scholarly journals Effects of Smoke-water on Photosynthetic Characteristics of Isatis indigotica Seedlings

2012 ◽  
Vol 2 (2) ◽  
pp. 24 ◽  
Author(s):  
Jie Zhou ◽  
Lei Fang ◽  
Xiao Wang ◽  
Lanping Guo ◽  
Luqi Huang
Keyword(s):  
Water Treatment ◽  
Stomatal Conductance ◽  
Plant Growth ◽  
Photochemical Efficiency ◽  
Photosynthetic Characteristics ◽  
Photochemical Quenching ◽  
Isatis Indigotica ◽  
Photochemical Efficiency Of Psii ◽  
Non Photochemical Quenching ◽  
Smoke Water

<p>Smoke-water (SW) had been reported to improve the growth of <em>Isatis indigotica</em>, a Chinese medicinal plant. However, there were very few reports on the mechanism of smoke-water improving plant growth. In this study the effects of smoke-water on the photosynthetic characteristics of <em>I.</em><em> indigotica</em> seedlings were investigated for the purpose of understanding the mechanism behind this improved plant growth. The results showed that net photosynthetic rate (<em>P<sub>n</sub></em>) was increased by smoke-water, reaching a maximum on 15, 5 and 15 d after treatment with smoke-water at dilutions of 1:500, 1:1000 and 1:2000 respectively. Transpiration rate (<em>T<sub>r</sub></em>) and stomatal conductance (<em>G<sub>s</sub></em>) both showed similar trends to<sub> </sub><em>P<sub>n</sub></em>, however, intercellular CO<sub>2</sub> concentration<em> </em>(<em>C<sub>i</sub></em>) was decreased with smoke-water treatment. The F<sub>v</sub>/F<sub>m</sub> was not significantly influenced by smoke-water treatment. The ?PSII was markedly promoted with the application of smoke-water (1:1000) compared with the control and the coefficient of photochemical quenching (qP) showed a similar trend to ?PSII. However the coefficient of non-photochemical quenching of chlorophyll (NPQ) was decreased with treatment of smoke-water. These findings indicate that smoke-water treatment induce an increase in photosynthesis and suggest the main factors leading to this might be the improved stomatal conductance and the enhanced level of the photochemical efficiency of PSII in leaves.</p>

Plant growth-promoting bacteria as a tool to improve salinity tolerance in sweet pepper

2012 ◽  
Vol 39 (1) ◽  
pp. 82 ◽  
Author(s):  
Francisco M. del Amor ◽  
Paula Cuadra-Crespo
Keyword(s):  
Stomatal Conductance ◽  
Plant Growth ◽  
Leaf Gas Exchange ◽  
Photochemical Efficiency ◽  
Sweet Pepper ◽  
Saline Stress ◽  
Plant Growth Promoting Bacteria ◽  
Bacterial Inoculants ◽  
Photochemical Efficiency Of Psii ◽  
Plant Growth Promoting

To characterise the effect of bacterial inoculants (Azospirillum brasilense and Pantoea dispersa) on the response of sweet pepper (Capsicum annuum L.) to saline stress, plants were exposed to 0, 40, 80 and 120 mM NaCl in solution. The effect on plant growth; leaf gas exchange; NO3–, Cl–, K+ and Na+ accumulation; and chlorophyll fluorescence and content were investigated. Total plant DW was reduced significantly by salinity but when inoculants were applied, DW was increased. Inoculated plants showed higher DW accumulation in the roots. Salinity levels up to 80 mM NaCl did not affect the net assimilation rate in inoculated plants but 40 mM NaCl was enough to reduce this parameter in non-inoculated plants. The leaf area ratio was not modified substantially by inoculation. The leaf Cl– concentration of inoculated plants was reduced at the highest salinity, compared with control plants, and NO3– concentration increased markedly. A higher K+ : Na+ ratio was found in inoculated plants. Leaf photosynthesis and stomatal conductance were impaired significantly at moderate, but not low, salinity, the effect of inoculation being enough to maintain higher stomatal conductance under higher stress. The photochemical efficiency of PSII and the relative chlorophyll content were not affected by the inoculants. Thus, the effects of the inoculants on the response to salinity were due mainly to stomatal regulation of photosynthesis rather than effects on biochemical limitations on photosynthesis. These results indicate the benefits of these bacterial inoculants in ameliorating the deleterious effect of NaCl in a salt-sensitive crop like sweet pepper.

scholarly journals Exogenous putrescine alleviates photoinhibition caused by salt stress through increasing cyclic electron flow in cucumber

2018 ◽  
Author(s):  
Xinyi Wu ◽  
Sheng Shu ◽  
Yu Wang ◽  
Ruonan Yuan ◽  
Shirong Guo
Keyword(s):  
Salt Stress ◽  
Electron Flow ◽  
Critical Role ◽  
Photochemical Efficiency ◽  
Cyclic Electron Flow ◽  
Photochemical Quenching ◽  
Photochemical Efficiency Of Psii ◽  
High Level ◽  
Non Photochemical Quenching ◽  
Related Proteins

AbstractWhen plants suffer from abiotic stresses, cyclic electron flow (CEF) is induced for photoprotection. Putrescine (Put), a main polyamine in chloroplasts, plays a critical role in stress tolerance. To elucidate the mechanism of Put regulating CEF for salt-tolerance in cucumber leaves, we measured chlorophyll fluorescence, P700 redox state, ATP and NADPH accumulation and so on. The maximum photochemical efficiency of PSII (Fv/Fm) was not influenced by NaCl and/or Put, but the activity of PSI reaction center (P700) was seriously inhibited by NaCl. Salt stress induced high level of CEF, moreover, NaCl and Put treated plants exhibited much higher CEF activity and ATP accumulation than single salt-treated plants to provide adequate ATP/NADPH ratio for plants growth. Furthermore, Put decreased the trans-membrane proton gradient (ΔpH), accompanied by reducing the pH-dependent non-photochemical quenching (qE) and increasing efficient quantum yield of PSII (Y(II)). The ratio of NADP+/NADPH in salt stressed leaves was significantly increased by Put, indicating that Put relieved over-reduction pressure at PSI accepter side. Taken together, our results suggest that exogenous Put enhances CEF to supply extra ATP for PSI recovery and CO2 assimilation, decreases ΔpH for electron transport related proteins staying active, and enable the non-photochemical quenching transformed into photochemical quenching.

The operation of the lutein epoxide cycle correlates with energy dissipation

2003 ◽  
Vol 30 (3) ◽  
pp. 319 ◽  
Author(s):  
José I. García-Plazaola ◽  
Antonio Hernández ◽  
José M. Olano ◽  
José M. Becerril
Keyword(s):  
Energy Dissipation ◽  
Partial Correlation ◽  
Photochemical Efficiency ◽  
Parasitic Plants ◽  
Photochemical Quenching ◽  
Photochemical Efficiency Of Psii ◽  
Statistical Approaches ◽  
Non Photochemical Quenching ◽  
Shade Leaves

A new xanthophyll cycle involving de-epoxidation of lutein epoxide (Lx) into lutein in the light and epoxidation back in the dark has been recently described in parasitic plants and in trees from the genus Quercus. To explore the role of the Lx cycle in photoprotection, shade leaves of red oak (Q. rubra), with a relatively high Lx pool, were exposed to different light intensities. Both violaxanthin and Lx were de-epoxidised to the same extent, although the initial kinetics differed, with a rate proportional to the light intensity. De-epoxidation of violaxanthin and Lx was inhibited by dithiothreitol, suggesting that the same enzyme, violaxanthin de-epoxidase (VDE), catalyses both reactions. Dark recovery lagged in the case of Lx, and after 5 h in darkness, the Lx cycle was much more de-epoxidised than the violaxanthin cycle. The different rates of epoxidation of the violaxanthin and Lx cycles were used to study the role of the Lx cycle in photoprotection. Statistical approaches (partial correlation and multiple regression) indicate that in these leaves, maximal photochemical efficiency of PSII (Fv/Fm) and non-photochemical quenching are correlated with the level of Lx de-epoxidation. The potential implications of this finding for the understanding of the photosynthetic process in shaded and understorey leaves are discussed.

scholarly journals Effects of Different Shading Rates on the Photosynthesis and Corm Weight of Konjac Plant

2019 ◽  
Vol 47 (3) ◽  
Author(s):  
Yaoguo QIN ◽  
Zesheng YAN ◽  
Honghui GU ◽  
Zhengxiang WANG ◽  
Xiong JIANG ◽  
...  
Keyword(s):  
Photosynthetic Efficiency ◽  
Daily Variation ◽  
Photochemical Efficiency ◽  
High Yield ◽  
Photochemical Quenching ◽  
Digital Object Identifier ◽  
Chlorophyll Fluorescence Parameters ◽  
Relative Electron ◽  
Comprehensive Comparison ◽  
Non Photochemical Quenching

To study the effects of shading level on the photosynthesis and corm weight of konjac plant, the chlorophyll fluorescence parameters, daily variation of relative electron transport rate (rETR), net photosynthetic rate (Pn), and corm weight of konjac plants under different treatments were measured and comparatively analyzed through covered cultivation of biennial seed corms with shade nets at different shading rates (0%, 50%, 70%, and 90%). The results showed that with the increase in shading rate, the maximum photochemical efficiency, potential activity, and non-photochemical quenching of photosystem Ⅱ (PSⅡ) of konjac leaves constantly increased, whereas the actual photosynthetic efficiency, rETR, and photochemical quenching of PSⅡ initially increased and then decreased. This result indicated that moderate shading could enhance the photosynthetic efficiency of konjac leaves. The daily variation of rETR in konjac plants under unshaded treatment showed a bimodal curve, whereas that under shaded treatment displayed a unimodal curve. The rETR of plants with 50% treatment and 70% treatment was gradually higher than that under unshaded treatment around noon. The moderate shading could increase the Pn of konjac leaves. The stomatal conductance and transpiration rate of the leaves under shaded treatment were significantly higher than those of the leaves under unshaded treatment. Shading could promote the growth of plants and increase corm weight. The comprehensive comparison shows that the konjac plants had strong photosynthetic capacity and high yield when the shading rate was 50%-70% for the area.   ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********

Low induction of non-photochemical quenching and high photochemical efficiency in the annual desert plantAnastatica hierochuntica

2014 ◽  
Vol 151 (4) ◽  
pp. 544-558 ◽  
Author(s):  
Amir Eppel ◽  
Ruth Shaked ◽  
Gil Eshel ◽  
Simon Barak ◽  
Shimon Rachmilevitch
Keyword(s):  
Photochemical Efficiency ◽  
Photochemical Quenching ◽  
Non Photochemical Quenching

Promoting pepper (Capsicum annuum) photosynthesis via chloroplast ultrastructure and enzyme activities by optimising the ammonium to nitrate ratio

2020 ◽  
Vol 47 (4) ◽  
pp. 303
Author(s):  
Jing Zhang ◽  
Jianming Xie ◽  
Yantai Gan ◽  
Jeffrey A. Coulter ◽  
Mohammed Mujitaba Dawuda ◽  
...  
Keyword(s):  
Plant Growth ◽  
Capsicum Annuum ◽  
Photosynthetic Rate ◽  
Large Subunit ◽  
Photochemical Efficiency ◽  
Chloroplast Ultrastructure ◽  
Photochemical Quenching ◽  
Gas Exchange Parameters ◽  
Chilli Pepper ◽  
N Assimilation

Optimal plant growth in many species is achieved when the two major forms of N are supplied at a particular ratio. In this pot experiment, the effects of five different ammonium:nitrate ratios (ANRs) (0:100, 12.5:87.5, 25:75, 37.5:62.5, and 50:50) on photosynthesis efficiency in chilli pepper (Capsicum annuum L.) plants were evaluated. The results showed that an ANR of 25:75 increased the contents of chl a, leaf area and dry matter, whereas chl b content was not affected by the ANRs. Regarding chlorophyll fluorescence, an ANR of 25:75 also enhanced the actual photochemical efficiency, photochemical quenching and maximum photosynthetic rate. However, the 0:100 and 50:50 ANRs resulted in higher values for nonphotochemical quenching. An inhibition of maximal photochemical efficiency was found when 50% NH4+ was supplied at the later stage of plant growth. The addition of 25% or 37.5% NH4+ was beneficial for gas exchange parameters and the 25% NH4+ optimised the thylakoid of chloroplasts. Compared with nitrate alone, 12.5–50% NH4+ upregulated glutamate dehydrogenase (GDH), the large subunit and the small subunit of Rubisco. It can be concluded that the 25:75 ANR accelerated N assimilation through active GDH, which provides a material basis for chloroplast and Rubisco formation, resulting in the increased photosynthetic rate and enhanced growth in chilli pepper.

High night temperature decreases leaf photosynthesis and pollen function in grain sorghum

2011 ◽  
Vol 38 (12) ◽  
pp. 993 ◽  
Author(s):  
P. V. Vara Prasad ◽  
Maduraimuthu Djanaguiraman
Keyword(s):  
Climate Models ◽  
Seed Set ◽  
Membrane Damage ◽  
Photochemical Efficiency ◽  
Pollen Grains ◽  
High Temperature Stress ◽  
Photochemical Quenching ◽  
Night Temperature ◽  
Non Photochemical Quenching ◽  
Quantum Yield Of Psii

High temperature stress is an important abiotic stress limiting sorghum (Sorghum bicolor (L.) Moench) yield in arid and semiarid regions. Climate models project greater increases in the magnitude of night temperature compared with day temperature. We hypothesise that high night temperature (HNT) during flowering will cause oxidative damage in leaves and pollen grains, leading to decreased photosynthesis and seed-set, respectively. The objectives of this research were to determine effects of HNT on (1) photochemical efficiency and photosynthesis of leaves, and (2) pollen functions and seed-set. Sorghum plants (hybrid DK-28E) were exposed to optimum night temperature (ONT; 32 : 22°C, day maximum :  night minimum) or HNT (32 : 28°C, day maximum : night minimum) for 10 days after complete panicle emergence. Exposure to HNT increased thylakoid membrane damage and non-photochemical quenching. However, HNT decreased chlorophyll content, quantum yield of PSII, photochemical quenching, electron transport rate and photosynthesis of leaves as compared with ONT. Exposure to HNT increased the reactive oxygen species (ROS) level of leaves and pollen grains. Lipid molecular species analyses in pollen grains showed that HNT decreased phospholipid saturation levels and altered various phospholipid levels compared with ONT. These changes in phospholipids and greater ROS in pollen grains may be responsible for decreased pollen function, leading to lower seed-set.

scholarly journals WATER DEFICIT ENSURES THE PHOTOCHEMICAL EFFICIENCY OF Copaifera langsdorffii Desf1

2017 ◽  
Vol 41 (2) ◽  
Author(s):  
Angélica Lino Rodrigues ◽  
Liane Lima ◽  
Thayssa Rabelo Schley ◽  
Luiz Fernando Rolim de Almeida
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Photochemical Efficiency ◽  
Water Shortage ◽  
Photochemical Activity ◽  
Photochemical Quenching ◽  
High Plasticity ◽  
Effective Quantum Yield ◽  
Water Restriction ◽  
Copaifera Langsdorffii

ABSTRACT The intensity and frequency of drought periods has increased according to climate change predictions. The fast overcome and recovery are important adaptive features for plant species found in regions presenting water shortage periods. Copaifera langsdorffii is a neotropical species that has developed leaves presenting physiological mechanisms and morphological adaptations that allow its survival under seasonal water stress. We aimed in this work to observe substantial physiological responses for water saving and damage representative to the photochemical reaction after exposed plants to water stress and to subsequent recovery. We found in plants mechanisms to control water loss through the lower stomatal conductance, even after rehydration. It goes against the rapid recovery of leaves, indicated by the relative water content values restored to previously unstressed plants. Stomatal conductance was the only variable presenting high plasticity index. In photochemical activity, the species presented higher photochemical quenching, electron transport rate and effective quantum yield of photosystem II when they were subjected to rehydration after water stress period. Our results suggest that C. langsdorffii presented rapid rehydration and higher photochemical efficiency even after water restriction. These data demonstrate that this species can be used as a model for physiological studies due to the adjustment developed in response to different environmental schemes.

scholarly journals Both Multi-Segment Light Intensity and Extended Photoperiod Lighting Strategies, with the Same Daily Light Integral, Promoted Lactuca sativa L. Growth and Photosynthesis

Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 857 ◽  
Author(s):  
Hanping Mao ◽  
Teng Hang ◽  
Xiaodong Zhang ◽  
Na Lu
Keyword(s):  
Quantum Yield ◽  
Light Intensity ◽  
Plant Growth ◽  
Light Stress ◽  
Photochemical Quenching ◽  
Daily Light Integral ◽  
Weak Light ◽  
Research On Application ◽  
Non Photochemical Quenching ◽  
Light Integral

With the rise of plant factories around the world, more and more crops are cultivated under artificial light. Studies on effects of lighting strategies on plant growth, such as different light intensities, photoperiods, and their combinations, have been widely conducted. However, research on application of multi-segment light strategies and associated plant growth mechanisms is still relatively lacking. In the present study, two lighting strategies, multi-segment light intensity and extended photoperiod, were compared with a constant light intensity with a 12 h light/12 h dark cycle and the same daily light integral (DLI). Both lighting strategies promoted plant growth but acted via different mechanisms. The multi-segment light intensity lighting strategy promoted plant growth by decreasing non-photochemical quenching (NPQ) of the excited state of chlorophyll and increasing the quantum yield of PSII electron transport (PhiPSII), quantum yield of the carboxylation rate (PhiCO2), and photochemical quenching (qP), also taking advantage of the circadian rhythm. The extended photoperiod lighting strategy promoted plant growth by compensating for weak light stress and increasing light-use efficiency by increasing chlorophyll content under weak light conditions.

scholarly journals Biochemical and Molecular Effects Induced by Triacontanol in Acquired Tolerance of Rice to Drought Stress

Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1119
Author(s):  
Basmah M. Alharbi ◽  
Awatif Mahfouz Abdulmajeed ◽  
Heba Hassan
Keyword(s):  
Drought Stress ◽  
Stomatal Conductance ◽  
Oryza Sativa L ◽  
Water Status ◽  
Stomatal Closure ◽  
Photochemical Efficiency ◽  
Seed Priming ◽  
Plant Tolerance ◽  
Photochemical Efficiency Of Psii ◽  
Aba Metabolism

To assess the effect of triacontanol (TRIA) on rice plants grown under normal or drought conditions, rice seeds were presoaked in TRIA (35 ppm) for two hours. After 20 days of sowing, rice seedlings developed from TRIA-treated or untreated seeds were subjected to drought stress. After 10 days of plant exposure to drought stress, data of major growth attributes and the content of photosynthetic pigments were recorded. Moreover, the effect of drought stress on stomatal conductance and the photochemical efficiency of PSII (Fv/Fm) were followed. The data obtained indicated that the species of rice (Oryza sativa L.) cultivar Giza 177 under investigation was sensitive to drought stress where there were significant decreases in the fresh and dry weights of shoots and roots and in stomatal conductance, as well as in the content of chlorophyll a, chlorophyll b, and carotenoids. Seed priming with TRIA enhanced both growth and acquired plant tolerance to drought stress. Thus, TRIA via the enhancement of stomatal conductance through the regulation of stomatal closure, the rate of water loss, ABA metabolism, the accumulation of osmolytes, and the regulation of aquaporins genes improved the water status of plants grown under water scarcity. Moreover, TRIA via increasing the content of free amino acids and sugars under drought stress may increase the chance of plant tissues to retain more water under scarcity conditions.

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