Gas Exchange, Stem Water Potential and Xylem Flux on Some Grapevine Cultivars Affected by Esca Disease

The effect of esca disease on gas exchange, stem water potential and xylem flux of adult grapevines of CabernetSauvignon, Sangiovese and Trebbiano cultivars was studied over three growing seasons. Water relations weremeasured at véraison and cluster ripening on three types of vines: i) healthy (control); ii) symptomatic and iii)apparently healthy in the year of measurements but that had showed esca symptoms in the previous season. Xylemflux was determined on cane segments by perfusion using a tracing dye before and after the appearance of escasymptoms. Esca induced a marked reduction (about 70%) in carbon assimilation and stomatal conductance,especially in Cabernet Sauvignon and Sangiovese. Esca did not affect the stem water potential. Gas exchangeparameters measured before the symptoms appeared in plants affected by esca were similar to those of healthyplants. Measurements made one month before the appearance of the symptoms cannot be used as screening methodto determine whether the vine will show esca. No differences in dye translocation were found before the symptoms’appearance. However, a decrease in xylem flux was measured in symptomatic vines of Cabernet Sauvignon. Afterthe appearance of esca symptoms, only the Trebbiano had a lower xylem flux than the healthy vines

Estimating biophysical and geometrical parameters of grapevine canopies ('Sangiovese') by an unmanned aerial vehicle (UAV) and VIS-NIR cameras

Three zones of different vine vigour were identified in a mature vineyard (Vitis vinifera 'Sangiovese') to test the potential of the Visible-Near Infrared (VIS-NIR) spectral information acquired from an unmanned aerial vehicles (UAV) in estimating the leaf area index (LAI), leaf chlorophyll, pruning weight, canopy height and canopy volume of grapevines. A significant linear correlation between the normalized differential vegetation index (NDVI) and LAI or between NDVI and leaf chlorophyll was found at day of the year (DOY) 162 and 190, whereas in August the relationship between NDVI and leaf chlorophyll was less evident. The canopy volume of low-vigour (LV) vines was 35 and 45 % of the high-vigour (HV) and medium-vigour (MV) ones, respectively. The pruning weight was linearly correlated with NDVI values of each vigour cohort. A good correlation between the measured canopy volume and UAV-estimated one as well as between measured and estimated canopy height was found. Our results indicated that the combined use of VIS-NIR cameras and UAV is a rapid and reliable technique to determine canopy structure and LAI of grapevine

How an ancient, salt-tolerant fruit crop, Ficus carica L., copes with salinity: a transcriptome analysis

Although Ficus carica L. (fig) is one of the most resistant fruit tree species to salinity, no comprehensive studies are currently available on its molecular responses to salinity. Here we report a transcriptome analysis of F. carica cv. Dottato exposed to 100 mM sodium chloride for 7 weeks, where RNA-seq analysis was performed on leaf samples at 24 and 48 days after the beginning of salinization; a genomederived fig transcriptome was used as a reference. At day 24, 224 transcripts were significantly upregulated and 585 were down-regulated, while at day 48, 409 genes were activated and 285 genes were repressed. Relatively small transcriptome changes were observed after 24 days of salt treatment, showing that fig plants initially tolerate salt stress. However, after an early down-regulation of some cell functions, major transcriptome changes were observed after 48 days of salinity. Seven weeks of 100 mM NaCl dramatically changed the repertoire of expressed genes, leading to activation or reactivation of many cell functions. We also identified salt-regulated genes, some of which had not been previously reported to be involved in plant salinity responses. These genes could be potential targets for the selection of favourable genotypes, through breeding or biotechnology, to improve salt tolerance in fig or other crops

Gas Exchange, Stem Water Potential and Xylem Flux on Some Grapevine Cultivars Affected by Esca Disease

The effect of esca disease on gas exchange, stem water potential and xylem flux of adult grapevines of Cabernet Sauvignon, Sangiovese and Trebbiano cultivars was studied over three growing seasons. Water relations were measured at veraison and cluster ripening on three types of vines: i) healthy (control); ii) symptomatic and iii) apparently healthy in the year of measurements but that had showed esca symptoms in the previous season. Xylem flux was determined on cane segments by perfusion using a tracing dye before and after the appearance of esca symptoms. Esca induced a marked reduction (about 70%) in carbon assimilation and stomatal conductance, especially in Cabernet Sauvignon and Sangiovese. Esca did not affect the stem water potential. Gas exchange parameters measured before the symptoms appeared in plants affected by esca were similar to those of healthy plants. Measurements made one month before the appearance of the symptoms cannot be used as screening method to determine whether the vine will show esca. No differences in dye translocation were found before the symptoms' appearance. However, a decrease in xylem flux was measured in symptomatic vines of Cabernet Sauvignon. After the appearance of esca symptoms, only the Trebbiano had a lower xylem flux than the healthy vines

Cultivar-specific transcriptome prediction and annotation in Ficus carica L.

The availability of transcriptomic data sequence is a key step for functional genomics studies. Recently, a repertoire of predicted genes of a Japanese cultivar of fig (Ficus carica L.) was released. Because of the great phenotypic variability that can be found in this species, we decided to study another fig genotype, the Italian cv. Dottato, in order to perform comparative studies between the two cultivars and extend the pan genome of this species. We isolated, sequenced and assembled fig genomic DNA from young fruits of cv. Dottato. Then, putative gene sequences were predicted and annotated. Finally, a comparison was performed between cvs. Dottato and Horaishi predicted transcriptomes. Our data provide a resource (available at the Sequence Read Archive database under SRP109082) to be used for functional genomics of fig, in order to fill the gap of knowledge still existing in this species concerning plant development, defense and adaptation to the environment

A regulated deficit irrigation strategy for hedgerow olive orchards with high plant density

Background & Aims There is not a consensus on the best irrigation approach for super-high density (SHD) olive orchards. Our aim was to design and test a regulated deficit irrigation (RDI) strategy for a sustainable balance between water saving, tree vigour and oil production. Methods We tested our RDI strategy for 3 years in an ‘Arbequina’ orchard with 1,667 trees ha−1. Two levels of irrigation reduction were applied, 60RDI and 30RDI, scaled to replacing 60 % and 30 %, respectively, of the of irrigation needs (IN). We also had a full irrigation (FI) treatment as control, with IN totalling 4,701 m3 ha−1 Results The 30RDI treatment showed the best balance between water saving, tree vigour and oil production. With a yearly irrigation amount (IA) of 1,366 m3 ha−1, which meant 72 % water saving as compared to FI, the reduction in oil yield was 26 % only. Conclusions Our results, together with recent knowledge on the effect of water stress on fruit development, allowed us to suggest a potentially improved RDI strategy for which a total IA of ca. 2,100 m3 ha−1 was calculated. Both some management details and the benefits of this suggested RDI strategy are still to be tested

The effect of NaCl stress and relief on gas exchange properties of two olive (Olea europaea) cultivars differing in tolerance to salinity

An alternative method to managing olive (Olea europaea L.) orchards for oil production is described. Using the coppiced system, the orchard is divided into 10 plots and all trees in one plot are coppiced year 1, all trees in a second plot are coppiced year 2, etc. In this way, the olive orchard consists of 10 different-aged plots after 10 years. Then a new cycle is started by coppicing trees in plot 1 in year 11, those in plot 2 in year 12, and so on. Since hardly any pruning is done after coppicing, the main advantages of this innovative management method are to reduce labor costs and the need for skillful labor, without negative effects on fruit yield, oil yield, or alternate bearing. Pesticide application, weed control, and fertilization were performed according to standard commercial practice. As a result, this system is more convenient than other training systems used for olive trees, it is suitable for renewing old trees, and can be adopted under many cultural conditions. The coppiced management system is compatible with soils of low fertility and is sustainable for long-term olive oil production