In vivo assessing flavonols in white grape berries (Vitis vinifera L. cv. Pinot Blanc) of different degrees of ripeness using chlorophyll fluorescence imaging

2007 ◽  
Vol 34 (12) ◽  
pp. 1092 ◽  
Author(s):  
Sándor Lenk ◽  
Claus Buschmann ◽  
Erhard E. Pfündel

Exposed and non-exposed halves of field-grown berries of the white grapevine Vitis vinifera L. cv. Pinot Blanc at various stages of ripeness were analysed using chlorophyll fluorescence imaging. The stage of ripeness was classified by the total sugar concentration which ranged between 120 and 300 g L–1 for the different berries but was similar in the exposed and the non-exposed half of individual berries. Fluorescence was excited in the UV-A and the blue spectral region and detected at red as well as far-red wavelengths. At both emission ranges, UV-excited fluorescence was weak and required correction for the contribution of small false signals. After correction, in vivo UV screening by berry skins was derived from the ratio of UV-A to blue-excited fluorescence intensities, and a relationship between in vivo UV screening and flavonol quantity was established: the quantity of flavonols was determined by spectral analysis of extracted phenolics. Significantly high flavonol concentrations, and effective in vivo UV screening, were detected in most exposed half-berries at sugar concentrations higher than 200 g L–1 but not in non-exposed samples. This suggests that radiation-exposure conditions determine flavonol synthesis. Based on the absence of flavonol accumulation in exposed half-berries with sugar concentrations smaller than 200 g L–1, however, it is suggested that berries need to arrive at an advanced stage of ripeness before responding to radiation-exposure by synthesising large amounts of UV-protecting flavonols. Chlorophyll degradation, which was followed by blue-excited intensities of far-red fluorescence, progressed in parallel with increasing sugar content suggesting that chlorophyll degradation is associated with berry ripening. In addition, exposure to sunlight appeared to slightly stimulate chlorophyll decay.

2009 ◽  
Vol 52 (2) ◽  
pp. 171-175 ◽  
Author(s):  
Min-Hyuk Oh ◽  
Dong Woo Kang ◽  
Tae Hoon Kim ◽  
Yong-Hwan Moon ◽  
Byoung Yong Moon ◽  
...  

1999 ◽  
Vol 26 (7) ◽  
pp. 717 ◽  
Author(s):  
Barry Osmond ◽  
Owen Schwartz ◽  
Brian Gunning

By analogy with the starch printing technique, it was hypothesised that photoinhibition could be used to print images on leaves that would be invisible to the eye, but easily revealed by chlorophyll fluorescence imaging. We first illustrate the process of chlorophyll fluorescence printing on leaves of the shade plant, Cissus rhombifolia, using photographs of artefacts from starch printing experiments in the laboratory of Molisch. We then use portraits of current leaders in chlorophyll fluorescence research to demonstrate the stability of these images in living tissues. Text printing from microfilm of Ewart’s pioneering studies in photoinhibition shows the resolution of the method with the fixed-focus, portable, imaging system used here. The stability of images, as well as quenching analysis of images and of leaves, suggests that localised photoinactivation, rather than sustained photoprotection, is responsible for the detail displayed by fluorescence printing. Electron micrograph positives of stained thylakoids can be printed to create an illusion of what is imagined to be the source of chlorophyll fluorescence at the membrane level. Individual chloroplasts in adjacent cells under the grid pattern of granal stacks printed on leaves were also examined using a confocal microscope. Compared with chloroplasts in the shaded parts of the grid, those in the photoinactivated parts of the grid show greatly reduced chlorophyll autofluorescence. Moreover, these chloroplasts have lost the localised bright fluorescence from grana. Comparisons of fluorescence yields show that relative chlorophyll autofluorescence from grana observed in the confocal microscope parallels that determined in leaves. Our experiments provide direct visual evidence that fluorescence from grana is lost following photoinactivation of photosystem II in vivo.


OENO One ◽  
2009 ◽  
Vol 43 (2) ◽  
pp. 83 ◽  
Author(s):  
Iñaki García de Cortázar-Atauri ◽  
Nadine Brisson ◽  
Nathalie Ollat ◽  
Olivier Jacquet ◽  
Jean-Christophe Payan

<p style="text-align: justify;"><strong>Aims</strong>: An analysis of the asynchrony and dynamics of dry matter accumulation and water content in the grape berries growth period (Vitis vinifera L.) was carried out on a macroscopic scale (berry population). Experimental studies suggest a framework to evaluate the asynchronous nature of grapevine maturation and to propose a simple model to simulate dry matter and water dynamics.</p><p style="text-align: justify;"><strong>Methods and results</strong>:Amethodology based on the measurement of the density of the berries was used, providing information on the dry matter, water content and distribution of the berry populations during the veraison - harvest period. The main experiment was carried out in Rhone valley vineyards on the«Grenache N » and « Syrah » varieties. Additional information was gathered in Burgundy vineyards on « Pinot noir » and « Chardonnay » varieties. A relationship between the sugar content (°Brix) and water content of a berry was observed, which was robust and identical for all varieties. The asynchronous nature of berry growth was confirmed and densimetry allows quantifying the homogeneity of harvest. A model was proposed to modelling dry matter growth, based on thermal time and final potential dry weight. A single relationship was obtained for the two varieties studied which seemed to be independent of field conditions (soil and year). To model water content dynamics (or °Brix, using the relationship obtained between them), two components were defined, one of which is related to the berry phenological stage and the other depends on the water status of the plant.</p><p style="text-align: justify;"><strong>Conclusion</strong>: The results provide a conceptual framework to better understand and represent the dynamics of dry matter accumulation and water content of a population of grape berries, and to evaluate the asynchronous nature of grapevine maturity.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: The models and relationships proposed could be used as a tool to better identify and understand key factors and processes occurring in the field until the detailed processes of berry growth are better understood and can be incorporated into the model. This model could be incorporated into a crop model of vine growth.</p>


2018 ◽  
Vol 99 (2) ◽  
pp. 915-922 ◽  
Author(s):  
Eirini A Panagopoulou ◽  
Antonia Chiou ◽  
Eirini K Nikolidaki ◽  
Margarita Christea ◽  
Vaios T Karathanos

2020 ◽  
Vol 20 (sup2) ◽  
pp. 812-826
Author(s):  
Mehdi Jahani ◽  
Mahdiyeh Beheshti ◽  
Mohammad Hossein Aminifard ◽  
Atefeh Hosseini

2017 ◽  
Vol 56 (35) ◽  
pp. 9762 ◽  
Author(s):  
Heng Wang ◽  
Xiangjie Qian ◽  
Lan Zhang ◽  
Sailong Xu ◽  
Haifeng Li ◽  
...  

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