Paclobutrazol improves salt tolerance in quinoa: Beyond the stomatal and biochemical interventions

Abstract

Quinoa is gaining importance on global scale due to its excellent nutritious profile and environmental stress‐enduring potential. Its production decreases under high salt stress but can be improved with paclobutrazol application. This study showed involvement of some potential protective mechanisms in root and leaf tissues of quinoa plants treated with paclobutrazol (PBZ) against high salinity. The treatment levels were based on preliminary experiments, and it was found that salt stress (400 mm NaCl) markedly reduced growth and photosynthetic pigments while PBZ (20 mg/L) application significantly improved these attributes. Stomata density and aperture declined on adaxial and abaxial surfaces of leaves due to salinity. Paclobutrazol application significantly improved the stomatal density on both surfaces of leaves. Concentration of proline and soluble sugars increased in root and leaf tissues under salinity, which was more obvious in PBZ‐treated plants. Salinity stress induced the oxidative damage by increasing lipid peroxidation (MDA) level in roots and more specifically in leaf tissues. However, PBZ treatments ameliorated the drastic effects of salinity and markedly reduced oxidative damage in salt‐stressed quinoa plants. Enhanced activity of enzymatic antioxidants such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) was triggered by PBZ application, more pronounced in leaf than root tissues. Based on these findings, we conclude that PBZ application improves the salt tolerance in quinoa by activation of the above‐mentioned physiological and biochemical mechanisms specifically in leaves.

Nitrogen management enhanced plant growth, antioxidant ability, and grain yield of rice under salinity stress

“…One is enzymatic system, including SOD, POD, and CAT (Adolf, Jacobsen, & Shabala, 2013). The other one is nonenzymatic system, which produces some osmotic adjustment substances, for example proline, soluble sugar, and soluble protein (Iqbal et al., 2018; Waqas et al., 2017). These two systems play a vital role in detoxifying or scavenging ROS.…”

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

“…The PBZ application boosted the PAL activity, which may help to strengthen the primary and secondary metabolism and ROS scavenging action under salinity stress because of the vital role of PAL in these mechanisms (Miura and Tada ). There was also improved AsA, PPO, GPX contents in roots and leaves showing vigorous role of PBZ to improve oxidative defense system under salinity (Jaleel et al , Waqas et al ).…”

“…Four treatments were used as follows: (1) non‐saline irrigation (0 mM NaCl) without soil drenching of PBZ considered as control (Ct); (2) non‐saline irrigation (0 mM NaCl) with soil drenching of PBZ (20 mg l −1 ); (3) saline irrigation (400 mM NaCl) without soil drenching of PBZ; and (4) saline irrigation (400 mM NaCl) with soil drenching of PBZ (20 mg l −1 ). The PBZ concentration (20 mg l −1 ) was selected from our previous study (Waqas et al ), and the PBZ application was done at 0, 20, 40, 60 and 80 DAS. After seedlings establishment, at four to six full expanded leaves stage (33 DAS) mentioned as BBCH‐16 (Sosa‐Zuniga et al ), plants were irrigated with a saline solution of 400 mM NaCl and repeated with 10‐day interval until harvesting.…”

“…Quinoa also provides a highly nutritious food source that can be cultivated on marginal environments, which is not currently feasible for other major crops. Quinoa can achieve optimal growth and biomass between 100 and 200 mM (10, 20 dS m −1 ) of salinity (Jacobsen et al , Hariadi et al , Iqbal et al ), and 400 mM salinity causes significant reduction in growth and yield (Hariadi et al , Yang et al , Waqas et al , Yang et al ). However, the salt tolerance potential of quinoa greatly differs among genotypes (Schmockel et al ).…”

Yield potential and salt tolerance of quinoa on salt‐degraded soils of Pakistan

“…These ROS should be detoxified or scavenged to become safe from detrimental effects, that is, lipid peroxidation, protein denaturation, DNA damage, pigment break down and impairment in activities of various enzymes (Amjad, Akhtar, Yang, & Jacobsen, ). Two major antioxidant systems operate in plant cells to limit the excessive accumulation of ROS in cell, (a) enzymatic and (b) non‐enzymatic strategies (Adolf et al., ; Iqbal et al., ; Waqas et al., ). Both these systems were found operative in leaves of both tested quinoa genotypes (Figure ).…”