Moringa Leaf Extract Mitigates the Adverse Impacts of Drought and Improves the Yield and Grain Quality of Rice through Enhanced Physiological, Biochemical, and Antioxidant Activities

Abstract

Agriculture, around the globe, is facing great challenges including the need to increase the production of nutrient-dense food and to withstand climate change’s impact on water and soil conservation. Among these challenges, drought stress is considered the most overwhelming danger for the agriculture sector. Organic plant growth ingredients are frequently used to enhance the growth and production of field crops cultivated in normal and unfavorable conditions. The present study was designed to explore whether leaves extracted from various landraces of Moringa could play a defensive role against drought stress in rice. Seedlings were grown under three water conditions, i.e., normal conditions (control; 100% field capacity), moderate (75%), and severe drought (50%). Leaf extracts obtained from four Moringa landraces were used as foliar spray at the tillering, panicle initiation, and grain filling stages of cultivating rice plants. The levels of water stress negatively influenced photosynthetic pigment synthesis, gas exchange traits, antioxidant activities, and yield and grain quality parameters. Leaf extracts, at the rate of 3%, from all the landraces significantly enhanced the biochemical, physiological, and yield-related attributes of rice plants under normal and unfavorable growth conditions. Particularly, leaf extract from the Faisalabad landrace was the most effective biostimulant to increase photosynthetic (8.2%) and transpiration (13.3%) rates, stomatal conductance (8.3%), chlorophyll a (15.9%) and b (9.7%) contents, and carotenoids (10.4%) as compared to water spray. The maximum photosynthesis rate was observed at 14.27 µmol CO2 m−2 s−1 via application of leaf extract from the Faisalabad landrace followed by the DG Khan (13.92 µmol CO2 m−2 s−1) and Multan (13.9 µmol CO2 m−2 s−1) landraces, respectively. Improved grain yield (25.4%) and grain quality (an increase of 10.1% in amylose with a decrease of 2.8% in amylopectin) in rice plants along with enzymatic activities such as catalase (21.2%), superoxide dismutase (38.6%), and ascorbate peroxidase (24.3%) were observed at the peak after application of leaf extract from the Faisalabad landrace. The maximum grain yield of 53.59 g per plant was recorded when using Faisalabad landrace leaf extract and the minimum (40 g) using water spray. It is concluded from the findings of the current experiment that leaf extract from the Faisalabad landrace possesses higher biostimulant potential than other landraces and can be applied to mitigate the adverse impacts of drought stress with higher productivity and improved grain quality of rice.

Combination of seed priming and nutrient foliar application improved physiological attributes, grain yield, and biofortification of rainfed wheat

“…Seed priming and foliar application of nutrients reduce ROS damage via elevating enzymatic and non-enzymatic antioxidant contents and strengthening drought resistance in plants (Farooq et al, 2021;Malik et al, 2021;Sattar et al, 2021). In plants, antioxidants play an essential role in enhancing plant tolerance to stress in response to abiotic stresses (Khan et al, 2023). According to our results, seed priming and foliar application positively affected antioxidant enzymes (POD and SOD) activity.…”

“…Foliar application of nutrients and seed priming preserve the plant and enhance growth by stimulating the synthesis of osmolytes and maintaining osmotic potential when water is scarce (Malik et al, 2021;Sattar et al, 2021;Saha et al, 2022). Various enzymatic antioxidants, such as SOD and POD, as well as non-enzymatic antioxidants, participate in ROS detoxification (Khan et al, 2023). Proline and GB are nonenzymatic antioxidants that protect the plant from negative effects by stabilizing reactive oxygen species (ROS; Malik et al, 2021;Malko et al, 2022).…”