Alleviation of Copper-Induced Stress in Pea (Pisum sativum L.) through Foliar Application of Gibberellic Acid.

Copper (Cu) is an essential metal for plants. However, its excess in soil can adversely affect plant metabolism. The current study evaluated the effects of gibberellic acid (GA3) foliar applications on the performance of pea plants grown either in Cu-contaminated (Cu+) and non-contaminated (Cu-) soil. GA3 was sprayed (0, 10, 50, and 100 mg·L-1) on 15-days-old plants. The results showed that the increasing concentration of GA3 buffered the phytotoxic effects of Cu and enhanced plant growth, photosynthesis, and leaf chlorophyll content. Foliar-sprayed GA3 up to 100 mg·L-1 alleviated the oxidative stress, as inferred from the lower concentrations of MDA and H2O2 (33.3 µmol·g-1 and 182 µmol·g-1, respectively), and boosted the activity of superoxide dismutase (64.4 U·g-1·FW), peroxidase (122.7 U·g-1·FW), and catalase (226.3 U·g-1·FW). Interestingly, GA3 promoted Cu accumulation in different plant parts when compared to untreated plants, likely due to increased photosynthetic and transpiration rates. Overall, foliar application of GA3 promoted phytoextraction of Cu and alleviated the oxidative stress in pea plants grown in Cu+ soil.

Mineral Biofortification of Vegetables as a Tool to Improve Human Diet.

Vegetables represent pillars of good nutrition since they provide important phytochemicals such as fiber, vitamins, antioxidants, as well as minerals. Biofortification proposes a promising strategy to increase the content of specific compounds. As minerals have important functionalities in the human metabolism, the possibility of enriching fresh consumed products, such as many vegetables, adopting specific agronomic approaches, has been considered. This review discusses the most recent findings on agronomic biofortification of vegetables, aimed at increasing in the edible portions the content of important minerals, such as calcium (Ca), magnesium (Mg), iodine (I), zinc (Zn), selenium (Se), iron (Fe), copper (Cu), and silicon (Si). The focus was on selenium and iodine biofortification thus far, while for the other mineral elements, aspects related to vegetable typology, genotypes, chemical form, and application protocols are far from being well defined. Even if agronomic fortification is considered an easy to apply technique, the approach is complex considering several interactions occurring at crop level, as well as the bioavailability of different minerals for the consumer. Considering the latter, only few studies examined in a broad approach both the definition of biofortification protocols and the quantification of bioavailable fraction of the element.

Celery (Apium graveolens L.) Performances as Subjected to Different Sources of Protein Hydrolysates.

The vegetable production sector is currently fronting several issues mainly connected to the increasing demand of high quality food produced in accordance with sustainable horticultural technologies. The application of biostimulants, particularly protein hydrolysates (PHs), might be favorable to optimize water and mineral uptake and plant utilization and to increase both production performance and quality feature of vegetable crops. The present study was carried out on celery plants grown in a tunnel to appraise the influence of two PHs, a plant-derived PH (P-PH), obtained from soy extract and an animal PH (A-PH), derived from hydrolyzed animal epithelium (waste from bovine tanneries) on yield, yield components (head height, root collar diameter, and number of stalks), mineral composition, nutritional and functional features, as well as the economic profitability of PHs applications. Fresh weight in A-PH and P-PH treated plants was 8.3% and 38.2% higher, respectively than in untreated control plants. However, no significant difference was found between A-PH treated plants and control plants in terms of fresh weight. Head height significantly increased by 5.5% and 16.3% in A-PH and P-PH treated plants, respectively compared with untreated control (p ≤ 0.05). N content was inferior in PHs treated plants than in untreated control. Conversely, K and Mg content was higher in A-PH and P-PH treated plants as compared to the untreated ones. Furthermore, A-PH and P-PH improved ascorbic acid content by 8.2% and 8.7%, respectively compared with the non-treated control (p ≤ 0.001). Our results confirmed, also, that PHs application is an eco-friendly technique to improve total phenolic content in celery plants. In support of this, our findings revealed that animal or plants PH applications increased total phenolics by 36.9% and 20.8%, respectively compared with untreated plants (p ≤ 0.001).

Scion and Rootstock Differently Influence Growth, Yield and Quality Characteristics of Cherry Tomato.

Grafting is a valuable tool for managing problems of tomato soil-borne pathogens and pests, but often generates unpredictable effects on crop yield and product quality. To observe these rootstocks-induced changes, experimental designs including many rootstock-scion combinations are required. To this end, a greenhouse experiment was conducted on 63 graft combinations, involving seven cherry tomato scions grouped in large, medium and small-fruited, and eight rootstocks with different genetic backgrounds (crosses between Solanum lycopersicum and S. habrochaites or S. peruvianum or S. pimpinellifolium, plus an intraspecific hybrid), using ungrafted controls. The response of the graft partners was firstly analyzed individually using the environmental variance (σ2E), then by grouping them by classes. When analyzed individually, the scion genotype influenced fruit L*, b*, shape index, total soluble solids (TSS) and its ratio with tritatable acidity (TSS/TA), whereas plant growth and yield were unpredictable. After clustering the graft partners, some of these responses were attributable to the imposed classes. The S. habrochaites-derived hybrids maximized plant biomass, unlike the S. pimpinellifolium ones. Both classes reduced fruit biomass in small- and medium-fruited scions (by 11 and 14%, respectively). The S. habrochaites and S. peruvianum hybrids reduced a* and TSS, whereas promoted TA. L-ascorbic acid was reduced by grafting (from -23 to -45%), in the S. pimpinellifolium group too, indicating, even in low vigor rootstocks, a dilution effect worsening this nutraceutical trait of tomatoes.

Effects of Genotype, Storage Temperature and Time on Quality and Compositional Traits of Cherry Tomato.

The experiment addressed the effects of two storage temperatures, namely 10 (T10) and 20 °C (T20), on main quality and functional traits of three cherry tomato cultivars ('Eletta', 'Sugarland' and 'Ottymo'), after 0 (S0), 7 (S7) and 14 (S14) days of storage. At T10 both fruit weight and firmness were better retained during storage. At S14, T10 promoted fruit Chroma and overall fruit color deviation (ΔE*ab). Total polyphenols content (TPC) of fruits peaked at S7 (4660 mg GAE kg-1 DW) then declined at S14 (by 16%), with the highest values recorded at T10. Lycopene showed a similar trend, but with a higher average concentration recorded at T20 (488 mg kg-1 DW). ß-carotene content peaked at S14, irrespective of the storage temperature. At S14, the concentrations of phytoene and phytofluene were higher at T20 (48.3 and 40.9 mg kg-1 DW, respectively), but the opposite was found at S7. 'Sugarland' and 'Ottymo' showed the highest ΔE*ab along storage, with the former cultivar proving the highest TPC and lycopene content, whereas 'Eletta' did so for phytoene and phytofluene. Our results suggest that unravelling the possible functional interactions among these three carotenoids would allow for a better orientation of breeding programs, targeting the phytochemical evolution of tomatoes during refrigerated storage.