Photosynthetic performance and nutrient uptake under salt stress: Differential responses of wheat plants to contrasting phosphorus forms and rates

Abstract

Salt stress impacts phosphorus (P) bioavailability, mobility, and its uptake by plants. Since P is involved in many key processes in plants, salinity and P deficiency could significantly cause serious damage to photosynthesis, the most essential physiological process for the growth and development of all green plants. Different approaches have been proposed and adopted to minimize the harmful effects of their combined effect. Optimising phosphorus nutrition seems to bring positive results to improve photosynthetic efficiency and nutrient uptake. The present work posed the question if soluble fertilizers allow wheat plants to counter the adverse effect of salt stress. A pot experiment was performed using a Moroccan cultivar of durum wheat: Karim. This study focused on different growth and physiological responses of wheat plants grown under the combined effect of salinity and P-availability. Two Orthophosphates (Ortho-A & Ortho-B) and one polyphosphate (Poly-B) were applied at different P levels (0, 30 and 45 ppm). Plant growth was analysed on some physiological parameters (stomatal conductance (SC), chlorophyll content index (CCI), chlorophyll a fluorescence, shoot and root biomass, and mineral uptake). Fertilized wheat plants showed a significant increase in photosynthetic performance and nutrient uptake. Compared to salt-stressed and unfertilized plants (C+), CCI increased by 93%, 81% and 71% at 30 ppm of P in plants fertilized by Poly-B, Ortho-B and Ortho-A, respectively. The highest significant SC was obtained at 45 ppm using Ortho-B fertilizer with an increase of 232% followed by 217% and 157% for both Poly-B and Ortho-A, respectively. The Photosynthetic performance index (PItot) was also increased by 128.5%, 90.2% and 38.8% for Ortho-B, Ortho-A and Poly B, respectively. In addition, Poly-B showed a significant enhancement in roots and shoots biomass (49.4% and 156.8%, respectively) compared to C+. Fertilized and salt-stressed plants absorbed more phosphorus. The P content significantly increased mainly at 45 ppm of P. Positive correlations were found between phosphorus uptake, biomass, and photosynthetic yield. The increased photochemical activity could be due to a significant enhancement in light energy absorbed by the enhanced Chl antenna. The positive effect of adequate P fertilization under salt stress was therefore evident in durum wheat plants.

Selenium uptake, translocation, subcellular distribution and speciation in winter wheat in responses to phosphorus application combined with three kinds of selenium fertilizer

“…3). It suggested that medium P application had better effects on photosynthesis, which was consistent with the results of Loudari et al [47], who pointed out that adequate P signi cantly increased the photosynthetic parameter and biomass in wheat. There was a closely relationship between the photosynthesis in plants and Se fertilizers [32,44,48].…”

An insight into the different responses to salt stress in growth characteristics of two legume species during seedling growth

“…AGB slightly increased by reducing PH, while UGB remained relatively stable. Typically, UGB is less affected by salt stress, allowing more nutrients to be allocated to AGB, providing additional energy for stress resistance ( Loudari et al., 2022 ). However, in our study, the increase in salt concentration did not affect the PH of M. sativa , and the inhibiting effect of salinity on both aboveground and UGB was synchronized ( Figure 6 ).…”

Effect of Microbial Fertilizer on The Development of Pepper (Capsicum annuum L.) Seedlings Exposed to Salt Stress

“…In addition, the intake of nutrients is adversely affected. After the salt is taken by the plant, when it rises above a certain density, it destabilizes the membranes and breaks down organelles such as chloroplast (Loudari et al 2022). Therefore, the development of plants slows down or in case of prolonged exposure to salt, death may occur in plants (Altunlu 2020).…”