Water deficit and iron nutritional deficiency (iron chlorosis) are frequent environmental stresses affecting grapevine production in the Mediterranean region. The objectives of this work were (i) to study the combined effects of both stresses on aromatic profile of Tempranillo grapes, occurring simultaneously in the vineyard, and (ii) to evaluate the viability of foliar chlorophyll content at veraison (Chl) to early assess aromatic quality potential of grapes in those conditions. Twenty non-irrigated vineyard subzones (10 m × 10 m each), affected and non-affected by iron chlorosis, were monitored in Ribera del Duero Appellation of Origin (North-Central Spain) during two consecutive seasons. Factorial ANOVA was performed to study the effects of predawn leaf water potential and Chl measured at veraison on the must composition parameters and, specifically, on the concentrations of free and bound aromatic compounds. Water deficit tended to increase color intensity and extractable anthocyanin content of the grapes, whereas the incidence of iron deficiency enhanced total phenolic compound content within subzones with better water status. More water or iron stressed subzones restricted C 6alcohols contents than less stressed subzones. Without significant effects on vine vigor, yield or berry size, the incidence of iron chlorosis increased the concentrations of some specific terpenes, C 13-norisoprenoids, volatile acids and volatile phenols. These results showed that low to moderate iron stress can have positive effects on grape aromatic quality, and demonstrated that Chl can be a useful tool in precision viticulture to map the aromatic potential within rainfed vineyards affected by iron chlorosis.

Native trees species of the coastal zone of Campeche Mexico belonging to different families (Blood wood tree (Haematoxylum campechianum L.), White mangrove (Laguncularia racemosa (L.) Gaertn), Red mangrove (Rhizophora mangle L.), Button mangrove (Conocarpus erectus L.), Pink flower tree (Tabebuia rosea Bertol), Mahogany (Switenia macrophyla King) and Red cedar (Cedrela odorata L.)) were exposed to simulated acid rain for six weeks to assess visible foliar damage and effects on sulphur, nutrients, and photosynthetic pigment contents. A total of 245 seedlings were exposed four times a week from June to July under controlled conditions by using a simulated rainwater distribution system designed to reproduce rain events of 10 mm. Six treatments with five repetitions each were established at drought and irrigation conditions at different pH values. The results suggest that the water stress condition is related to the severity of the effects shown by individuals exposed to acid rain at pH values of 2.0 and 3.0. A significant increase in sulphur contents was observed on mature leaf tissues, being greater in the Mahogany, Red Cedar and Blood wood trees at pH 2 treatment under drought conditions. The chlorophyll a/b ratio showed a significant decrease in the Mahogany, White Mangrove and Blood wood trees, and nutrient levels were sensitive to the lowest pH values. According to the results, it could be observed that the Red mangrove, Button mangrove, Red cedar and Blood wood trees were more sensitive to acid rain. The Horsfall-Barratt method was applied to develop a severity scale; however, it is necessary to conduct a field survey for long-term exposure in parcels focused on sensible species to obtain a more precise scale.

Multiplex 330 (MX) is a portable, non-invasive fluorescence sensor that provides different multiparametric indices that are sensitive to the concentration of chlorophylls, flavonols, and anthocyanins on the leaf surface. This study investigated the use of these indices to assess the variability on free volatile composition of grapes (Vitis vinifera L.) in the field as well as other components of their quality potential in vineyards affected by iron deficiency chlorosis (IDC). Twenty non-irrigated Tempranillo/110 Richter vineyard subzones from non-affected to moderately affected by IDC were monitored in Ribera del Duero area (Spain) during two seasons. The results indicated that MX can characterize the spatial variation of leaf pigment concentrations, agronomic performance, and grape quality in vineyards affected by IDC. The MX indices measured at the leaf level close to harvest had better predictive values for the concentrations of free alcohols, volatile acids, C13-norisoprenoids, esters and acetates in the must than vine vigor, size or degree of technological maturity of the grapes. Our study demonstrates that the MX indices to estimate leaf pigment concentrations can be helpful to assess the technological maturity and free volatile composition of wine grapes in vineyards affected by IDC; nevertheless, the efficacy of the indexes may vary according to the year season.