Differential Effect of Heat Stress on Drought and Salt Tolerance Potential of Quinoa Genotypes: A Physiological and Biochemical Investigation

Abstract

Soil salinity, drought, and increasing temperatures are serious environmental issues that drastically reduce crop productivity worldwide. Quinoa (Chenopodium quinoa Willd) is an important crop for food security under the changing climate. This study examined the physio-biochemical responses, plant growth, and grain yield of four quinoa genotypes (A7, Titicaca, Vikinga, and Puno) grown in pots containing normal (non-saline) or salt-affected soil exposed to drought and elevated-temperature treatments. Combinations of drought, salinity, and high-temperature stress decreased plant growth and yield more than the individual stresses. The combined drought, salinity, and heat stress treatment decreased the shoot biomass of A7, Puno, Titicaca, and Vikinga by 27, 36, 41, and 50%, respectively, compared to that of control plants. Similar trends were observed for grain yield, chlorophyll contents, and stomatal conductance. The combined application of these three stresses increased Na concentrations but decreased K concentrations in roots and shoots relative to control. Moreover, in the combined salinity, drought, and high-temperature treatment, A7, Puno, Titicaca, and Vikinga had 7.3-, 6.9-, 8-, and 12.6-fold higher hydrogen peroxide contents than control plants. All four quinoa genotypes increased antioxidant enzyme activities (CAT, SOD, and POD) to overcome oxidative stress. Despite A7 producing the highest biomass under stress, it did not translate into increased grain production. We conclude that Puno and Titicaca are more tolerant than Vikinga for cultivation in salt-affected soils prone to drought and heat stress.

Salinity and exogenous H2O2 improve gas exchange, osmoregulation, and antioxidant metabolism in quinoa under drought stress

“…However, plants grown under combined stress showed higher antioxidant enzymes' activity than plants grown under single drought and salinity (Figure 5). Recently, some studies reported that accumulation of osmolytes, (ROS)-scavenging enzymes, antioxidant system and phytohormones (ABA) production was more pronounced in combined stress conditions (i.e., drought and salinity) than in individual stress in different plants including quinoa (Abbas et al, 2023;dos Santos et al, 2022;Hussain et al, 2020Hussain et al, , 2023Zhang et al, 2017). In this study, a more strenuous antioxidant system might be plausible due to the efficient uptake of inorganic ions as osmotic adjustment (Table 4), which saves energy and eventually results in increased antioxidant (SOD, POD, and CA) activity under combined drought and salt stress (Figure 5).…”

“…Consequently, quinoa is one of the rare crop plants naturally adapted to tolerate abiotic stresses. Despite these amazing features, various works have shown that drought stress markedly reduced the performance of quinoa and its growth traits were inhibited under severe salt stress (Abbas et al, 2023;Waqas et al, 2019Waqas et al, , 2021. However, the deleterious impact of water-deficit and salinity stresses on crops' performance could be ameliorated by using plant growth regulators (PGRs), minerals, leaf extracts, and exogenous use of signaling molecules such as H 2 O 2 , NO, and H 2 S (Farooq et al, 2017;Hossain et al, 2015;Iqbal et al, 2018b;Savvides et al, 2016;Terzi et al, 2014).…”

“…In recent years, quinoa has become of increasing interest for research and market development as quinoa grain has a unique profile of vital amino acids (i.e., lysine, methionine and threonine) that are uncommon in cereals. Moreover, it is more resilient to various stresses such as drought (Iqbal et al, 2018a(Iqbal et al, , 2018b, salinity (Abbas et al, 2023;Iqbal et al, 2017;Waqas et al, 2019Waqas et al, , 2021, frost (Jacobsen et al, 2007), and even grow well under marginal land. Consequently, quinoa is one of the rare crop plants naturally adapted to tolerate abiotic stresses.…”

Worldwide development of agronomic management practices for quinoa cultivation: a systematic review

“…However, yields were lower in Pakistan, Syria, Uzbekistan and Vietnam ranging from 944 kg ha -1 to 2538 kg ha -1 . Drought, heat stress, and salt-affected soils in these regions may have negatively affected quinoa grain yield (Abbas et al, 2023).…”

Modelling Quinoa (Chenopodium quinoa Willd.) Seed Yield and Evapotranspiration under Water, Salt and Combined Water-Salt Stress

“…When the literature is analysed, it is understood that the tolerance of quinoa to salinity is relatively high, but it differs according to variety/genotype (Aloisi et al 2016;Carrasco et al 2017;Manaa et al 2019;Abbas et al 2022;Abbas et al 2023). Salinity refers to the presence of the major dissolved inorganic solutes, mainly Na + , Mg 2+ , Ca 2+ , K + , Cl -, SO4 2-, HCO3 -, and CO3 2-.…”