Iron deficiency responses were investigated in roots of soybean, a Strategy I plant species. Soybean responds to iron deficiency by decreasing growth, both at the root and shoot level. Chlorotic symptoms in younger leaves were evident after a few days of iron deficiency, with chlorophyll content being dramatically decreased. Moreover, several important differences were found as compared with other species belonging to the same Strategy I. The main differences are (i) a lower capacity to acidify the hydroponic culture medium, that was also reflected by a lower H(+)-ATPase activity as determined in a plasma membrane-enriched fraction isolated from the roots; (ii) a drastically reduced activity of the phosphoenolpyruvate carboxylase enzyme; (iii) a decrease in both cytosolic and vacuolar pHs; (iv) an increase in the vacuolar phosphate concentration, and (v) an increased exudation of organic carbon, particularly citrate, phenolics, and amino acids. Apparently, in soybean roots, some of the responses to iron deficiency, such as the acidification of the rhizosphere and other related processes, do not occur or occur only at a lower degree. These results suggest that the biochemical mechanisms induced by this nutritional disorder are differently regulated in this plant. A possible role of inorganic phosphate in the balance of intracellular pHs is also discussed.

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BACKGROUND: The quality of melon fruit depends upon many factors that can be affected by growing conditions and post-harvest management. The aim of this work was to investigate the effect of nitrogen fertilisation levels on the fruit quality at harvest time and during storage. Experiments were performed in an open field using melon plants (Cucumis melo L. Var. Reticulatus cv. Prodigio). The nitrogen (N) was applied through fertigation using four fertilisation levels: 0, 55, 110 and 165 kg ha −1 . After harvest the fruits were stored at 10 • C for 8 days. At harvest time the yield, flesh firmness, skin and pulp colours, content of carotenoids, total phenols, ascorbic acid (AsA) and ethylene production were measured on fruits differently fertilised.

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The development of small unmanned aerial vehicles (UAVs) and advancements in sensors technology made consumer 17 digital cameras suitable for the remote sensing of vegetation. In this context, monitoring the in-field variability of maize 18 (Zea mays L.), characterized by high nitrogen fertilization rates, with a low-cost color-infrared airborne system could be 19 the basis for a site-specific nitrogen (N) fertilization support system. An experimental field with different N treatments 20 applied to silage maize was monitored during the years 2014 and 2015. Images of the field and reference destructive 21 measurements of above ground biomass (AGB), N concentration in AGB and N uptake were taken at V6 and V9 22 development stages. Classical normalized difference indices and the indices adjusted by crop ground cover were 23 calculated and regressed against the measured variables. Finally, image colorgrams were used to build PLS regression 24 models to explore the potential of band-related information in variable estimation. The best predictors were found to be 25 the ground cover and the adjusted GNDVI: regression equation at V9 resulted in R 2 of 0.7 and RRMSE<25% in 26 external validation. Colorgrams did not improve prediction performances due to the spectral limitations of the camera. 27 Therefore, the feasibility of the method should be tested in future research. In spite of limitations of sensor setup, the 28 modified camera was able to estimate maize AGB due to the very high spatial resolution. Since AGB is a robust proxy 29 of N status, the modified camera could be a promising tool for a low-cost N fertilization support system. 30

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