Photosynthetic performance in Eucalyptus clones cultivated in saline soil

Abstract

The aim of this study was to evaluate the photosynthetic performance of Eucalyptus clones with the aim of identifying their tolerance to soil saline stress conditions. The experiment was arranged in a randomized block design with a 3 × 4 factorial arrangement: in five replications, totaling 60 plots, three Eucalyptus clones were used, VC865, I224, and I144, which were exposed to four concentrations of NaCl (0, 1, 2 and 3 g NaCl kg-1 of soil). Clone I144 shows mechanisms of salinity tolerance as smaller reductions in the stomatal conductance, transpiration, photosynthesis, photochemical efficiency of PSII, photosynthetic pigment content and total dry mass. On the other hand, clone I224 presents greater physiological damage, indicating high susceptibility to salt stress, while VC865 shows moderate sensitivity to salinity. Variables related to photosynthetic performance, such as gas exchange, photochemical efficiency of PSII and photosynthetic pigments are potentially reliable physiological indicators for selecting of tolerant Eucalyptus clones to salt stress.