine site) and partially compensated for decreases in specific leaf area with altitude. Plants at the subalpine site had high dark respiration rates, low CO2 saturated photosynthetic rates, and low photosynthetic nitrogen use efficiencies compared with plants at lower altitudes. Chilling temperatures or high respiratory rates may limit net carbon uptake and growth for plants at higher altitude relative to plants at lower altitude. Seasonal patterns of net photosynthesis, stomatal conductance, and water potential suggest that drought colimited carbon uptake and growth at the low altitude site. Success of Penniseturn in Hawaii may stem, in part, from its ability to respond morphologically to compensate for heterogeneous nutrient and water availability across different habitats. Keywords: altitude, Hawaii, nutrient amendment, photosynthesis, Penniseturn setaceum, resource limitation.

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Intoxication and Physiological Aspects of Forage Plants and Weeds Submitted to Clomazone Atmospheric Waste

Planta Daninha ◽

10.1590/s0100-83582018360100006 ◽

2018 ◽

Vol 36 (0) ◽

Author(s):

M.M. SILVA ◽

J.B. SANTOS ◽

E.A. SANTOS ◽

M.V. SANTOS ◽

L.T. SARDINHA ◽

...

Keyword(s):

Quantum Yield ◽

Plant Species ◽

Photochemical Quenching ◽

Maximum Quantum Yield ◽

Physiological Variables ◽

Fluorescence Maximum ◽

Fodder Plants ◽

Urochloa Brizantha ◽

Non Photochemical Quenching ◽

Quantum Yield Of Psii

ABSTRACT: Herbicide volatilization may generate environmental and agricultural problems and result in visual or physiological contamination of non-target plant species. Thus, the goal of this research was to study the fluorescence of chlorophyll a in weeds and fodder plants under the effect of clomazone in the form of atmospheric waste. The experiment was conducted under field conditions designed in randomized blocks with four replications, in a 6 x 4 factor scheme, with six plant species: Dolichos lablab, bicolor Sorgum, Urochloa brizantha, Macrotyloma axillare, Portulaca oleracea and Sida rhombifolia. There were four solutions containing 0, 360, 720 and 1,080 g ha-1 of clomazone (0, 0.05, 0.10 and 0.15 mg L-1, considered as the volume). Seedbeds were built and covered with transparent polyethylene film of 150 μm, with a volume of 12 m³. Fodder plants were sown in line, while weeds were selected according to the incidence. On the sixteenth day after emergence, concentrations of herbicide diluted on three petri dishes were inserted. After 72 hours of exposure, the tunnels were opened and the dishes were removed, noticing evaporation of the product. The following evaluationswere performed: plant poisoning, initial fluorescence, maximum quantum yield of PSII, photochemical quenching, non-photochemical quenching and chlorophyll content. Even at concentrations that do not promote visual effect, clomazone can cause significant damage in the photosynthetic activity of the species. The physiological variables chlorophyll, maximum quantum yield of PSII and initial chlorophyll fluorescence can be effectively used to monitor clomazone waste in the atmosphere.

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Physiological characterization of grapevine rootstocks grown in soil with increasing zinc doses

Revista Brasileira de Engenharia Agrícola e Ambiental ◽

10.1590/1807-1929/agriambi.v19n10p973-980 ◽

2015 ◽

Vol 19 (10) ◽

pp. 973-980 ◽

Cited By ~ 1

Author(s):

Jovani Zalamena ◽

George W. Melo ◽

Henrique P. Santos ◽

Leandro S. da Silva ◽

Flavio B. Fialho ◽

...

Keyword(s):

Quantum Yield ◽

Photosystem Ii ◽

Fluorescence Analysis ◽

Photochemical Quenching ◽

Effective Quantum Yield ◽

Physiological Characterization ◽

Physiological Variables ◽

Negative Effect ◽

Soil Zn ◽

Non Photochemical Quenching

ABSTRACTThis study aimed to evaluate the performance of grapevine rootstocks under increasing levels of Zn in the soil and to identify physiological variables that can be used as indicators of excess of Zn in the soil. The rootstocks SO4, Paulsen1103, IAC572, IAC313 and 420A were grown in pots containing soil, which received Zn doses of 0, 20, 40, 80 or 160 mg kg-1 of soil. Dry matter (DM), Zn content in shoots and roots, chlorophyll index, initial fluorescence (Fo), maximum fluorescence (Fm), maximum quantum yield of photosystem II (Fv/Fm), effective quantum yield of photosystem II (Y-II) and non-photochemical quenching (NPQ) were evaluated. The increase of Zn levels in the soil decreased DM in all rootstocks, and IAC572 was superior to the others. The variation in the indices of chlorophyll a and b had little expression in relation the soil Zn levels, but allowed identifying that the rootstocks Paulsen 1103, 420A and SO4 are sensitive to Zn toxicity and that IAC572 and IAC313 were not sensitive to the tested levels. Fluorescence analysis showed a negative effect of Zn contents on the variables Fo, Fm, Y-II and NPQ in all rootstocks, which proved to be good indicators of Zn phytotoxicity.

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Photosynthetic Physiology Comparisons between No Tillage and Sod Culture of Citrus Farming in Different Seasons under Various Light Intensities

Agronomy ◽

10.3390/agronomy11091805 ◽

2021 ◽

Vol 11 (9) ◽

pp. 1805

Author(s):

Chung-I. Chen ◽

Kuan-Hung Lin ◽

Meng-Yuan Huang ◽

Chih-Kai Yang ◽

Yu-Hsiu Lin ◽

...

Keyword(s):

Dark Respiration ◽

Photosynthetic Apparatus ◽

Net Photosynthesis ◽

Photochemical Quenching ◽

Photosynthetic Parameters ◽

Light Quantum ◽

No Tillage ◽

Photosynthetic Physiology ◽

Light Intensities ◽

Different Seasons

Sod culture (SC) and no tillage (NT) are modern orchard management systems, and are two different bases for the sustainable development and production of citrus orchards in Taiwan. However, there is no information about the efficiency of either NT or SC on the photosynthetic physiology of farmed citrus under different seasons and varying light intensities. The objective of this study was to clarify the impacts of SC and NT under eco-friendly farming management on the photosynthetic apparatus of an important plantation citrus species in response to varying light intensities over the seasons. The results showed that Rd (dark respiration rate of CO2), Qy (light quantum yield of CO2), LCP (light compensation point), Amax (maximum net assimilation of CO2), and Fv/Fm values of citrus plants under SC were somewhat higher under NT in the same season, particularly in the fall and in winter. As light intensity increased from 200 to 2000 μmol photon m−2 s−1 PPFD, higher Pn (net photosynthesis rate), Gs (stomatal conductance), ETR (electron transport rate), NPQ (non-photochemical quenching), and Fv/Fm (potential quantum efficiency of PSII) values were observed in spring and summer compared to the fall and winter, and increasing NPQ and decreasing Fv/Fm values were observed in all seasons. Positive and significant correlations were shown between the Pn and Gs under NT and SC in all seasons with all light illuminations, whereas significant and negative relationships were observed between the ETR and NPQ under NT in fall and winter at 1200~2000 PPFD. In short, ETR was useful for non-destructive estimations of Pn and NPQ since these indices were significantly and positively correlated with ETR in citrus leaves exposed to 0~1200 PPFD in all seasons and 1200~2000 PPFD in spring, the fall, and winter, providing a quick means to identify the physiological condition of plants under various seasons and tillages. The precise management of photosynthetic parameters such as ETR in response to light irradiances under varied seasons also provides implications for sustainable citrus production for tillage cropping systems in future higher CO2 and potentially wetter or drier environments. The tillages may hold promise for maximizing the economic efficiency of the growth and development of citrus plants grown in the field.

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UNRAVELING PHYSIOLOGICAL TRAITS OF Jatropha curcas, A BIODIESEL PLANT, TO OVERCOME SALINITY CONDITIONS

Revista Caatinga ◽

10.1590/1983-21252020v33n217rc ◽

2020 ◽

Vol 33 (2) ◽

pp. 446-457

Author(s):

YURI LIMA MELO ◽

ROSA RODÉS GARCIA ◽

CRISTIANE ELIZABETH COSTA DE MACÊDO ◽

EDUARDO ALFONSO ORTEGA DELGADO ◽

JOSEMIR MOURA MAIA ◽

...

Keyword(s):

Jatropha Curcas ◽

Leaf Growth ◽

Gene Expression Pattern ◽

Net Photosynthesis ◽

Photochemical Quenching ◽

Dry Land ◽

Land Systems ◽

Half Strength ◽

Non Photochemical Quenching ◽

Global Population

ABSTRACT Dry land systems spread all over the world and comprise 41.3% of the terrestrial area, which host 34.7% of the global population, so it is convenient to propose crops able to grow there. Jatropha curcas is a plant adapted to arid and semiarid regions as well as sub-humid conditions, being a potential source of biodiesel. The challenge is to understand the physiology of J. curcas, which enables it to live under saline and drought conditions. The seeds of J. curcas used came from Ciego de Ávila Province, Cuba. Seven-day-old seedlings were cultivated in 1.5 L pots with half strength Hoagland solution for 42 days under semi-controlled conditions. NaCl added to solutions in pots provided 75 or 150 mM treatments for 240 h before measurements. Leaf growth, net photosynthesis and stomatal pore area were affected by 150 mM NaCl. Non-photochemical quenching of leaves was only changed by 150 mM NaCl after 24 h; the electron transport rate had a tendency to decrease in leaves under saline conditions. The gene expression pattern changed for SOS1 and HKT1 according to the NaCl used in the medium, indicating active mechanism to deal with Na+ in the cell. In general, Cuban J. curcas plants were able to grow and perform photosynthesis under 75 mM NaCl, which represents 7 dS m-1, a condition that restricts growth for many plant species.

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Photosynthetic characteristics of a tropical population of Nitella cernua (Characeae, Chlorophyta)

Brazilian Journal of Plant Physiology ◽

10.1590/s1677-04202006000300004 ◽

2006 ◽

Vol 18 (3) ◽

pp. 379-388 ◽

Cited By ~ 2

Author(s):

Jair Vieira Jr. ◽

Orlando Necchi Jr.

Keyword(s):

Dark Respiration ◽

Net Photosynthesis ◽

Wide Distribution ◽

Photosynthetic Performance ◽

High Irradiance ◽

Photosynthetic Characteristics ◽

Southeastern Brazil ◽

Photochemical Quenching ◽

O2 Evolution ◽

Photosynthetic Rates

Photosynthetic characteristics (assessed by chlorophyll fluorescence and O2 evolution) were analysed monthly during one year in a tropical population of Nitella cernua from southeastern Brazil (20º50'32" S, 49º26'15" W). Parameters derived from photosynthesis-irradiance (PI) curves by fluorescence (high values of the photosynthetic parameter, Ik, and lack or low values of photoinhibition, beta) suggested adaptation to high irradiance, whereas those by O2 evolution showed a different pattern (low values of Ik and compensation irradiance, Ic, high values of photosynthetic efficiency, alpha, and photoinhibition). Parameters from PI curves by O2 evolution suggested light acclimation: Ik and maximum photosynthetic rate, Pmax (as rETR, relative electron transfer rate) increased, whereas a became significantly lower under higher irradiance (winter). This pattern is an adjustment of both number and size of photosynthetic units. Photosynthetic performance assessed by fluorescence revealed two seasonal periods: higher values of Pmax (rETR), Ik and non-photochemical quenching from October to March (rainy season), and lower values from April to October (dry season). Temperature responses were observed only in summer, but temperature optima were different between methods: peaks of net photosynthesis occurred at 20ºC, whereas rETR increased towards higher temperatures (up to 30ºC). Dark respiration increased with higher temperatures. Current velocity had a stimulatory effect on photosynthetic rates, as suggested by positive correlations with Pmax (rETR) and alpha. pH experiments revealed highest net photosynthetic rates under pH 4.0, suggesting higher affinity for CO2 than HCO3-. This broad range of responses of photosynthetic characteristics of this N. cernua population to irradiance, temperature, and pH/inorganic carbon reflects a wide tolerance to variations in these environmental variables, which probably contribute to the wide distribution of this species.

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Light Absorption and Partitioning in Response to Nitrogen in Apple Leaves

HortScience ◽

10.21273/hortsci.33.3.541a ◽

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.

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

Cells ◽

10.3390/cells10081916 ◽

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.

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