Physiological responses of the beet crop under agricultural environment and saline stress

Abstract

The deleterious effects of salts on plants exposed to high solar radiation tend to be more accelerated due to the increase of toxic ions in the aerial plant part. Consequently, the physiological and biochemical processes will be affected. These effects can be minimized, however, with the use of management strategies, such as the use of a shading screen and a protected environment. In this sense, the objective of this work was to evaluate the physiological responses of sugar beet cultivated in different environments and irrigated with saline water. The experiment was conducted in an experimental design entirely randomized, using the factorial scheme 3 × 2, equivalent to three environments (FS = full sun; SSOS = shading screen open on the sides and PE = protected environment) and two electrical conductivities of the irrigation water (0.5 and 6.2 dS m-1), with four repetitions. At 45 days after sowing (DAS) the following variables were analyzed: stomatal conductance, liquid photosynthesis, transpiration, internal CO2 concentration, leaf temperature, instantaneous water use efficiency, instantaneous carboxylation efficiency, intrinsic water use efficiency, and relative chlorophyll index. Irrigation with water of higher salinity negatively affected stomatal conductance, net photosynthesis, leaf temperature and instantaneous water use efficiency of sugar beet plants grown in a full sun environment. The protected environment and open shading on the sides partially mitigated the deleterious effects of salinity.
 Keywords: Beta vulgaris L., gas exchange, salinity levels.

Brackish Water, Phosphate Fertilization and Trichoderma in the Agronomic Performance of Beet Crops

“…These same authors found no mitigating effect on photosynthesis at 45 days after sowing. However, a similar trend for sugar beet was reported by [9], when using 100% phosphate fertilization in a saline environment.…”

“…Comparing phosphate fertilization in the presence of Trichoderma and water with a higher salinity (6.2 dS m −1 ), there was a statistical difference between the doses of 25% of the phosphorus recommendation and those of 50% and 100%, with the highest values of transpiration in the presence of the microorganism. When the concentration of salts in the soil rises, the osmotic potential decreases, causing the plants to strategically reduce the loss of water to the environment by reducing the leaf area, as the rate of transpiration is greater than absorption [9].…”

“…Salt stress favors a reduction in leaf area due to its deleterious effects. Therefore, with a reduced leaf area, there is a reduction in the photosynthesizing area and consequently in stomatal conductance; [9,39], evaluating the effect of salt stress on sugar beet crops, concluded that increasing the electrical conductivity of the water also reduced stomatal conductance.…”

“…In studies with beet irrigated with saline water, Ref. [3] concluded that increasing the concentration of salts in the irrigation water negatively affected the number of leaves, tuberous root length and productivity [9], as well as the physiological responses of the beet.…”

The impact of saline and water stress on the agronomic performance of beet crops

“…Under saline conditions, increasing water use efficiency is a strategy employed by moderately tolerant crops to mitigate high salt concentrations in the plant area (Fernandes et al, 2016;Oliveira et al, 2022). Likewise, Sousa et al (2022) also observed reductions in WUE with increasing irrigation water salinity under 50 and 100% ETc in zucchini crop.…”