Solar radiation affects grapevine susceptibility to Plasmopara Viticola

Marta, Anna Dalla; Stefano, V. Di; Cerović, Zoran G.; Agati, Giovanni; Orlandini, Simone

doi:10.1590/s0103-90162008000700011

Cited by 9 publications

(2 citation statements)

References 19 publications

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“…In our studies with okra, we have found no effect of a high nitrogen application (administered daily instead of weekly) on flavonoids independent of the UV treatments (data not shown). Higher flavonoid concentrations have also been found to be associated with improved defense against pathogens in some species (e.g., grapevine) (Agati et al, 2008;Dalla Marta et al, 2008), but this was addressed in our study. We did find, however, that leaf age and surface (abaxial vs. adaxial) were factors that affected UV-absorbing compound concentrations in the leaf.…”

Section: Discussionmentioning

confidence: 79%

Rapid adjustment in epidermal UV sunscreen: Comparison of optical measurement techniques and response to changing solar UV radiation conditions

Neugart

Tobler

Barnes

2021

Physiologia Plantarum

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The accumulation of soluble and cell-wall bound UV-absorbing compounds (i.e., flavonoids) in the epidermis and the mesophyll of leaves is a response of plants to UV exposure. These compounds are known to function in UV screening, but they are also of potential value for food quality. One way to non-destructively monitor UV screening in leaves is by optical methods, from which UVA-PAM and Dualex instruments stand out. The degree and rapidity to which plants can modulate UV screening in response to fluctuating solar UV conditions is poorly understood. In this study, okra plants were exposed to two solar radiation treatments (near-ambient UV [+UV] and attenuated UV [ÀUV]) and the epidermal UV transmittance (T UV ; UVA-PAM) and flavonoid index (Dualex) were measured in the youngest and second youngest mature leaves over three consecutive days and within an individual day. The day-to-day (measured near solar noon) and diurnal (over the course of a day) measurements of leaf optical properties indicated that T UV decreased and flavonoid index increased in the adaxial epidermis $50% until 15:00 CDT then returned close to morning values later in the day. Correlations between UV-B radiation and T UV and flavonoid index revealed highest values 30 min to 1 h prior to the measurements. These findings indicate that plants can respond quickly to fluctuating solar UV conditions and underlines the importance of the harvest-time point for health-promoting compounds in fruit and vegetables. Our findings also indicate that the UVA-PAM and the Dualex instruments are both suitable instruments to monitor rapid changes in UV screening in plants. | INTRODUCTIONUltraviolet radiation (UV; 280-400 nm, including the UV-B [280-315 nm] and UV-A [315-400 nm] wavebands) comprises a relatively small portion of the total solar radiant energy reaching the Earth's surface, but this radiation has the potential to induce a number of photomorphogenic and deleterious effects in plants. These effects include oxidative damage, changes in plant biochemistry, partial inhibition of photosynthesis, and growth reduction (Albert et al., 2011;Hideg et al., 2013;Jordan, 2002). However, plants possess a number of UV protective mechanisms that can mitigate much of the UV-induced damage under normal field conditions (Jansen et al., 1998). In particular, studies have highlighted the regulatory properties of low, ecologically relevant UV-B levels that can trigger structure-dependent accumulation of polyphenols (Neugart et al., 2012;Schreiner et al., 2012). The increase in polyphenols, such as flavonoids and hydroxycinnamic acids,

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Section: Discussionmentioning

confidence: 79%

Rapid adjustment in epidermal UV sunscreen: Comparison of optical measurement techniques and response to changing solar UV radiation conditions

Neugart

Tobler

Barnes

2021

Physiologia Plantarum

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“…Solar energy radiation is essential in plant physiology and pathophysiology hence its knowledge is fundamental for example, to estimate evapotranspiration (Gocić et al, 2015) (Petković et al, 2015) and to predict infection risk of some fungus diseases (Katsantonis et al, 2017) (Dalla Marta et al, 2008) that are needed to schedule irrigation and fungicide spraying. Solar energy radiation is usually expressed in terms of the energy flux density through a horizontal area (irradiance) and an integrated value over one day (daily solar insolation) fits these applications.…”

Section: Introductionmentioning

confidence: 99%

Solar energy radiation measurement with a low–power solar energy harvester

López-Lapeña

2018

Computers and Electronics in Agriculture

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Solar energy radiation measurements are essential in precision agriculture and forest monitoring and can be readily performed by attaching commercial pyranometers to autonomous sensor nodes. However this solution significantly increases power consumption up to tens of milliwatts and can cost hundreds of euros. Since many autonomous sensor nodes are supplied from photovoltaic (PV) panels which currents depend on solar irradiance, we propose to double PV panels as solar energy sensors. In this paper, the inherent operation of the low-power solar energy harvester of a sensor node is also used to measure the open circuit voltage and the current at the maximum power point (I MPP), which allows us to determine solar irradiance and compensate for its temperature drift. The power consumption and cost added to the original solar energy harvester are minimal. Experimental results show that the relation between the measured I MPP and solar irradiance is linear for radiation above 50 W/m 2 , and the relative uncertainty limit achieved for the slope is ±2.4% due the light spectra variation. The relative uncertainty limit of daily solar insolation is below ±3.6% and is hardly affected by the so called cosine error, i.e. the error caused by reflection and absorption of light in PV panel surface.

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