Soil drenching of paclobutrazol: An efficient way to improve quinoa performance under salinity

Abstract

Salinity extent and severity is rising because of poor management practices on agricultural lands, possibility lies to grow salt-tolerant crops with better management techniques. Therefore, a highly nutritive salt-tolerant crop quinoa with immense potential to contribute for future food security was selected for this investigation. Soil drenching of paclobutrazol (PBZ; 20 mg l ) was used to understand the ionic relations, gaseous exchange characteristics, oxidative defense system and yield under saline conditions (400 mM NaCl) including normal (0 mM NaCl) and no PBZ (0 mg l ) as controls. The results revealed that salinity stress reduced the growth and yield of quinoa through perturbing ionic homeostasis with the consequences of overproduction of reactive oxygen species (ROS), oxidative damages and reduced photosynthesis. PBZ improved the quinoa performance through regulation of ionic homeostasis by decreasing Na , Cl , while improving K , Mg and Ca concentration. It also enhanced the antioxidative system including ascorbic acid, phenylalanine ammonia-lyase, polyphenol oxidase and glutathione peroxidase, which scavenged the ROS (H O and O ) and lowered the oxidative damages (malondialdehyde level) under salinity in roots and more specifically in leaf tissues. The photosynthetic rate and stomatal conductance consequently improved (16 and 21%, respectively) in salt-stressed quinoa PBZ-treated compared to the non-treated ones and contributed to the improvement of panicle length (33%), 100-grain weight (8%) and grain yield (38%). Therefore, PBZ can be opted as a shotgun approach to improve quinoa performance and other crops under high saline conditions.

Physiological and biochemical markers for screening salt tolerant quinoa genotypes at early seedling stage

“…Under high salinity (300 or 500 mM NaCl), the performance of Q4 was strongly associated to the low level of both lipid peroxidation and oxidative stress. In addition, this genotype exhibited low photorespiration (low H 2 O 2 accumulation) and high APX activity even under high salinity ( Figure 7C, D), suggesting less cellular damage caused by oxygen radicals, as previously demonstrated by Waqas et al (2019).…”

“…Indeed, previous studies revealed that malondialdehyde (MDA) accumulation (a product of lipid peroxidation) should be considered as an indicator of oxidative stress and membrane integrity and could be used to discriminate between salt-tolerant and salt-sensitive genotypes (Demiral and Türkan 2005). To cope with oxidative stress, plants can regulate the ROS by scavenging them through an antioxidant defense system including enzymatic and non-enzymatic antioxidants (Gill and Tuteja 2010;Manaa et al 2014a;Waqas et al 2019).…”

Salicylic Acid and Calcium Signaling Induce Physiological and Phytochemical Changes to Improve Salinity Tolerance in Red Amaranth (Amaranthus tricolor L.)

“…Values with a common letter are not significantly different using LSD at the 5% level (Al-Whaibi et al 2012) as shown by the results for red amaranth in the present study. Exogenous application of signaling chemicals such as salicylic acid (SA) and calcium (Ca) have been found to reduce the deleterious effects of salinity (Rehman et al 2015;Waqas et al 2019) and improve plant adaptation to stressful environments (Dempsey et al 2011;Kudla et al 2018). Application of SA and/or Ca increased the total chlorophyll content and decreased EL in the present study-both of which are associated with the plant's ability to tolerate drought and excess salinity (Romero-Romero et al 2020).…”

“…Soil salinity affects growth and productivity in crop plants due to cellular damage caused by high Na + accumulation in plant tissues associated with ionic and osmotic stress (Munns and Tester 2008). However, under salt stress, plants accumulate reactive oxygen radicals (ROS), which at high concentrations can percolate into cell components and can damage proteins, DNA, chloroplasts, and mitochondria, disrupting their functioning as a result (Waqas et al 2019;Shabala et al 2012). Plants synthesize a defense system of non-enzymes to combat the ROSinduced oxidative stress (Shabala et al 2012).…”

Antioxidant activity of organic sulfides from fresh Allium macrostemon Bunge and their protective effects against oxidative stress in Caenorhabditis elegans

“…In the current study, the locomotion ability of C. elegans was hindered and its lifespan was significantly shortened under PQ-induced oxidative stress. However, group B organic sulfides could alleviate these effects and enhance the oxi- MDA level and ultimately improve the oxidative defense system (Waqas et al, 2017(Waqas et al, , 2019 as obvious in the present study (Figure 5b). In addition, organic sulfides can reduce cytotoxicity by clearing excess free radicals, suppress the body-movement hindrance, and alleviate the significant shortening of the lifespan due to excessive oxidation in C. elegans.…”