Luderlândio de Andrade Silva

Characterization of the double sulfites Cu2SO3·MSO3·2H2O (M = Cu, Fe, Mn or Cd) by photothermal techniques

Structural, thermal and optical properties as well as the non-radiative relaxation time τR and the characteristic diffusion time τβ of the synthesized double sulfites Cu2SO3 ·MSO3·2H2O (M = Cu, Fe, Mn or Cd) were investigated by photoacoustic spectroscopy. The positions of the bands for each compound were identified upon gaussian deconvolution and by Kramers–Kronig analysis, and the d–d and intervalence transitions were observed. The detection of two absorbing bands with low and high intensities is in agreement with previous results on reflectance for Cu2SO3CuSO3·2H2O. A slight shift is observed in the peak positions and in the measured thermal diffusivity, capacity and conductivity for different Ms and the thermal conductivity decreases with the ionic radius of the M(II) cations.

GAS EXCHANGE AND CHLOROPHYLL FLUORESCENCE OF CITRUS ROOTSTOCK VARIETIES UNDER SALT STRESS

High salt concentration in water are common in Brazilian semirad region, being important to research alternatives for use this waters on crop, like use of tolerant genotypes to salinity. Thus, in order to evaluate the saline stress perception of citrus rootstocks varieties crop from gas exchange and fluorescence analysis, an experiment was realized in greenhouse at the Center for Science and Technology Agrifood, CCTA, of Federal University of Campina Grande, UFCG, Pombal, PB, Brazil. It was studied in a randomized block design with factorial scheme (2x4), two salinity levels (0.3 and 4.0 dSm-1) and four varieties of citrus rootstocks [1 -common Sunki mandarin (TSKC), 2 - Florida Rough lemon (LRF), 3 -Santa Cruz Rangpur lime (LCRSTC) and 4-Volkamer lemon (LVK)], with three replications. The citrus rootstocks varieties grown on hydroponic system and at 90 days after sowing the plants were evaluated by gas exchange and PSII fluorescence at 0, 24 and 48 hours after application of treatments to determine the times for the physiological establishment of salt stress. The first 48h under saline conditions promoted changes in gas exchange and PSII fluorescence in varieties TSKC, LRF and LCRSTC indicating the begin of physiological stress; the common ‘Sunki’ mandarin and the ‘Florida Rough’ lemon are the more sensitive genotypes to saline stress, in order hand the ‘Santa Cruz Rangpur’ lime and ‘Volkamer’ lemon are the genotypes more tolerant.