The sun-exposed peel of apple fruit has a higher photosynthetic capacity than the shaded peel

2007 ◽  
Vol 34 (11) ◽  
pp. 1038 ◽  
Author(s):  
Li-Song Chen ◽  
Lailiang Cheng
Keyword(s):  
Chlorophyll Fluorescence ◽  
Electron Transport ◽  
Oxygen Evolution ◽  
Photosynthetic Capacity ◽  
Light Exposure ◽  
Calvin Cycle ◽  
Apple Fruit ◽  
Thermal Dissipation ◽  
The Sun ◽  
Significant Difference

To determine whether the sun-exposed peel of apple fruit has a higher photosynthetic capacity than the shaded peel, fruit peel samples were taken in both early July and early September from the exterior part of the canopy of mature ‘Liberty’/M.9 trees for measuring oxygen evolution, key enzymes and metabolites involved in photosynthesis, and chlorophyll fluorescence. Compared with the shaded peel, the sun-exposed peel had higher light-saturated oxygen evolution rate and higher light saturation point, but lower apparent and true quantum yields. The activity of ribulose-1,5-bisphosphate carboxylase/oxygenase, glyceraldehyde-3-phosphate dehydrogenase, phosphoribulokinase, stromal fructose-1,6-bisphosphatase, ADP-glucose pyrophosphorylase and sucrose-phosphate synthase (SPS) were higher in the sun-exposed peel than in the shaded peel on both sampling dates except that no significant difference was found in SPS activity between the two peel types in September. No significant difference was detected in the concentration of key metabolites (G6P, F6P, G1P, and PGA) between the sun-exposed peel and the shaded peel, suggesting that the response of the key enzymes to light exposure is well coordinated. Chlorophyll fluorescence quenching analysis showed that the sun-exposed peel had higher PSII quantum efficiency than the shaded peel at each given PFD, which resulted mainly from the higher photochemical quenching coefficient (qP). The sun-exposed peel had higher thermal dissipation capacity, as indicated by larger NPQ and Fo quenching, than the shaded peel at high PFD. In conclusion, the sun-exposed peel of apple fruit has higher activities of the Calvin cycle enzymes and higher rate of electron transport, leading to higher photosynthetic O2 evolution capacity. It appears that the acclimation of the Calvin cycle activities, thermal dissipation, and electron transport in apple peel are well coordinated in response to light exposure.

Effects of heat stress on gas exchange and photosystem II (PSII) photochemical activity of Phillyrea angustifolia exposed to elevated CO2 and subsaturating irradiance

Botany ◽  
2008 ◽  
Vol 86 (4) ◽  
pp. 435-441 ◽  
Author(s):  
Luca Vitale ◽  
Carmen Arena ◽  
Amalia Virzo De Santo ◽  
Nicola D’Ambrosio
Keyword(s):  
Heat Stress ◽  
Electron Transport ◽  
Gas Exchange ◽  
Photosystem Ii ◽  
Photochemical Efficiency ◽  
Calvin Cycle ◽  
Fluorescence Measurements ◽  
Significant Difference ◽  
Psii Photochemical Efficiency ◽  
Phillyrea Angustifolia

Gas exchange and chlorophyll a fluorescence measurements were performed simultaneously on leaves of Phillyrea angustifolia L. to assess the effects of heat stress (30 min at 40 °C) on photosynthesis and photosystem II (PSII) photochemical efficiency of plants grown at ambient CO2 and exposed to an elevated CO2 concentration (800 µmol·mol–1) and 300 µmol photons·m–2·s–1. No significant difference was found in the heat-induced decreases of net photosynthesis (PN), quantum yield of PSII electron transport (ΦPSII), and maximum PSII photochemical efficiency (Fv/Fm) between plants exposed to ambient and elevated CO2 concentrations, showing that elevated CO2 was not able to reduce the potential for photoinhibition at high temperatures under moderate light conditions. The heat-induced decrease of PN was higher than that of ΦPSII indicating that reductive power was more utilized in non-assimilatory processes than in CO2 fixation at both CO2 treatments. This result suggested that impairment of the Calvin cycle rather than electron transport inhibition was the main cause of the limitation in CO2 fixation.

Seasonal changes in chlorophyll fluorescence quenching and the induction and capacity of the photoprotective xanthophyll cycle in Lobaria pulmonaria

2002 ◽  
Vol 80 (3) ◽  
pp. 255-261 ◽  
Author(s):  
Tyler DB MacKenzie ◽  
Marianna Król ◽  
Norman PA Huner ◽  
Douglas A Campbell
Keyword(s):  
Chlorophyll Fluorescence ◽  
Electron Transport ◽  
Xanthophyll Cycle ◽  
Deciduous Forest ◽  
Light Exposure ◽  
Nonphotochemical Quenching ◽  
Pool Size ◽  
Lobaria Pulmonaria ◽  
Closed Canopy ◽  
Temperate Deciduous

Lobaria pulmonaria (L.) Hoffm. survives large changes in ambient light and temperature between winter and summer in temperate deciduous forests. Potential photosystem II (PSII) electron transport, measured at 20°C using chlorophyll fluorescence analysis, was consistent in thallus samples taken in March and August from a temperate deciduous forest, while the potential for nonphotochemical quenching (NPQ) was higher in March than in August. NPQ was, however, similar in March and August in a population from a coniferous site with a permanently closed canopy. Thalli measured at a typical March field temperature showed a depression of PSII electron transport, qp and gross CO2 uptake and a rise in realized NPQ. Xanthophyll cycle pigments were more abundant in the March than in the August samples in the deciduous forest populations but did not change significantly in the permanently closed-canopy population. In August, relatively low NPQ correlated with xanthophyll pool size in the deciduous forest samples. The more intense NPQ derived from low temperature and low CO2-electron demand in the March samples, however, was not correlated with xanthophyll pool size. Thus, most of the NPQ observed in the high light exposure March samples was not explained by variation in xanthophyll pool size.Key words: carotenoids, excitation quenching, lichen, nonphotochemical quenching, PSII electron transport.

scholarly journals Differences in the photosynthetic and physiological responses of Leymus chinensis to different levels of grazing intensity

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Min Liu ◽  
Jirui Gong ◽  
Bo Yang ◽  
Yong Ding ◽  
Zihe Zhang ◽  
...  
Keyword(s):  
Electron Transport ◽  
Photosynthetic Capacity ◽  
Photosynthetic Apparatus ◽  
Chloroplast Ultrastructure ◽  
Grazing Intensity ◽  
Photosynthetic Electron Transport ◽  
Thermal Dissipation ◽  
Leymus Chinensis ◽  
Heavy Grazing ◽  
Grazing Intensities

Abstract Background Grazing is an important land use in northern China. In general, different grazing intensities had a different impact on the morphological and physiological traits of plants, and especially their photosynthetic capacity. We investigated the responses of Leymus chinensis to light, medium, and heavy grazing intensities in comparison with a grazing exclusion control. Results With light grazing, L. chinensis showed decreased photosynthetic capacity. The low chlorophyll and carotenoid contents constrained light energy transformation and dissipation, and Rubisco activity was also low, restricting the carboxylation efficiency. In addition, the damaged photosynthetic apparatus accumulated reactive oxygen species (ROS). With medium grazing, more energy was used for thermal dissipation, with high carotene content and high non-photochemical quenching, whereas photosynthetic electron transport was lowest. Significantly decreased photosynthesis decreased leaf C contents. Plants decreased the risk caused by ROS through increased energy dissipation. With high grazing intensity, plants changed their strategy to improve survival through photosynthetic compensation. More energy was allocated to photosynthetic electron transport. Though heavy grazing damaged the chloroplast ultrastructure, adjustment of internal mechanisms increased compensatory photosynthesis, and an increased tiller number facilitated regrowth after grazing. Conclusions Overall, the plants adopted different strategies by adjusting their metabolism and growth in response to their changing environment.

Thylakoid Membrane Organisation in Sun/Shade Acclimation

1988 ◽  
Vol 15 (2) ◽  
pp. 11 ◽  
Author(s):  
JM Anderson ◽  
WS Chow ◽  
DJ Goodchild
Keyword(s):  
Electron Transport ◽  
Atp Synthase ◽  
Thylakoid Membrane ◽  
Photosynthetic Capacity ◽  
Photosynthetic Apparatus ◽  
The Sun ◽  
Shade Acclimation ◽  
Light Quantity ◽  
And Function ◽  
Changing Light

The photosynthetic apparatus of plants responds to changing light quantity and quality with coordinated changes in both the light-harvesting antennae of the photosystems and the amounts of electron transport components and ATP synthase. These compositional modulations are accompanied by changes in thylakoid membrane organisation and photosynthetic capacity. It is now clear that there is a dynamic continuum of organisation and function of the photosynthetic apparatus from the appressed granal and non-appressed stroma thylakoids within a chloroplast, to different chloroplasts within a leaf, to leaves within and between species. While it is very unlikely that there is a unique solution to photosynthesis in the sun or shade, substantial changes in composition, and hence thylakoid membrane organisation and function, are elicited as part of sun/shade responses.

scholarly journals Growth and physiological state of beech seedlings grown in a nursery in different light conditions

2010 ◽  
Vol 56 (No. 10) ◽  
pp. 442-450
Author(s):  
A. Jurásek ◽  
J. Leugner ◽  
J. Martincová
Keyword(s):  
Chlorophyll Fluorescence ◽  
Electron Transport ◽  
Electron Transport Rate ◽  
Physiological State ◽  
European Beech ◽  
Photosynthetic Electron Transport ◽  
Transport Rate ◽  
The Sun ◽  
Altitudinal Zone ◽  
Number Of Leaves

Seedlings of European beech of two populations (from the 4<sup>th</sup> and 7<sup>th</sup> forest altitudinal zone) were grown in a shaded and unshaded plastic greenhouse. The objective was to compare seedling growth and the function of assimilatory organs and to determine their reactions after transfer to different light conditions.Seedlings grown in the unshaded plastic greenhouse (the sun variant) were taller and stronger at the end of the first growing season and had the higher weight and volume of shoots and root systems than seedlings grown in the shade. A higher number of leaves, larger total leaf area and higher dry matter of leaves per 1 plant were determined in seedlings grown in the sun. The average area of one leaf was larger in seedlings grown in the shade. The higher photosynthetic electron transport rate (ETR) determined from the light curves of chlorophyll fluorescence in seedlings grown in the sun was apparently connected with the higher photosynthetic rate and more intensive growth of these seedlings. The transfer of seedlings from full sun to shade resulted only in small changes in chlorophyll fluorescence (Fv/Fm, ETR). On the contrary, the transfer of seedlings from the shaded plastic greenhouse to the sun induced photoinhibition leading to a significant reduction in the maximum quantum yield of photochemistry Fv/Fm and in the photosynthetic electron transport rate (ETR).  

scholarly journals Photosynthesis, Chlorophyll Fluorescence, and Carbohydrate Content of Illicium Taxa Grown under Varied Irradiance

2004 ◽  
Vol 129 (1) ◽  
pp. 46-53 ◽  
Author(s):  
Jason J. Griffin ◽  
Thomas G. Ranney ◽  
D. Mason Pharr
Keyword(s):  
Chlorophyll Fluorescence ◽  
Carbon Fixation ◽  
Photosynthetic Capacity ◽  
Light Exposure ◽  
Photochemical Efficiency ◽  
Free Radical Scavenger ◽  
High Light ◽  
Solar Irradiation ◽  
Radical Scavenger ◽  
Spad Readings

Tolerance to high solar irradiation is an important aspect of stress tolerance for landscape plants, particularly for species native to understory conditions. The objective of this study was to evaluate differential tolerance to high solar irradiation and underlying photosynthetic characteristics of diverse taxa of Illicium L. grown under full sun or 50% shade. Eleven commercially available taxa of Illicium were evaluated for light tolerance by measuring light-saturated photosynthetic capacity (Amax), dark-adapted quantum efficiency of photosystem II (Fv/Fm), and relative chlorophyll content using a SPAD chlorophyll meter. Comparisons of Amax indicated that three of the 11 taxa (I. anisatum L., I. parviflorum Michx. ex Vent., and I. parviflorum `Forest Green') maintained similar rates of light-saturated carbon assimilation when grown in either shade or full sun. All other taxa experienced a significant reduction in Amax when grown in full sun. Chlorophyll fluorescence analysis demonstrated that Fv/Fm was similar between sun and shade plants for the same three taxa that were able to maintain Amax. These taxa appeared to experience less photoinhibition than the others and maintained greater maximum photochemical efficiency of absorbed light. SPAD readings were not significantly reduced in these three taxa either, whereas most other taxa experienced a significant reduction. In fact, SPAD readings were significantly higher in I. parviflorum `Forest Green' when grown under full sun, which also maintained the highest Amax of all the taxa. These results suggest that there is considerable variation in light tolerance among these taxa, with I. parviflorum `Forest Green' demonstrating superior tolerance to high light among the plants compared. A more rigorous examination of I. parviflorum `Forest Green' (high light tolerance) and I. floridanum Ellis (low-light tolerance) demonstrated that I. parviflorum `Forest Green' had a considerably higher Amax, a higher light saturation point, greater potential photosynthetic capacity, reduced susceptibility to photoinhibition as indicated by superior PSII efficiency following light exposure, greater capacity for thermal de-excitation as indicated by a higher rate of nonphotochemical quenching (NPQ) under full sun, greater apparent electron transport rate (ETR) at mid-day, and higher concentrations of the free-radical scavenger myo-inositol. All of these factors contribute potentially to a greater capacity to use light energy for carbon fixation while minimizing photodamage.

scholarly journals Nitrogen Supply Affects Grain Yield by Regulating Antioxidant Enzyme Activity and Photosynthetic Capacity of Maize Plant in the Loess Plateau

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1094
Author(s):  
Kai Yue ◽  
Lingling Li ◽  
Junhong Xie ◽  
Setor Kwami Fudjoe ◽  
Renzhi Zhang ◽  
...  
Keyword(s):  
Grain Yield ◽  
Antioxidant Enzyme ◽  
Loess Plateau ◽  
Photosynthetic Capacity ◽  
Growth And Yield ◽  
Dry Matter Accumulation ◽  
The Loess Plateau ◽  
Area Index ◽  
Leaf Stage ◽  
Significant Difference

Nitrogen (N) is the most limiting nutrient for maize, and appropriate N fertilization can promote maize growth and yield. The effect of N fertilizer rates and timings on morphology, antioxidant enzymes, and grain yield of maize (Zea mays L.) in the Loess Plateau of China was evaluated. The four N levels, i.e., 0 (N0), 100 (N1), 200 (N2), and 300 (N3) kg ha−1, were applied at two timings (T1, one-third N at sowing and two-thirds at the six-leaf stage of maize; T2, one-third applied at sowing, six-leaf stage, and eleven-leaf stage of maize). The results show that N2 and N3 significantly increased the plant height, stem and leaf dry weight, and leaf area index of maize compared with a non-N-fertilized control (N0). The net photosynthetic rate, transpiration rate, stomatal conductance, and leaf chlorophyll contents were lower, while the intercellular carbon dioxide concentration was higher for non-fertilized plants compared to fertilized plants. The activities of peroxidase (POD) and superoxide dismutase (SOD) increased with N rate, but the difference between 200 and 300 kg ha−1 was not significant; further, the isozyme bands of POD and SOD also changed with their activities. Compared with a non-N-fertilized control, N2 and N3 significantly increased grain yield by 2.76- and 3.11-fold in 2018, 2.74- and 2.80-fold in 2019, and 2.71- and 2.89-fold in 2020, and there was no significant difference between N2 and N3. N application timing only affected yield in 2018. In conclusion, 200 kg N ha−1 application increased yield through optimizing the antioxidant enzyme system, increasing photosynthetic capacity, and promoting dry matter accumulation. Further research is necessary to evaluate the response of more cultivars under more seasons to validate the results obtained.

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