Pesticide reduction: clustering organic croplands.

Organic and conventional farms often coexist, yet their proximity does not ensure compatibility. Larsen et al. reveal that being surrounded by organic fields reduces pesticide usage in organic fields but increases it in conventional fields. We discuss these findings, emphasizing the need to cluster organic croplands for reduced pesticide use.

Redox priming could be an appropriate technique to minimize drought-induced adversities in quinoa.

The exogenous use of the redox compound (H2O2) plays a significant role in abiotic stress tolerance. The present study investigated various H2O2 application methods (seed priming, foliar spray, and surface irrigation) with varying concentration levels (0 mM, 5 mM, 10 mM, 15 mM, 40 mM, 80 mM, and 160 mM) to evaluate the efficiency of supplying exogenous H2O2 to quinoa under water-deficit conditions. Drought stress reduced quinoa growth and yield by perturbing morphological traits, leading to the overproduction of reactive oxygen species and increased electrolyte leakage. Although all studied modes of H2O2 application improved quinoa performance, surface irrigation was found to be sensitive, causing oxidative damage in the present study. Seed priming showed a prominent increase in plant height due to profound emergence indexes compared to other modes under drought conditions. Strikingly, seed priming followed by foliar spray improved drought tolerance in quinoa and showed higher grain yield compared to surface irrigations. This increase in the yield performance of quinoa was attributed to improvements in total chlorophyll (37%), leaf relative water content (RWC; 20%), superoxide dismutase (SOD; 35%), peroxidase (97%), polyphenol oxidase (60%), and phenylalanine ammonia-lyase (58%) activities, and the accumulation of glycine betaine (96%), total soluble protein (TSP; 17%), proline contents (35%), and the highest reduction in leaf malondialdehyde contents (MDA; 36%) under drought stress. PCA analysis indicated that physio-biochemical traits (proline, SOD, TSP, total chlorophyll, MSI, and RWC) were strongly positively correlated with grain yield, and their contribution was much higher in redox priming than other application methods. In conclusion, exogenous H2O2 application, preferably redox priming, could be chosen to decrease drought-induced performance and yield losses in quinoa.

Salinity and exogenous H2 O2 improve gas exchange, osmoregulation, and antioxidant metabolism in quinoa under drought stress.

Climate change-induced concurrent drought and salinity stresses significantly threaten global crop yields, yet the physio-biochemical responses to combined stress in quinoa remain elusive. This study evaluated quinoa responses under four growth conditions: well-watered, drought stress, salt stress, and drought + salt stress with (15 mM) or without (0 mM) exogenous hydrogen peroxide (H2 O2 ) application. All examined stresses (alone or in combination) reduce quinoa growth and net photosynthesis, although salt stress was found to be less destructive than drought and combined stress. Strikingly, superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), stomatal conductance (gs ), photosynthetic rate (PN ), K+ uptake, shoot height, shoot fresh, and dry weight were increased by 46.1%, 22.2%, 101.6%, 12.9%, 12.1%, 22.4%, 7.1%, 14%, and 16.4%, respectively, under combined stress compared to drought alone. In addition, exogenous H2 O2 effectively improved gaseous exchange, osmolytes' accumulation, and antioxidant activity, resulting in reduced lipid peroxidation, which eventually led to higher plant growth under all coercive conditions. The principle component analysis (PCA) indicated a strong positive correlation between antioxidant enzymes and inorganic ions, which contributed efficiently to osmotic adjustment, particularly under conditions of salinity followed by combined stress. In short, in combination, salt stress has the potential to mitigate drought-induced injuries by promoting the absorption of inorganic solutes for osmoregulation in quinoa plants. Furthermore, exogenous application of H2 O2 could be opted to enhance quinoa performance to increase its tolerance mechanism against drought and salinity, even under combined stress.

Synergistic consequences of salinity and potassium deficiency in quinoa: Linking with stomatal patterning, ionic relations and oxidative metabolism.

Quinoa emerged as an ideal food security crop due to its exceptional nutritive profile and stress enduring potential and also deemed as model plant to study the salt-tolerance mechanisms. However to fill the research gaps of this imperative crop, the present work aimed to study the effect of potassium (K) deficiency either separately or in combination with salinity. First, we investigated the stomatal and physiological based variations in quinoa growth under salinity and K, then series of analytical tools were used with model approach to interpret the stomatal aperture (SA) and photosynthesis (Pn) changes. Results revealed that quinoa efficiently deployed antioxidants to scavenge the excessive reactive oxygen species (ROS), had high uptake and retention of K+, Ca2+, Mg2+ with Cl⁻ as charge balancing ion, increased stomata density (SD) and declined the SA to maintain the Pn which resulted the improved growth under salinity. Whereas, K-deficiency caused the stunted growth more severally under salinity due to disruption in ionic homeostasis, excessive ROS production elicited the oxidative damages, SD and SA reduced and ultimately declined in Pn. Our best fitted regression model explored that dependent variables like Pn and SA changed according to theirs signified explanatory variables with quantification per unit based as stomatal conductance (Gs, 51), SD (0.05), ROS (-0.79) and K+ (0.08), Cl⁻ (0.34) and Na+ (- 0.52) respectively. Overall, moderate salinity promoted the quinoa growth, while K-deficiency particularly with salinity reduced the quinoa performance by affecting stomatal and non-stomatal factors.

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

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-1 ) 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-1 ) 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+ , Mg2+ and Ca2+ concentration. It also enhanced the antioxidative system including ascorbic acid, phenylalanine ammonia-lyase, polyphenol oxidase and glutathione peroxidase, which scavenged the ROS (H2 O2 and O2 •- ) 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.

Differential response of quinoa genotypes to drought and foliage-applied H2O2 in relation to oxidative damage, osmotic adjustment and antioxidant capacity.

Quinoa (Chenopodium quinoa Willd.), a highly nutritious grain crop, is resistant to abiotic stresses (drought, salinity, and cold) and offers an alternate crop to endure harsh environmental conditions under the face of climate change. Naturally, quinoa genome displays a wide degree of variabilities in drought tolerance strategies. Therefore, the present study was designed to investigate drought tolerance variations and stress tolerance enhancement in four quinoa genotypes (Pichaman, Colorado-407D, IESP and 2-Want) thorough foliage-applied H2O2 with the purpose of identifying suitable genotype for water limited environments. The plants were exposed to two watering regimes (75% and 30% pot WHC) and foliage-applied H2O2 treatments (15 mM). The drought stress significantly reduced plant growth, relative water contents, chlorophyll and carotenoids contents and increased ROS production (H2O2 and O2•-) resulting in higher oxidative damage in all quinoa genotypes. Besides, drought stress significantly enhanced the antioxidants (SOD, PPO, and PAL) activity, total soluble sugars, proline, AsA contents and increased the total accumulation of measured inorganic ions in all quinoa genotypes. The PCA analysis indicated that parameters related to osmotic adjustment and antioxidant capacity were more pronounced in 2-Want and IESP genotypes, while parameters depicting oxidative damage were higher in Colorado-407D and more specifically in Pichaman. However, foliage-applied H2O2 effectively improved the osmolytes accumulation, antioxidants activity and K+/Na+ ratio which increased water relations, reduced lipid peroxidation and ultimately resulted in higher plant growth. Overall, 2-Want and IESP genotypes were found relatively more drought resistant, while exogenous application of H2O2 can be opted for more improvement in osmotic adjustment and antioxidant system, which may further enhance drought tolerance, even in sensitive genotypes of quinoa, such as Pichaman.