Seasonal photosynthesis and anthocyanin production in 10 broadleaf evergreen species

Leaves of many evergreen species turn red when exposed to high sunlight during winter due to production of photoprotective anthocyanin pigments, while leaves of other species, lacking anthocyanin, remain green. Why some evergreen species synthesise anthocyanin pigments while others do not is currently unknown. Furthermore, the relative photosynthetic performance of anthocyanic (red) and acyanic (green) evergreens has yet to be described. Here we present seasonal ecophysiological data for five red and green broadleaf evergreen species. We hypothesise that species which synthesise anthocyanins in winter leaves correspond to those with the most drastic seasonal photosynthetic declines, as reduced energy sinks increase vulnerability to photoinhibition and need for photoprotection. Our results did not support this hypothesis, as gas exchange measurements showed no difference in mean seasonal photosynthetic capacity between red- and green-leafed species. Consistent with anthocyanin’s shading effect, red-leafed species had significantly higher chlorophyll content, lower chlorophyll a/b ratios, and higher maximum light capture efficiency of PSII (Fv/Fm) than green-leafed species during the winter, but not during the summer (when all leaves were green). We conclude that anthocyanin production during winter is likely not associated with diminished photosynthetic capacity, and may simply represent an alternative photoprotective strategy utilised by some species during winter.

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Photosynthetic Performance of Guaranazeiro Plants as Affected by Glyphosate Application

Journal of Agricultural Science ◽

10.5539/jas.v12n10p287 ◽

2020 ◽

Vol 12 (10) ◽

pp. 287

Author(s):

Bruna N. Leite ◽

Karla Gabrielle D. Pinto ◽

Victor Alexandre H. F. dos Santos ◽

Marciel J. Ferreira ◽

Sônia Maria F. Albertino

Keyword(s):

Gas Exchange ◽

Chlorophyll Content ◽

Photosynthetic Performance ◽

Productive Performance ◽

Weed Species ◽

Short Term ◽

Paullinia Cupana ◽

Process Gas ◽

Quantum Efficiency Of Psii ◽

Relative Chlorophyll Content

The unsuitable use of herbicides damages many cultures. In cases of high infestations and presence of aggressive weed species in guarana (Paullinia cupana) culture, glyphosate application is advisable, but its impact on guarana physiology is unknown. Therefore, leaf photosynthetic characteristics were measured with the aim of identifying if the photosynthetic performance of guaranazeiro plants is affected in response to glyphosate application. Three glyphosate doses (0 (control); 324 and 432 g a.i. ha-1) were applied to two guaranazeiro cultivars (BRS-Andirá and BRS-Maués) selected on the basis of productive performance. An analysis was made of the effects of these doses on characteristics that represent the photosynthetic process: gas exchange, maximum quantum efficiency of PSII, performance index and chlorophyll content. The application of glyphosate did not affect the short-term responses relative chlorophyll content (SPAD index) and light use (chlorophyll a fluorescence). After 168 h, there were changes only in gas exchange variables. The effects of glyphosate doses on gas exchange was different between guaranazeiro cultivars. The photosynthetic performance of the guaranazeiro seems to be tolerant to the effects of short-term of glyphosate application.

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Light spectrum affects growth and gas exchange of common dandelion and purple coneflower seedlings

International Journal of Plant Biology ◽

10.4081/pb.2016.6281 ◽

2016 ◽

Vol 7 (1) ◽

Author(s):

Donato Castronuovo ◽

Adriano Sofo ◽

Stella Lovelli ◽

Vincenzo Candido ◽

Antonio Scopa

Keyword(s):

Gas Exchange ◽

Chlorophyll Content ◽

Experimental Period ◽

Photosynthetic Performance ◽

Controlled Environment ◽

Artificial Light ◽

Light Sources ◽

Light Spectrum ◽

Purple Coneflower ◽

Common Dandelion

Artificial light, supplied by fluorescent lamps, has been effectively utilized in controlled- environment chambers for horticulture and floriculture nursery. This experiment aimed at investigating whether light-emitting diodes (LEDs) have the same effectiveness on plant morphology, photosynthetic and physiological responses as FLUORA lamps. Seedlings of common dandelion (Taraxacum officinale) and purple coneflower (Echinacea purpurea), species of high interest for their nutraceutical properties, were grown in controlled-environment chambers for 50 days under LED and FLUORA light sources as sole-source lighting systems, and the effects of artificial light supplies on plant photosynthetic performance and chlorophyll content (SPAD) were evaluated. The results were compared to plants grown under natural sunlight. In both species, total chlorophyll content (SPAD) values decreased for plants under sunlight, and for those grown under FLUORA lighting throughout the experimental period, while the values measured for plants grown under LEDs maintained a relatively constant value. At the end of the experiment, plant dry matter in both species was significantly lower under LEDs and FLUORA lighting, than the plants exposed to solar light. The two species showed different gas exchange dynamics under LEDs and FLUORA lighting, and photosynthetic performance decreasing after 10 days of light treatment compared to plants under sunlight. The results demonstrated that for common dandelion and purple coneflower photosynthetic processes are often modified when the species are cultivated under these artificial lighting and in controlled- environment chambers, because lamps do not able to generate the same spectrum and energy of sunlight.

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Anatomy, chlorophyll content and photosynthetic performance in current-year and previous-year Aleppo pine (Pinus halepensis Mill.) needles

Botanica Serbica ◽

10.2298/botserb2001061t ◽

2020 ◽

Vol 44 (1) ◽

pp. 61-69 ◽

Cited By ~ 1

Author(s):

Tomo Trstenjak ◽

Antunovic Dunic ◽

Selma Mlinaric ◽

Lidija Begovic ◽

Marin Skoro ◽

...

Keyword(s):

Chlorophyll Content ◽

Chlorophyll A ◽

Pinus Halepensis ◽

Woody Species ◽

Photosynthetic Performance ◽

Aleppo Pine ◽

Resin Duct ◽

Chlorophylls A And B ◽

Crown Defoliation ◽

Significant Difference

Aleppo pine (Pinus halepensis) is a widespread Mediterranean woody species. Needles usually fall off the tree after the second year, which can be the reason for substantial crown defoliation under extreme environmental stress. The aim of the present investigation was to compare the anatomy, chlorophyll content and photosynthetic performance in current-year (CY) and previous-year (PY) Aleppo pine needles. Chlorophyll concentrations were determined spectrophotometrically, while photosynthetic performance was determined by measuring the increase in chlorophyll a fluorescence (the JIP test). The obtained results revealed that concentrations of chlorophylls a and b were almost twice as great in PY needles as in CY ones. The chlorophyll a to b ratio and values of the maximum quantum yield of photosystem II (Fv/Fm) showed no statistically significant difference between CY and PY needles. However, the performance index (PIABS) was significantly higher in CY needles compared to PY ones. Analysis of PIABS components revealed that CY needles had increased electron transport beyond the primary electron acceptor, QA -, which was associated with a lower value of variable fluorescence at 2 ms (VJ) in comparison with PY needles. Also, some differences were observed in needle anatomy. Current-year needles had an increased proportion of mesophyll tissue, together with decreased proportions of vascular cylinder and resin duct areas. Also, many more starch grains were present in PY than in CY needles. Based on the presented results, it can be concluded that despite considerably lower chlorophyll content, CY needles exhibited photosynthetic performance better than that of older needles, which is an unusual phenomenon in woody species.

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Estimation of chlorophyll content by absorption spectra of native Spirulina platensis cells

Issues of modern algology (Вопросы современной альгологии) ◽

10.33624/2311-0147-2020-1(22)-25-33 ◽

2020 ◽

pp. 25-33

Author(s):

Leonid E. Paramonov

Keyword(s):

Chlorophyll Content ◽

Chlorophyll A ◽

Absorption Spectra ◽

Spirulina Platensis ◽

Intracellular Concentration ◽

Absorption Coefficients

A method for retrieving the absorption coefficients of Spirulina platensis pigments using absorption spectra of native cells and excluding the use of extracts is considered. Estimates of the intracellular concentration of chlorophyll a, С-phycoerythrin, С- phycocyanin and allophycocyanin in native cells are discussed.

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Shading Effects on Leaf Gas Exchange, Leaf Pigments and Secondary Metabolites of Polygonum minus Huds., an Aromatic Medicinal Herb

Plants ◽

10.3390/plants10030608 ◽

2021 ◽

Vol 10 (3) ◽

pp. 608

Author(s):

Fairuz Fatini Mohd Yusof ◽

Jamilah Syafawati Yaacob ◽

Normaniza Osman ◽

Mohd Hafiz Ibrahim ◽

Wan Abd Al Qadr Imad Wan-Mohtar ◽

...

Keyword(s):

Gas Exchange ◽

Secondary Metabolites ◽

Chlorophyll A ◽

Leaf Gas Exchange ◽

Photosynthesis Rate ◽

Total Phenolic ◽

Chlorophyll B ◽

Low Light ◽

Total Anthocyanin ◽

Polygonum Minus

The growing demand for high value aromatic herb Polygonum minus-based products have increased in recent years, for its antioxidant, anticancer, antimicrobial, and anti-inflammatory potentials. Although few reports have indicated the chemical profiles and antioxidative effects of Polygonum minus, no study has been conducted to assess the benefits of micro-environmental manipulation (different shading levels) on the growth, leaf gas exchange and secondary metabolites in Polygonum minus. Therefore, two shading levels (50%:T2 and 70%:T3) and one absolute control (0%:T1) were studied under eight weeks and 16 weeks of exposures on Polygonum minus after two weeks. It was found that P. minus under T2 obtained the highest photosynthesis rate (14.892 µmol CO2 m−2 s−1), followed by T3 = T1. The increase in photosynthesis rate was contributed by the enhancement of the leaf pigments content (chlorophyll a and chlorophyll b). This was shown by the positive significant correlations observed between photosynthesis rate with chlorophyll a (r2 = 0.536; p ≤ 0.05) and chlorophyll b (r2 = 0.540; p ≤ 0.05). As the shading levels and time interval increased, the production of total anthocyanin content (TAC) and antioxidant properties of Ferric Reducing Antioxidant Power (FRAP) and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) also increased. The total phenolic content (TPC) and total flavonoid content (TFC) were also significantly enhanced under T2 and T3. The current study suggested that P.minus induce the production of more leaf pigments and secondary metabolites as their special adaptation mechanism under low light condition. Although the biomass was affected under low light, the purpose of conducting the study to boost the bioactive properties in Polygonum minus has been fulfilled by 50% shading under 16 weeks’ exposure.

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The Optical Properties of Leaf Structural Elements and Their Contribution to Photosynthetic Performance and Photoprotection

Plants ◽

10.3390/plants10071455 ◽

2021 ◽

Vol 10 (7) ◽

pp. 1455

Author(s):

George Karabourniotis ◽

Georgios Liakopoulos ◽

Panagiota Bresta ◽

Dimosthenis Nikolopoulos

Keyword(s):

Glandular Trichomes ◽

Spectral Band ◽

Co2 Assimilation ◽

Photosynthetic Performance ◽

Structural Elements ◽

Internal Layers ◽

Water Losses ◽

Light Gradient ◽

Propagation Of Light ◽

Light Capture

Leaves have evolved to effectively harvest light, and, in parallel, to balance photosynthetic CO2 assimilation with water losses. At times, leaves must operate under light limiting conditions while at other instances (temporally distant or even within seconds), the same leaves must modulate light capture to avoid photoinhibition and achieve a uniform internal light gradient. The light-harvesting capacity and the photosynthetic performance of a given leaf are both determined by the organization and the properties of its structural elements, with some of these having evolved as adaptations to stressful environments. In this respect, the present review focuses on the optical roles of particular leaf structural elements (the light capture module) while integrating their involvement in other important functional modules. Superficial leaf tissues (epidermis including cuticle) and structures (epidermal appendages such as trichomes) play a crucial role against light interception. The epidermis, together with the cuticle, behaves as a reflector, as a selective UV filter and, in some cases, each epidermal cell acts as a lens focusing light to the interior. Non glandular trichomes reflect a considerable part of the solar radiation and absorb mainly in the UV spectral band. Mesophyll photosynthetic tissues and biominerals are involved in the efficient propagation of light within the mesophyll. Bundle sheath extensions and sclereids transfer light to internal layers of the mesophyll, particularly important in thick and compact leaves or in leaves with a flutter habit. All of the aforementioned structural elements have been typically optimized during evolution for multiple functions, thus offering adaptive advantages in challenging environments. Hence, each particular leaf design incorporates suitable optical traits advantageously and cost-effectively with the other fundamental functions of the leaf.

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