scholarly journals Stress Responses of Shade-Treated Tea Leaves to High Light Exposure after Removal of Shading

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 302 ◽  
Author(s):  
Satoshi Sano ◽  
Tetsuyuki Takemoto ◽  
Akira Ogihara ◽  
Kengo Suzuki ◽  
Takehiro Masumura ◽  
...  
Keyword(s):  
Stress Responses ◽  
Light Exposure ◽  
Culture Method ◽  
High Light ◽  
Rapid Decline ◽  
Chl A ◽  
Oxidative Damages ◽  
Young Leaves ◽  
Antioxidant Defense Systems ◽  
Tea Plants

High-quality green tea is produced from buds and young leaves grown by the covering-culture method, which employs shading treatment for tea plants (Camellia sinensis L.). Shading treatment improves the quality of tea, but shaded tea plants undergo sudden exposures to high light (HL) at the end of the treatment by shade removal. In this study, the stress response of shaded tea plants to HL illumination was examined in field condition. Chl a/b ratio was lower in shaded plants than nonshaded control, but it increased due to exposure to HL after 14 days. Rapid decline in Fv/Fm values and increases in carbonylated protein level were induced by HL illumination in the shaded leaves on the first day, and they recovered thereafter between a period of one and two weeks. These results revealed that shaded tea plants temporarily suffered from oxidative damages caused by HL exposure, but they could also recover from these damages in 2 weeks. The activities of antioxidant enzymes, total ascorbate level, and ascorbate/dehydroascorbate ratio were decreased and increased in response to low light and HL conditions, respectively, suggesting that the upregulation of antioxidant defense systems plays a role in the protection of the shaded tea plants from HL stress.

scholarly journals Identifying Genes Involved in Alkaloid Biosynthesis in Vinca minor through Transcriptomics and Gene Co-Expression Analysis

Biomolecules ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1595
Author(s):  
Emily Amor Stander ◽  
Liuda Johana Sepúlveda ◽  
Thomas Dugé de Bernonville ◽  
Inês Carqueijeiro ◽  
Konstantinos Koudounas ◽  
...  
Keyword(s):  
Candidate Genes ◽  
Biosynthetic Pathway ◽  
Fluorescent Proteins ◽  
Light Exposure ◽  
Indole Alkaloids ◽  
High Light ◽  
Alkaloid Biosynthesis ◽  
Vinca Minor ◽  
Young Leaves ◽  
Derivatives Of

The lesser periwinkle Vinca minor accumulates numerous monoterpene indole alkaloids (MIAs) including the vasodilator vincamine. While the biosynthetic pathway of MIAs has been largely elucidated in other Apocynaceae such as Catharanthus roseus, the counterpart in V. minor remains mostly unknown, especially for reactions leading to MIAs specific to this plant. As a consequence, we generated a comprehensive V. minor transcriptome elaborated from eight distinct samples including roots, old and young leaves exposed to low or high light exposure conditions. This optimized resource exhibits an improved completeness compared to already published ones. Through homology-based searches using C. roseus genes as bait, we predicted candidate genes for all common steps of the MIA pathway as illustrated by the cloning of a tabersonine/vincadifformine 16-O-methyltransferase (Vm16OMT) isoform. The functional validation of this enzyme revealed its capacity of methylating 16-hydroxylated derivatives of tabersonine, vincadifformine and lochnericine with a Km 0.94 ± 0.06 µM for 16-hydroxytabersonine. Furthermore, by combining expression of fusions with yellow fluorescent proteins and interaction assays, we established that Vm16OMT is located in the cytosol and forms homodimers. Finally, a gene co-expression network was performed to identify candidate genes of the missing V. minor biosynthetic steps to guide MIA pathway elucidation.

High light stress reduces dinoflagellate predation on phytoplankton through both direct and indirect responses

2020 ◽  
Vol 84 ◽  
pp. 43-57
Author(s):  
SL Strom ◽  
O Barberi ◽  
C Mazur ◽  
K Bright ◽  
K Fredrickson
Keyword(s):  
Stress Responses ◽  
Physiological Condition ◽  
Light Exposure ◽  
Light Stress ◽  
High Light ◽  
Chemical Signaling ◽  
Predator Prey ◽  
Oxyrrhis Marina ◽  
Acquisition Strategies ◽  
Protist Species

This study investigated the influence of light stress on predator-prey interactions between phytoplankton and heterotrophic dinoflagellates. Among the studied phytoplankton species (dinoflagellates, cryptophytes, and prymnesiophytes), the coccolithophore Emiliania huxleyi was particularly sensitive to light stress, as evidenced by photosynthetic efficiency (Fv/Fm) responses and flow cytometry measures of physiological condition. In addition, E. huxleyi was the only studied prey species that experienced reduced dinoflagellate predation when light stressed: predation on stressed E. huxleyi decreased by an average of 49% relative to controls (range: 23-80%). These light stress and predation responses applied to both calcifying and non-calcifying E. huxleyi strains. High light exposure led to elevated production of dissolved dimethylsulfoniopropionate (DMSP) in one strain of E. huxleyi, a signal that was associated with decreased predation. Direct effects of light stress on the 2 dinoflagellate predators also differed. Predation by Amphidinium longum was strongly decreased by UV exposure, while predation by Oxyrrhis marina was largely unaffected. Our findings highlight the deep diversity that is characteristic of the planktonic protists, and point to chemical signaling as a means by which the effects of light stress can propagate into predation interactions. When defining the ecological niche of planktonic protist species, stress responses should be considered along with the resource acquisition strategies that support growth.

Photosynthetic responses of Coffea arabica leaves to a short-term high light exposure in relation to N availability

1997 ◽  
Vol 101 (1) ◽  
pp. 229-239 ◽  
Author(s):  
Jose C. Ramalho ◽  
Thos L. Pons ◽  
Henri W. Groeneveld ◽  
M. Antonieta Nunes
Keyword(s):  
Coffea Arabica ◽  
Light Exposure ◽  
High Light ◽  
N Availability ◽  
Short Term ◽  
Photosynthetic Responses

scholarly journals Comparative Tissue Responses of Marine Mollusks on Seasonal Changes in the Northern Adriatic Sea

2021 ◽  
Vol 11 (6) ◽  
pp. 2874
Author(s):  
Natalija Topić Popović ◽  
Martina Krbavčić ◽  
Josip Barišić ◽  
Blanka Beer Ljubić ◽  
Ivančica Strunjak-Perović ◽  
...  
Keyword(s):  
Stress Responses ◽  
Seasonal Variations ◽  
Antioxidant Defense ◽  
Winter Season ◽  
Northern Adriatic ◽  
Gonadal Maturation ◽  
Marine Mollusks ◽  
Significant Difference ◽  
Tissue Responses ◽  
Antioxidant Defense Systems

In the shallow Northern Adriatic, marine mollusks are affected by bottom trawling and seafood disturbance. Seasonal oscillations of oceanographic factors additionally influence their physiology, stress responses and survival. Tissue responses to seasonal variations in green ormer (Haliotis tuberculata L.) and Mediterranean scallop (Pecten jacobaeus L.) in the Northern Adriatic have not been reported. Hence, their biochemical and antioxidant defense properties over seasons were studied and the microanatomical structure of their tissue was correlated with function. Histological analysis of gonads revealed two peaks of gonadal maturation and spawning during the spring/summer period and winter season for scallops, and one peak during the fall for ormers. The gonadal maturation of both species was correlated with their seasonal variations of metabolic demands and antioxidant capacity. The lipid vacuoles of tubuloacinar terminations in the digestive gland differed between the two species; in scallop they are several-fold larger in size and number. Low temperatures in winter contributed to a decline in enzymatic antioxidant defense in scallop tissues, having lower superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity, and higher concentrations of thiobarbituric acid reactive substances (TBARS) and total antioxidant status (TAS). In ormers, winter induced lower TAS, TBARS, SOD and GPx concentrations. The significant difference of winter TAS and TBARS levels between ormers and scallops was correlated with variations in their reproductive cycles, as well as in antioxidant defense systems. The most important factor for stress-related parameters for both species in this work was found to be the season-induced temperature change.

scholarly journals Tolerance to water stress in boron-deficient tea (Camellia sinensis) plants

2012 ◽  
Vol 24 (1) ◽  
pp. 41-51 ◽  
Author(s):  
Roghieh Hajiboland ◽  
Soodabe Bastani
Keyword(s):  
Water Stress ◽  
Camellia Sinensis ◽  
Stress Conditions ◽  
Assimilation Rate ◽  
Antioxidant Defence System ◽  
Young Leaves ◽  
Net Assimilation ◽  
Single Stress ◽  
Tea Plants ◽  
Lower Ratio

Tolerance to water stress in boron-deficient tea (Camellia sinensis) plantsThe effects of boron (B) deficiency and water stress were studied in tea plants (Camellia sinensis[L.] O. Kuntze) grown in growth chambers in perlite irrigated with a nutrient solution. Dry matter production was reduced significantly by both low B supply and water stress. Shoot-root translocation of B declined in water-stressed plants. In addition, the re-translocation of B was impaired under drought, which was reflected in a significantly lower ratio of B content of young to old leaves in both B-deficient and B-sufficient plants. Leaf photochemical parameters were negatively influenced by B deficiency and water stress in the old but not in the young leaves. Although B-deficient plants were more conservative in relation to water loss following elevated stomatal limitation, their water potential was lower than in B-sufficient plants irrespective of the watering regime. Under the combined effects of B deficiency and water stress, the reduction in the CO2assimilation rate was more prominent than that under a single stress factor. The reduction of the net assimilation rate (A) in B-deficient plants due to water stress and in water-stressed plants due to low B supply were not accompanied by significant changes in the stomatal conductance, suggesting an involvement of non-stomatal factors. The activity of antioxidant enzymes and proline content increased under B deficiency and water stress conditions. Our results suggested that, in young leaves that have been developed under water stress, an acclimation to water stress conditions occurred that was well reflected in their more stable photochemistry, water relations and an efficient antioxidant defence system compared with the older leaves.

scholarly journals Glutathione and zeaxanthin formation during high light stress in foliose lichens

2008 ◽  
Vol 53 (No. 8) ◽  
pp. 340-344 ◽  
Author(s):  
J. Štepigová ◽  
H. Vráblíková ◽  
J. Lang ◽  
K. Večeřová ◽  
M. Barták
Keyword(s):  
Xanthophyll Cycle ◽  
Light Exposure ◽  
Light Stress ◽  
High Light ◽  
Short Term ◽  
Xanthophyll Cycle Pigments ◽  
High Light Stress ◽  
Fluorescence Label ◽  
Thiol Binding ◽  
Pure Acetone

In the presented study, we describe techniques for glutathione and pigment determination in lichens used in our laboratory. Glutathione and xanthophyll cycle pigments, especially zeaxanthin, are important antioxidants protecting plants against various stresses. In our laboratory, the high light stress in lichens has been intensively studied for several years. We extract glutathione in HCl and determine it by thiol-binding fluorescence label monobromobimane. For pigment determination, homogenized lichen thalli are extracted with pure acetone. According to our results, the total amount of glutathione decreases after a short-term high light exposure, while the amount of zeaxanthin increases.

scholarly journals Acute Stress Responses Are Early Molecular Events of Retinal Degeneration inAbca4−/−Rdh8−/−Mice After Light Exposure

2016 ◽  
Vol 57 (7) ◽  
pp. 3257 ◽  
Author(s):  
Tanu Parmar ◽  
Vipul M. Parmar ◽  
Eisuke Arai ◽  
Bhubanananda Sahu ◽  
Lindsay Perusek ◽  
...  
Keyword(s):  
Retinal Degeneration ◽  
Stress Responses ◽  
Acute Stress ◽  
Light Exposure ◽  
Molecular Events

scholarly journals Allelopathy in a Leguminous Mangrove Plant, Derris indica: Protoplast Co-culture Bioassay and Rotenone Effect

2015 ◽  
Vol 10 (5) ◽  
pp. 1934578X1501000 ◽  
Author(s):  
Aya Inoue ◽  
Daisuke Mori ◽  
Reiko Minagawa ◽  
Yoshiharu Fujii ◽  
Hamako Sasamoto
Keyword(s):  
Suspension Culture ◽  
Basal Medium ◽  
Culture Method ◽  
Mangrove Plant ◽  
Lettuce Seedling ◽  
Mannitol Solution ◽  
Allelopathic Activity ◽  
Young Leaves ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Derris Indica

To investigate allelopathic activity of a leguminous mangrove plant, Derris indica, the ‘Protoplasts Co-culture Method’ for bioassay of allelopathy was developed using suspension culture. A suspension culture was induced from immature seed and sub-cultured in Murashige and Skoog's (MS) basal medium containing 10 μM each of 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzyladenine (BA). The protoplasts were isolated using the separate wells method with 2% each of Cellulase RS, Driselase 20 and Macerozyme R10 in 0.4 M mannitol solution. Protoplast cultures of D. indica revealed that high concentrations of cytokinins, BA and thidiazuron, were effective for cell divisions. The co-cultures of D. indica protoplasts with recipient lettuce protoplasts using 96 multi-well culture plates were performed in MS basal medium containing 0.4 M mannitol solution and 1 μM 2,4-D and 0.1 μM BA. The protoplast density of D. indica used in co-culturing varied from 6 × 103 - 105 / mL. Very strong inhibitory allelopathic effects of D. indica protoplasts on lettuce protoplast growth were found. A similar strong inhibitory allelopathic activity of dried young leaves on lettuce seedling growth was also observed by using the sandwich method. Rotenone, which is a component of Derris root, dissolved in DMSO, was highly inhibitory on the growth of lettuce protoplasts in culture and this could be one of the causes of the strong allelopathic activity of D. indica.

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