scholarly journals Morphological and Photosynthetic Response to High and Low Irradiance ofAeschynanthus longicaulis

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Qiansheng Li ◽  
Min Deng ◽  
Yanshi Xiong ◽  
Allen Coombes ◽  
Wei Zhao
Keyword(s):  
Light Stress ◽  
High Irradiance ◽  
Anthocyanin Content ◽  
Light Conditions ◽  
Leaf Color ◽  
Low Light ◽  
Light Levels ◽  
Chlorophyll Fluorescence Parameter ◽  
Fluorescence Parameter ◽  
Length Width

Aeschynanthus longicaulisplants are understory plants in the forest, adapting to low light conditions in their native habitats. To observe the effects of the high irradiance on growth and physiology, plants were grown under two different light levels, PPFD 650 μmol·m–2·s–1and 150 μmol·m–2·s–1for 6 months. Plants under high irradiance had significantly thicker leaves with smaller leaf area, length, width, and perimeter compared to the plants grown under low irradiance. Under high irradiance, the leaf color turned yellowish and the total chlorophyll decreased from 5.081 mg·dm−2to 3.367 mg·dm−2. The anthocyanin content of high irradiance leaves was double that of those under low irradiance. The plants under high irradiance had significantly lower Amax(5.69 μmol·m–2·s–1) and LSP (367 μmol·m–2·s–1) and higher LCP (21.9 μmol·m–2·s–1). The chlorophyll fluorescence parameterFv/Fmwas significantly lower and NPQ was significantly higher in high irradiance plants. RLCs showed significantly lowerETRmax⁡andEkin plants under high irradiance. It can be concluded that the maximum PPFD of 650 μmol·m–2·s–1led to significant light stress and photoinhibition ofA. longicaulis.

scholarly journals A chloroplast thylakoid lumen protein is required for proper photosynthetic acclimation of plants under fluctuating light environments

2017 ◽  
Vol 114 (38) ◽  
pp. E8110-E8117 ◽  
Author(s):  
Jun Liu ◽  
Robert L. Last
Keyword(s):  
Photosystem Ii ◽  
Light Stress ◽  
High Irradiance ◽  
Light Conditions ◽  
Agricultural Plant ◽  
Photosynthetic Organisms ◽  
Fluctuating Light ◽  
Stress Susceptibility ◽  
Efficiency And Productivity ◽  
Photosynthetic Adaptation

Despite our increasingly sophisticated understanding of mechanisms ensuring efficient photosynthesis under laboratory-controlled light conditions, less is known about the regulation of photosynthesis under fluctuating light. This is important because—in nature—photosynthetic organisms experience rapid and extreme changes in sunlight, potentially causing deleterious effects on photosynthetic efficiency and productivity. Here we report that the chloroplast thylakoid lumenal protein MAINTENANCE OF PHOTOSYSTEM II UNDER HIGH LIGHT 2 (MPH2; encoded byAt4g02530) is required for growth acclimation ofArabidopsis thalianaplants under controlled photoinhibitory light and fluctuating light environments. Evidence is presented thatmph2mutant light stress susceptibility results from a defect in photosystem II (PSII) repair, and our results are consistent with the hypothesis that MPH2 is involved in disassembling monomeric complexes during regeneration of dimeric functional PSII supercomplexes. Moreover,mph2—and previously characterized PSII repair-defective mutants—exhibited reduced growth under fluctuating light conditions, while PSII photoprotection-impaired mutants did not. These findings suggest that repair is not only required for PSII maintenance under static high-irradiance light conditions but is also a regulatory mechanism facilitating photosynthetic adaptation under fluctuating light environments. This work has implications for improvement of agricultural plant productivity through engineering PSII repair.

Does Astaxanthin Protect Haematococcus against Light Damage?

1998 ◽  
Vol 53 (1-2) ◽  
pp. 93-100 ◽  
Author(s):  
Lu Fan ◽  
Avigad Vonshak ◽  
Aliza Zarka ◽  
Sammy Boussiba
Keyword(s):  
Light Intensity ◽  
Light Stress ◽  
Phosphate Starvation ◽  
High Light Intensity ◽  
High Irradiance ◽  
High Light ◽  
Protective Agent ◽  
Light Damage ◽  
Low Light ◽  
Very High

Abstract The photoprotective function of the ketocarotenoid astaxanthin in Haematococcus was questioned. When exposed to high irradiance and/or nutritional stress, green Haematococcus cells turned red due to accumulation of an immense quantity of the red pigment astaxanthin. Our results demonstrate that: 1) The addition of diphenylamine, an inhibitor of astaxanthin biosynthesis, causes cell death under high light intensity; 2) Red cells are susceptible to high light stress to the same extent or even higher then green ones upon exposure to a very high light intensity (4000 μmol photon m-2 s-1); 3) Addition of 1O2 generators (methylene blue, rose bengal) under noninductive conditions (low light of 100 (μmol photon m-2 s-1) induced astaxanthin accumulation. This can be reversed by an exogenous 1O2 quencher (histidine); 4) Histidine can prevent the accumulation of astaxanthin induced by phosphate starvation. We suggest that: 1) Astaxanthin is the result of the photoprotection process rather than the protective agent; 2) 1O2 is involved indirectly in astaxanthin accumulation process.

Phenotypic flexibility and genetic adaptation along a gradient of secondary forest succession in the grass Danthonia spicata

1986 ◽  
Vol 64 (4) ◽  
pp. 739-747 ◽  
Author(s):  
Samuel M. Scheiner ◽  
James A. Teeri
Keyword(s):  
Forest Succession ◽  
Secondary Forest ◽  
Moisture Gradient ◽  
Pine Forests ◽  
Genetic Adaptation ◽  
Phenotypic Flexibility ◽  
Light Conditions ◽  
Low Light ◽  
Light Levels ◽  
Danthonia Spicata

Populations of Danthonia spicata were studied from sites of ages 0, 26, 32, 44, and 69 years after fire in the aspen–pine forests of northern lower Michigan. Along this gradient the environment changes from unshaded and dry to a shaded, moist pine and hardwood forest. Greenhouse treatments and transplant gardens were used to investigate the extent to which phenotypic flexibility and genetic adaptation were responsible for the persistence of D. spicata across this light and soil moisture gradient. With regard to phenotypic flexibility, we found that individual plants of D. spicata can grow and reproduce in light levels lower than those found at any site in the field. The populations were genetically distinct from each other but the differences were small relative to the range of phenotypic flexibility. Some populations and individuals performed better under high light conditions and all individuals performed equally poorly under low light conditions. A multivariate analysis suggests that genetic drift may have been more important than selection in differentiating the populations. Phenotypic flexibility was shown to be more important than genetic adaptation in explaining the persistence of D. spicata along the successional gradient.

scholarly journals Biomass allocation of chestnut oak (Quercus castaneifolia C.A. Mey) seedlings: effects of provenance and light gradient

2014 ◽  
Vol 60 (No. 11) ◽  
pp. 443-450 ◽  
Author(s):  
F. Babaei Sustani ◽  
S.G. Jalali ◽  
H. Sohrabi ◽  
A. Shirvani
Keyword(s):  
Biomass Allocation ◽  
Leaf Size ◽  
Growth Conditions ◽  
High Irradiance ◽  
Growth Strategies ◽  
Low Light ◽  
Rainfall Gradient ◽  
Light Levels ◽  
Light Gradient ◽  
Precipitation Regimes

Patterns of biomass allocation were determined for seedlings of five provenances of Quercus castaneifolia from west to east of the Hyrcanian forest along a rainfall gradient. Experimental design was executed under controlled conditions at seven different light levels (10, 20, 30, 40, 50, 60, 70 and 100% full light). We quantified the biomass allocation patterns to leaves, stems and roots. For all provenances total mass increased with irradiance at low light levels, reaching an optimum at an intermediate level but decreasing at a high irradiance level. As results show, in drier provenances and at high light levels, the seedlings invest more biomass into root mass to facilitate water uptake and to alter their leaf size to prevent overheating. In contrast, at wetter provenances and low light levels, towards increased light interception, more biomass is allocated proportionally to leaves and the stems but, accordingly, less to roots. The leaf to root ratio (L/R) was negatively correlated with light, with high correlation at wetter provenances compared to drier ones. In contrast, the relationship between the root to shoot (R/Sh) ratio and light was positively correlated with light, but it was weak at drier provenances and became gradually stronger at wetter ones. Such relationships indicated that chestnut oak seedling growth strategies are different along a rainfall gradient to irradiance levels. Despite similar growth conditions in the greenhouse, different growth strategies may be the result of genetic adaptation to the ecological conditions, especially when precipitation regimes prevail in the native habitat.  

scholarly journals Degradation of the Light-Stress Protein is Mediated by an ATP-Independent, Serine-Type Protease Under Low-Light Conditions

1996 ◽  
Vol 236 (2) ◽  
pp. 591-599 ◽  
Author(s):  
Iwona Adamska ◽  
Marika Lindahl ◽  
Margrit Roobol-Boza ◽  
Bertil Andersson
Keyword(s):  
Light Stress ◽  
Stress Protein ◽  
Light Conditions ◽  
Low Light

scholarly journals Inhibitory Effects of Oyster Shell on the Spathe “Greenback” of Anthurium andraeanum Lind.

2019 ◽  
Vol 131 ◽  
pp. 01108
Author(s):  
Chun-hua Xia ◽  
Yi-wei Chen ◽  
Jian-hua Chen
Keyword(s):  
Sugar Content ◽  
Soluble Sugar ◽  
Oyster Shell ◽  
Anthocyanin Content ◽  
Light Conditions ◽  
Low Light ◽  
Pal Activity ◽  
Cultivation Technique ◽  
Anthurium Andraeanum ◽  
Shell Fragments

Anthurium andraeanum Lind. is an important tropical flower. However, the spathe of A. andraeanum develops a ”greenback” under low-light conditions. This study aimed to evaluate the use of oyster shell supplementation as a cultivation technique for inhibiting the spathe “greenback” of A. andraeanum under low-light conditions. Appropriate calcium from micro-dissolution of oyster shell can improve the activity of phenylalanine ammonia lyase (PAL) which is positively correlated with the anthocyanin content. Using regression models and response surface methodology (RSM), the relationships between oyster shell fragments and the anthocyanin content were determined. The results showed that the solubility of oyster shells increased with the increase in fragment weight, C, and time, T at pH 5.9. In oyster shell substrate, cultivation of A. andraeanum under low-light conditions (less than 220 μmol·m−2·s−1) at pH 5.9, regression analysis showed that the PAL activity in pedicels of A. andraeanum first increased and then decreased with the increase in oyster shell fragment weight C, and the 286 mg oyster shell fragments greatly increased the PAL activity of A. andraeanum pedicels within 8 weeks (w). The 286 mg oyster shell fragments significantly increased the anthocyanin content in A. andraeanum spathes under weak-light conditions within 8 h, and the soluble sugar content reached the maximum value at 15 weeks as well, together with the pedicel diameter, soluble sugar and water content, thus inhibiting the spathe “greenback” of A. andraeanum.

scholarly journals Defoliation Significantly Suppressed Plant Growth Under Low Light Conditions in Two Leguminosae Species

2022 ◽  
Vol 12 ◽  
Author(s):  
Ning Wang ◽  
Tianyu Ji ◽  
Xiao Liu ◽  
Qiang Li ◽  
Kulihong Sairebieli ◽  
...  
Keyword(s):  
Plant Growth ◽  
Combined Treatment ◽  
Chlorophyll Concentration ◽  
Light Stress ◽  
Early Period ◽  
Light Treatment ◽  
High Light ◽  
Herbivorous Insects ◽  
Light Conditions ◽  
Low Light

Seedlings in regenerating layer are frequently attacked by herbivorous insects, while the combined effects of defoliation and shading are not fully understood. In the present study, two Leguminosae species (Robinia pseudoacacia and Amorpha fruticosa) were selected to study their responses to combined light and defoliation treatments. In a greenhouse experiment, light treatments (L+, 88% vs L−, 8% full sunlight) and defoliation treatments (CK, without defoliation vs DE, defoliation 50% of the upper crown) were applied at the same time. The seedlings’ physiological and growth traits were determined at 1, 10, 30, and 70 days after the combined treatment. Our results showed that the effects of defoliation on growth and carbon allocation under high light treatments in both species were mainly concentrated in the early stage (days 1–10). R. pseudoacacia can achieve growth recovery within 10 days after defoliation, while A. fruticosa needs 30 days. Seedlings increased SLA and total chlorophyll concentration to improve light capture efficiency under low light treatments in both species, at the expense of reduced leaf thickness and leaf lignin concentration. The negative effects of defoliation treatment on plant growth and non-structural carbohydrates (NSCs) concentration in low light treatment were significantly higher than that in high light treatment after recovery for 70 days in R. pseudoacacia, suggesting sufficient production of carbohydrate would be crucial for seedling growth after defoliation. Plant growth was more sensitive to defoliation and low light stress than photosynthesis, resulting in NSCs accumulating during the early period of treatment. These results illustrated that although seedlings could adjust their resource allocation strategy and carbon dynamics in response to combined defoliation and light treatments, individuals grown in low light conditions will be more suppressed by defoliation. Our results indicate that we should pay more attention to understory seedlings’ regeneration under the pressure of herbivorous insects.

scholarly journals Postharvest Handling of Cut Campanula medium Flowers

HortScience ◽  
2002 ◽  
Vol 37 (6) ◽  
pp. 954-958 ◽  
Author(s):  
Theresa Bosma ◽  
John M. Dole
Keyword(s):  
Sucrose Concentration ◽  
High Light ◽  
Deionized Water ◽  
Vase Life ◽  
Light Conditions ◽  
Low Light ◽  
Storage Duration ◽  
Light Levels ◽  
Postharvest Handling

Various postharvest treatments were evaluated for effect on longevity and quality of cut Campanula medium L. `Champion Blue' and `Champion Pink' stems. Stems stored at 2 °C either wet or dry had no difference in vase life or percent flowers opened; however, flowers stored dry had a slightly greater percentage of senesced flowers at termination. Increasing storage duration from 1 to 3 weeks decreased vase life. Stems pretreated for 4 hours with 38 °C floral solution (deionized water amended to pH 3.5 with citric acid and 200 mg·L-1 8-HQC) or a 1-MCP pulse followed by a 5% sucrose pulse solution produced the longest vase life (10.3 or 10.4 days, respectively). Flowers opening after treatments commenced were paler than those flowers already opened and a 24-hour pretreatment with 5% or 10% sucrose did not prevent this color reduction. Stems had an average vase life of only 3.3 days when placed in floral vase foam but lasted 10.0 days without foam. Optimum sucrose concentration was 1.0% to 2.0% for stems placed in 22 °C floral vase solution without foam and 4% for stems placed in foam. High (110 μmol·m-2·s-1) or low (10 μmol·m-2·s-1) light levels did not affect postharvest parameters, but the most recently opened flowers were paler under low light conditions than under high light conditions. Chemical names used: 8-hydroxyquinoline citrate (8-HQC); 1-methylcyclopropene (1-MCP).

scholarly journals Inactivation of Genes Encoding Plastoglobulin-Like Proteins in Synechocystis sp. PCC 6803 Leads to a Light-Sensitive Phenotype

2010 ◽  
Vol 192 (6) ◽  
pp. 1700-1709 ◽  
Author(s):  
Francis X. Cunningham ◽  
Ashley B. Tice ◽  
Christina Pham ◽  
Elisabeth Gantt
Keyword(s):  
Inclusion Bodies ◽  
Light Stress ◽  
High Irradiance ◽  
Oxygenic Photosynthesis ◽  
Wild Type ◽  
Fundamental Function ◽  
Low Light ◽  
Photooxidative Damage ◽  
Genes Encoding ◽  
Pcc 6803

ABSTRACT Plastoglobulins (PGL) are the predominant proteins of lipid globules in the plastids of flowering plants. Genes encoding proteins similar to plant PGL are also present in algae and cyanobacteria but in no other organisms, suggesting an important role for these proteins in oxygenic photosynthesis. To gain an understanding of the core and fundamental function of PGL, the two genes that encode PGL-like polypeptides in the cyanobacterium Synechocystis sp. PCC 6803 (pgl1 and pgl2) were inactivated individually and in combination. The resulting mutants were able to grow under photoautotrophic conditions, dividing at rates that were comparable to that of the wild-type (WT) under low-light (LL) conditions (10 microeinsteins·m−2·s−1) but lower than that of the WT under moderately high-irradiance (HL) conditions (150 microeinsteins·m−2·s−1). Under HL, each Δpgl mutant had less chlorophyll, a lower photosystem I (PSI)/PSII ratio, more carotenoid per unit of chlorophyll, and very much more myxoxanthophyll (a carotenoid symptomatic of high light stress) per unit of chlorophyll than the WT. Large, heterogeneous inclusion bodies were observed in cells of mutants inactivated in pgl2 or both pgl2 and pgl1 under both LL and HL conditions. The mutant inactivated in both pgl genes was especially sensitive to the light environment, with alterations in pigmentation, heterogeneous inclusion bodies, and a lower PSI/PSII ratio than the WT even for cultures grown under LL conditions. The WT cultures grown under HL contained 2- to 3-fold more PGL1 and PGL2 per cell than cultures grown under LL conditions. These and other observations led us to conclude that the PGL-like polypeptides of Synechocystis play similar but not identical roles in some process relevant to the repair of photooxidative damage.

scholarly journals Epistatic Interactions Influencing Anthocyanin Gene Expression in Capsicum annuum

2007 ◽  
Vol 132 (6) ◽  
pp. 824-829 ◽  
Author(s):  
Gordon J. Lightbourn ◽  
John R. Stommel ◽  
Robert J. Griesbach
Keyword(s):  
Gene Expression ◽  
Light Intensity ◽  
Genetic Basis ◽  
High Light ◽  
Anthocyanin Content ◽  
Anthocyanin Accumulation ◽  
Light Conditions ◽  
Low Light ◽  
Mature Leaves ◽  
Anthocyanin Concentration

Anthocyanin pigmentation in leaves, flowers, and fruit imparts violet to black color and enhances both ornamental and culinary appeal. Shades of violet to black pigmentation in Capsicum annuum L. are attributed to anthocyanin accumulation. Anthocyanin production is markedly influenced by numerous environmental factors, including temperature and light stress. The objective of this study was to determine the genetic basis for differences in C. annuum anthocyanin content in response to varying environments. Growth experiments conducted under controlled environment conditions demonstrated that anthocyanin concentration was significantly higher in mature leaves in comparison with immature leaves under high light (435 μmol·s−1·m−2) conditions. High (30 °C day/25 °C night) versus low (20 °C day/15 °C night) temperature had no significant effect on anthocyanin concentration regardless of leaf maturity stage. Foliar anthocyanin concentration in plants grown under short days (10 h) with low light intensity (215 μmol·s−1·m−2) was significantly less than under long days (16 h) with low light. Under high light intensity, daylength had no effect on anthocyanin content. Three structural genes [chalcone synthase (Chs), dihydroflavonol reductase (Dfr), anthocyanin synthase (Ans)] and three regulatory genes (Myc, MybA , Wd40) were selected for comparison under inductive and noninductive environmental conditions for anthocyanin accumulation. Expression of Chs, Dfr, and Ans was significantly higher in mature leaves in comparison with younger leaves. Consistent with anthocyanin concentration, temperature had no effect on structural gene expression, whereas light positively influenced expression. Under low light conditions, temperature had no effect on Myc, MybA , and Wd40 expression; whereas under high light conditions, temperature only had an effect on MybA expression. The study of anthocyanin leaf pigmentation in C. annuum under inductive and noninductive environments provides a new approach for elucidating the molecular genetic basis of epistatic gene interactions and the resulting phenotypic plasticity.

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