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We examined the suitability of chlorophyll fluorescence-based indices to monitor and predict concentrations of fruit maturity compounds during tomato ripening under different growing conditions in the greenhouse. The aim of this study was to evaluate the effects of chlorophyll concentration changes on fluorescence-based indices and to exploit the relation between fluorescence and reflectance indices with the corresponding maturity compounds determined analytically.; Results: Fruits grown under water deficit matured faster than control fruits as recorded with fluorescence-based indices. The SFR_R index correlated well with the analytical determination of chlorophyll content, whereas the single-signal FRF_G correlated with lycopene content even if the sensor was unable to differentiate precisely between maturity stages 2 to 4. Neither the FLAV index nor the FLAV_UV index was suitable for flavonoid prediction in tomato fruits. Compared with fluorescence indices, the relation between the reflection index and pigment concentrations was lower for chlorophyll and higher for lycopene.; Conclusion: Chlorophyll and lycopene content in tomato fruits can be estimated by means of fluorescence indices during the pre-harvest phase. Since the chlorophyll decrease during tomato ripening is the driving force affecting all fluorescence signals, the methods are not reliable for estimation of other maturity compounds in tomato fruits. © 2018 Society of Chemical Industry.; © 2018 Society of Chemical Industry.

The document collates the practice abstracts developed by TOMRES from M1 to M21 and to be disseminated through internal and external platforms (EIP-Agri) during the project implementation.

Agricultural residues are natural sources for secondary metabolites as high value ingredients for industrial uses. The present work aims to exploit the accumulation potential of rutin and solanesol in tomato leaves following nitrogen and general mineral deficiency in a commercial-like greenhouse. Physiological responses of tomato plants were monitored non-destructively with a multiparametric fluorescence sensor, and biochemical parameters were determined by means of HPLC analysis. Nitrogen and general mineral limitation led to an accumulation of rutin in young tomato leaves while solanesol concentration was higher in mature leaves. In young leaves, the fluorescence indices SFR_R and NBI_G showed lower values compared to control plants for both stress treatments. On the contrary, FLAV and ANTH_RG values increased during the experiment, but no differences could be recorded in mature leaves. However, correlation analysis indicates, that the FLAV index is not a reliable tool to estimate the concentration of rutin and solanesol tomato leaves. To monitor fruit yield/quality as primary objective of tomato production, fruits showing symptoms of blossom end rot (BER) were counted before and after stress treatments. BER was determined more frequently for plants grown under a general mineral deficiency, concluding that a practical applicability at the end of fruit production is advisable. Our results indicate that by-products from Solanaceae plants are promising resources for valuable bioactive leaf compounds. To achieve the highest concentrations, the seasonal variation, the optimal environmental conditions, the concentrations in different plant organs and varieties as well as different production systems are of high interest for commercial implementation.

Highlight By employing magnetic resonance imaging to study below-ground sugar beet development, early changes in taproot growth and anatomy could be correlated with the first symptoms of Cercospora leaf spot disease., Cercospora leaf spot (CLS) infection can cause severe yield loss in sugar beet. Introduction of Cercospora-resistant varieties in breeding programmes is important for plant protection to reduce both fungicide applications and the risk of the development of fungal resistance. However, in vivo monitoring of the sugar-containing taproots at early stages of foliar symptoms and the characterization of the temporal development of disease progression has proven difficult. Non-invasive magnetic resonance imaging (MRI) measurements were conducted to quantify taproot development of genotypes with high (HS) and low (LS) levels of susceptibility after foliar Cercospora inoculation. Fourteen days post-inoculation (dpi) the ratio of infected leaf area was still low (~7%) in both the HS and LS genotypes. However, during this period, the volumetric growth of the taproot had already started to decrease. Additionally, inoculated plants showed a reduction of the increase in width of inner cambial rings while the width of outer rings increased slightly compared with non-inoculated plants. This response partly compensated for the reduced development of inner rings that had a vascular connection with Cercospora-inoculated leaves. Hence, alterations in taproot anatomical features such as volume and cambial ring development can be non-invasively detected already at 14 dpi, providing information on the early impact of the infection on whole-plant performance. All these findings show that MRI is a suitable tool to identify promising candidate parent lines with improved resistance to Cercospora, for example with comparatively lower taproot growth reduction at early stages of canopy infection, for future introduction into breeing programmes.

We examined the suitability of chlorophyll fluorescence-based indices to monitor and predict concentrations of fruit maturity compounds during tomato ripening under different growing conditions in the greenhouse. The aim of this study was to evaluate the effects of chlorophyll concentration changes on fluorescence-based indices and to exploit the relation between fluorescence and reflectance indices with the corresponding maturity compounds determined analytically.Fruits grown under water deficit matured faster than control fruits as recorded with fluorescence-based indices. The SFR_R index correlated well with the analytical determination of chlorophyll content, whereas the single-signal FRF_G correlated with lycopene content even if the sensor was unable to differentiate precisely between maturity stages 2 to 4. Neither the FLAV index nor the FLAV_UV index was suitable for flavonoid prediction in tomato fruits. Compared with fluorescence indices, the relation between the reflection index and pigment concentrations was lower for chlorophyll and higher for lycopene.Chlorophyll and lycopene content in tomato fruits can be estimated by means of fluorescence indices during the pre-harvest phase. Since the chlorophyll decrease during tomato ripening is the driving force affecting all fluorescence signals, the methods are not reliable for estimation of other maturity compounds in tomato fruits. © 2018 Society of Chemical Industry.