Modification of sunlight radiation through colored photo-selective nets affects anthocyanin profile in Vaccinium spp. berries

<p>Objectives In recent years, the interest on the effects of the specific wavelengths of the light spectrum on growth and metabolism of plants has been increasing markedly. The present study covers the effect of modified sunlight conditions on the accumulation of anthocyanin pigments in two Vaccinium species: the European wild bilberry (V. myrtillus L.) and the cultivated highbush blueberry (V. corymbosum L.). <p>Methods The two Vaccinium species were grown in the same test field in the Alps of Trentino (Northern Italy) under modified light environment. The modification of sunlight radiation was carried out in field, through the use of colored photo-selective nets throughout the berry ripening during two consecutive growing seasons. The anthocyanin profile was then assessed in berries at ripeness. <p>Results The results indicated that the light responses of the two Vaccinium species studied were different. Although both studied species are shade-adapted plants, 90% shading of sunlight radiation was beneficial only for bilberry plants, which accumulated the highest content of anthocyanins in both seasons. The same condition, instead, was not favorable for blueberries, whose maturation was delayed for at least two weeks, and anthocyanin accumulation was significantly decreased compared to berries grown under sunlight conditions. Moreover, the growing season had strong influence on the anthocyanin accumulation in both species, in relation to temperature flow and sunlight spectra composition during the berry ripening period. <p>Conclusions Our results suggest that the use of colored photo-selective nets may be a complementary agricultural practice for cultivation of Vaccinium species. However, further studies are needed to analyze the effect of the light spectra modifications to other nutritional properties, and to elucidate the molecular mechanisms behind the detected differences between the two relative Vaccinium species

Effect of environmental, developmental and genetic factors on flavonoid and carotenoid profile of Vaccinium berries

Vaccinium berries contain high yields of antioxidant compounds, such as flavonoids and carotenoids, which are recognized to benefit human health. Therefore, commercial interest in cultivated and wild Vaccinium berries is increasing globally. Flavonoids and carotenoids are important secondary metabolites, the biosynthesis of which is regulated by interaction of the genetic background of the plant and the surrounding environment. In fruits the production of secondary metabolites has also a tight linkage with developmental processes. The present thesis is focused on developmental and environmental factors affecting the biosynthesis of carotenoids and flavonoids in berries of the genus Vaccinium. In bilberry altogether eight carotenoids were detected, with lutein and β-carotene being the most abundant compounds, accompanied by minor amounts of xanthophylls, such as antheraxanthin, neoxanthin, violaxanthin and zeaxanthin. During ripening the accumulation of carotenoids decreased. Simultaneously the expression of a carotenoid cleavage dioxygenase (VmCCD1) gene increased, indicating degradation of carotenoids during the fruit development. Simultaneously, flavonols and anthocyanins accumulated during the last stages of berry ripening. Environmental factors had a marked effect on the anthocyanin profile of ripe bilberries. Especially lower temperatures affected more on the accumulation of the delphinidin-based anthocyanidins than on the cyanidin-based ones. However, the spectral light composition also played a role, as an increased proportion in blue wavelengths increased the delphinidin-based anthocyanins at ripe stage. The effect of light quality on other phenolic compounds and carotenoid accumulation was less pronounced. The present results can be applied to cultivation of Vaccinium species in order to produce berries with high nutritional value

Anthocyanin Profile in Berries of Wild and Cultivated Vaccinium spp. along Altitudinal Gradients in the Alps

Vaccinium spp. berries provide some of the best natural sources of anthocyanins. In the wild bilberry (Vaccinium myrtillus L.), a clear increasing trend in anthocyanin biosynthesis has been reported toward northern latitudes of Europe, but studies related to altitude have given contradictory results. The present study focused on the anthocyanin composition in wild bilberries and highbush blueberry (Vaccinium corymbosum L. cv. Brigitta Blue) growing along altitudinal gradients in the Alps of northern Italy. Our results indicate an increasing accumulation of anthocyanins in bilberries along an altitudinal gradient of about 650 m. The accumulation was due to a significant increase in delphinidin and malvidin glycosides, whereas the accumulation of cyanidin and peonidin glycosides was not affected by altitude. Seasonal differences, especially temperature, had a major influence on the accumulation of anthocyanins in blueberries

円柱の回転振動による渦放出のアクティブ制御に関する研究

The present paper describes a new active method for controlling vortex shedding from a circular cylinder in a uniform flow, using rotary cylinder oscillations controlled by the reference velocity signal in the wake with some phase lag. The effectiveness of this active method is evaluated by measuring the response of mean and fluctuating velocities in the cylinder wake and by visualizing the flow field around the cylinder. It is found that velocity fluctuations are reduced by the control at the optimum phase lag, while they are enhanced at the reverse phase. The maximum reduction of 30 percent in the reference velocity fluctuations is obtained with the optimum control, where the optimum value of phase lag and the feedback coefficient are adopted. The modification of the mean velocity profile and the reduction in the fluctuating velocities in the wake are measured under the optimum control and the corresponding variations in the visualized flow field are recognized, similar to the change observed under the control with cross-flow cylinder oscillations

Temperature (a) and relative humidity (RH; b) measured under colored photo-selective nets.

<p>Data were recorded every hour continuously for one week during the fruit ripening. Temperature is expressed as difference between temperatures measured under net and under direct sunlight in open-field. </p

Daily temperatures measured during the ripening period of <i>Vaccinium</i> berries in two consecutive seasons (2013–2014).

<p>Colored bars show the ripening process, through green, pink and purple-blue (fully ripe) stages of bilberries in 2013 (a), in 2014 (c) and blueberries in 2013 (b), in 2014 (d).</p

List of anthocyanins (AC) identified in wild bilberries grown under different photo-selective nets during 2013 and 2014.

<p>The accumulation of the compound was significantly affected by the parameter, as indicated by two-way ANOVA test</p><p>*** p<0.001</p><p>** p<0.01</p><p>* p<0.05.</p><p>n.d. = not detected.</p><p>List of anthocyanins (AC) identified in wild bilberries grown under different photo-selective nets during 2013 and 2014.</p

Locations where bilberry plants where collected and later on cultivated in the test field.

<p>Blueberry bushes (cv. Brigitta Blue) were already grown in the test field.</p><p>Locations where bilberry plants where collected and later on cultivated in the test field.</p

Ratios of blue/red (B/R) components of visible light spectrum were measured during daytime under clear sky day (June 30, 2013).

<p>Ratios of blue/red (B/R) components of visible light spectrum were measured during daytime under clear sky day (June 30, 2013).</p