Understanding impact of heat, drought, and salinity stresses on growth and physiological attributes of Chenopodium album under field conditions

Utilizing potential of wild crop relatives becomes a necessity under current climate trends scenario. Chenopodium album is a natural inhabitant of Qatari harsh environment that is characterised by a combination of various stresses. This work investigated morphological, agronomical, and physiological responses of C. album to combination of abiotic stresses (heat, drought, and salinity) under field conditions. Field was divided into shaded and non-shaded plots, and three salinity levels were applied: 0 (control), 100 and 300 mM NaCl. Drought was imposed after 1 month of salinity application by withholding watering on half of the field area. Non-destructive measurements were taken in situ fortnightly, followed by analysis of the plant biomass and leaf elemental content at the end of experiment. It was found that C. album performed better when irrigated with 100 mM salt concentration; these plants also had highest water content and possessed highest drought tolerance. Also, despite accumulating significant quantities of Na and Cl ions in their leaves, physiological parameters were either enhanced (chlorophyll content) or not affected (stomatal conductance and photochemical efficiency of PSII) after 1 month of 100 mM salinity treatment. However, when abiotic pressures are combined and prolonged, C. album plants were similarly stressed, and statistical variations were no more detectable. Shading plants reduced negative impact of salinity and drought stresses. It is concluded that combined stresses have noticeable negative impact on C. album, yet alleviating heat and drought stresses by shade have improved plant tolerance to salinity.