Co-application of soil superabsorbent polymer and foliar fulvic acid to increase tolerance to water deficit maize: photosynthesis, water parameters, and proline

Abstract

Fulvic acid (FA) and superabsorbent polymer (SAP) are widely applied to improve crop growth and yield under water deficit conditions, but little is known about the changes in crop physiological parameters related to water deficit tolerance when SAP and FA are combined. A pot test with maize (Zea mays L.) plants was conducted to examine the combined effect on photosynthesis, leaf water, proline, and growth under soil water deficit. Maize plants were subjected to two soil moisture conditions at the late crop growth phase: water deficit (WD, 50% field capacity) and well-watered (WW, 80% field capacity). The SAP (4.5 g m-2) was mixed into the soil layer at sowing and the FA solution (2 g L-1) was sprayed twice during water control. The combined application significantly improved maize grain yield under both watering conditions. The net photosynthesis rate, intrinsic quantum yield, fluorescent parameter (Fv/Fm), and chlorophyll content all improved with the combined application under both watering regimes. The compensating effect of combining chemicals on yield and photosynthesis parameters was higher than when applied alone under the two watering conditions. For prolonged and WD conditions, leaf proline and water content were higher under the combined treatment than when used separately. Under the WD conditions treated with FA and SAP, Fv/Fm had positive significant correlations with leaf water content and osmotic potential; leaf proline did not show any correlations with either the osmotic potential or leaf water content. This result demonstrated that SAP and FA could be combined to maintain high leaf proline and improve photosynthesis to mitigate adverse effects of moderate water storage on maize growth.

The Role of Antitranspirants in Mitigating Drought Stress in Plants of the Grass Family (Poaceae)—A Review

“…In a study conducted by Yang et al [80], a non-significant increase in yield was noted after FA application under drought conditions on maize. Nevertheless, the application of this substrate in combination with a superabsorbent polymer (SAP) significantly increased yield and the number of grains by 19.1% and 23.1%, respectively [81]. A similar result was obtained regarding water use efficiency at the grain yield level of maize under water deficit conditions.…”

Mixture Compound Fertilizer and Super Absorbent Polymer Application Significantly Promoted Growth and Increased Nutrient Levels in Pinus massoniana Seedlings and Soil in Seriously Eroded Degradation Region of Southern China

“…Under the same water conditions, SAP application can improve water uptake and retention and provide a better soil moisture environment for seedling growth and development, which improved the P n , T r , G s , and WUE ( Islam et al, 2011 ; Yang et al, 2017 ). In addition, the mixture compound fertilizer and SAP application effectively alleviated the adverse effects of mild drought on plant photosynthesis ( Zhao et al, 2013 ; Yang et al, 2019 ; Li et al, 2020 ), indicating that F2S improved the physiological characteristics of the seedlings compared with those with the other treatments. Under the same treatment, the P n , T r , and G s in July 2018 were higher than the values in July 2019 ( Table 2 ).…”

Effect of Different Soil Treatments with Hydrogel on the Performance of Drought-Sensitive and Tolerant Tree Species in a Semi-Arid Region

“…In both the SEN and TOL group, higher prolin concentration was recorded. From this point of view, no correlation with osmotic potential or RWC is surprising because the osmolytic properties of prolin usually explain higher water potential in hydrogel-treated plants [36]. In addition to the osmoprotective function, it acts as a metal chelator or antioxidant [37].…”