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Made available in DSpace on 2020-12-10T19:57:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01. Added 1 bitstream(s) on 2021-07-15T14:37:17Z : No. of bitstreams: 1 S0006-87052020000100019.pdf: 279844 bytes, checksum: 2ed13e4de25bb6dbb70cf8a5e798c690 (MD5) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Seed germination and seedling growth are the stages most sensitive to salt stress, which can induceion-specific effects and oxidative stress. Although silicon (Si)has been known to improve plant defense systems against stressful-conditions, little is known about seed-priming with Si and mechanisms-of Si-mediated alleviation of salt stress in seedlings. To further the modulation of salt-stress responses and their relation with Si, seed priming with calcium silicate(0, 0.05 and 0.1mM Ca2SiO4) was used in lettuce seeds to improve seed germination and tolerance on subsequent salt-stress exposure (0 and 50 mM NaCl). The effect of Si-priming was assessed on germination, germination rate index and mean germination time and survival of seedlings in salt-stressful conditions supported by biochemical approach involving antioxidant responses. Overall results indicated that Si plays a role in alleviating the negative effects of salt stress by improving germination performance and displayed increased SOD, CAT and GR activities and reduced malondialdehyde and H2O2 contents. Thus,our findings demonstrate that seed-priming with Si is an efficient management technique that can be used to alleviate deleterious effects of salt-stressful on germination of lettuce seeds and enhance salt tolerance of seedlings due the increased activity of ROS-scavenging enzymes. Univ Estadual Paulista, Fac Ciencias Agr & Vet, Dept Biol Aplicada Agr, Jaboticabal, SP, Brazil Inst Nacl Semiarido, Nucleo Recursos Hidr, Campina Grande, Paraiba, Brazil Univ Fed Rural Semi Arido, Mossoro, RN, Brazil Univ Estadual Paulista, Fac Ciencias Agr & Vet, Dept Solos & Adubos, Jaboticabal, SP, Brazil Univ Estadual Paulista, Fac Ciencias Agr & Vet, Dept Biol Aplicada Agr, Jaboticabal, SP, Brazil Univ Estadual Paulista, Fac Ciencias Agr & Vet, Dept Solos & Adubos, Jaboticabal, SP, Brazil CNPq: 314380/2018-3 FAPESP: 2017/04787-6

This research aimed to evaluate the yield and quality of tomato plants under different managements of salt stress by adopting the partial root-zone saline irrigation (PRSI) system. The experiment was conducted in a greenhouse at the Universidade Federal Rural do SemiÁrido (UFERSA), Mossoró, Rio Grande do Norte (RN), Brazil. The experimental design was completely randomized, with six treatments and four replicates, totaling 24 plots. The treatments consisted of six different irrigation management regimes using low and high saline water (S1–0.5 and S2–5.0 dS·m−1), applied with or without PRSI, such that one side of the root-zone was submitted to saline water whilst the other side was water low salinity irrigated. For treatments T1 (control), T2 (S2 water), and T3 (alternate irrigation system between S1 and S2, with a cycling period of 15 d for each one), the PRSI was not applied; T4 (irrigation with S1 and S2, adopting the PRSI system from phase II to phase IV), T5 (irrigation with S1 and S2 in phase II, alternating in phase III; in phase III the inversion of the remaining water was made until the end of phase IV), and T6 (irrigation with S1 and S2, adopting the PRSI system in phase II, with the water switched between low and high saline water every 15 days, remaining until the end of phase IV) treatments were under the PRSI. The number of fruit per plant, fruit weight, fruit longitudinal and transverse diameter, pulp firmness, soluble solids content, titratable acidity, pH, vitamin C, color relation (a*/b*), lycopene, and β-carotene were determined as parameters for the fruit yield and quality evaluation. Our findings reinforce the importance of the use of PRSI systems followed by irrigation managements without loss of product quality, such as demonstrated by T4 and T5 water managements.

Although many questions concerning reactive oxygen species metabolism and cadmium (Cd) have not been answered, the rapid progress of proteomics and metabolomics, and their interactions, may be important tools in helping to define these roles more clearly in the near future. In addition, metabolomics can provide biochemical and physiological knowledge about network organizations in plants subjected to Cd stress. Understanding these processes may considerably increase our knowledge of Cd phytotoxicity and induced oxidative stress. Such information, complemented by using mutants, genetic engineering, and the development of cellular markers, will allow the manipulation of cellular redox status and identify traits for plant tolerance programs.