GROWTH AND PHOTOSYNTHETIC EFFICIENCY OF Atriplex nummularia UNDER DIFFERENT SOIL MOISTURE AND SALINE TAILINGS

Abstract

The disposal of the tailings (wastes) from desalinators is a growing problem, especially in semi-arid regions, and it is necessary to study halophytes such as Atriplex nummularia for the reuse of these saline waters. Thus, the objective of this study was to evaluate the effect of the interaction between levels of soil water content and salinity of irrigation water, gas exchange and growth of Atriplex nummularia Lindl. The plants were cultivated in vases with soils under two moisture levels (50 and 100% of the field capacity) and irrigated with saline waters from dilution of the desalinator waste, to obtain the following electrical conductivities (EC) of 0.39; 1.54; 2.15; 2.79; and 3.63 dS m-1. The experiment was conducted in a greenhouse for 160 days, with a triple factorial arrangement of 2x5x3, in a randomized complete block design with four replications. The photosynthetic, biometric and plant biomass parameters were evaluated. Irrigation with saline water reduced the net photosynthetic rate (A), stomatal conductance (gs), the effective quantum yield of photosystem II (ΔF/Fm’), photochemical quenching (qP) and the electron transport rate (ETR) of the plants for the two conditions of soil moisture. However, it did not impair the efficiencies of water use (WUE) and carboxylation (EIC) of plants. Plant growth rate and leaf biomass were stimulated under irrigation with saline water (EC ≤ 3.63 dS m-1), and when associated with soil moisture of 100% FC leaf biomass gains > 100% were obtained.

Physicochemical Quality of Fruits of West Indian Cherry Under Saline Water Irrigation and Phosphate Fertilization1

“…Reduction in fruit fresh mass may be a consequence of the reduction in the number and size of fruits. Additionally, excess salts in irrigation water requires greater energy effort for plants to absorb water and nutrients as a consequence of changes that occur in the osmotic potential of the soil solution, resulting in a decrease in photosynthetic rate, limiting plant production (OLIVEIRA et al, 2019). This situation promotes a reduction in fruit fresh mass as a result of physiological and biochemical changes to maintain cellular homeostasis.…”