Journal of Agronomy and Crop Science最新文献

Timely assessment of panicle relative water content in wheat is critical for harvest diagnosis and precision management of wheat to generate higher yield and better quality. The objective of this study was to determine the most suitable index using wheat panicle hyperspectral data for the assessment of wheat panicle relative water content. Ground-based hyperspectral datasets were obtained during the heading-maturity growth stage under eastern and western Guanzhong wheat eco-sites in Shaanxi Province using the FieldSpec3 Pro spectrometer. This study systematically analysed the performance of three newly developed types of two-band hyperspectral spectral indexes and previously published spectral indexes to estimate wheat panicle relative water content. Results showed that the newly developed two-band index NDVI (R₁₈₉₀, R₂₁₃₄) in eastern Guanzhong wheat eco-sites and NDVI (R₁₂₂₅, R₁₃₀₂) in western Guanzhong wheat eco-sites performed best in estimating wheat panicle relative water content at the panicle scale in wheat, generating the coefficients of determination, root mean square error and residual prediction deviation values between the measured and predicted values of 0.98 and 0.98, 2.95% and 2.69%, 6.98 and 6.45, respectively. This study indicates that the relative water content of winter wheat panicles can be precisely estimated using panicle hyperspectral vegetation indexes, which aids in monitoring the wheat maturation phase.

Crop evapotranspiration (ET_c) is a critical component of crop growth, yield formation, and the water cycle, and its accurate estimation is essential for agricultural management decisions. However, uncertainties remain regarding the applicability of existing ET_c models under different climatic and planting conditions. In this study, the Penman-Monteith (PM) model coupled with the Katerji-Perrier (KP) and the Farias (FA) canopy resistance methods, the Priestley-Taylor (PT), the Shuttleworth-Wallace (SW), and the revised SW (R-SW) models were applied for ET_c calculation for rainfed maize in Harbin City, Heilongjiang Province (NE-H) from 2023 to 2024, and film-mulched maize in Ordos City, Inner Mongolia (NW-I) from 2020 to 2021. All model outputs were calibrated and validated using measured ET_c with the Bowen Ratio Energy Balance method. The PM-KP, R-SW, and PT models in NW-I and the PM-KP and PT models in NE-H performed better overall, with the coefficient of determination (R²) close to 0.8. The PT model achieved the highest simulation accuracy in NW-I, with an R² of 0.98, a mean absolute error (MAE) of 0.01 mm/h, and a root mean square error (RMSE) of 0.02 mm/h. In NE-H, the PM-KP model outperformed the other models, with an R² of 0.87, an MAE of 0.02 mm/h, and an RMSE of 0.08 mm/h. Additionally, model performance exhibited substantial variability across different regions and temporal scales. In NW-I, model errors responded strongly to vapour pressure deficit (VPD) and net radiation (R_n), with significant interactive effects with leaf area index (LAI). Whereas in NE-H, errors of most models showed no consistent variation trends along VPD and R_n gradients, except for the PM-FA model, with only specific models exhibiting systematic responses to extreme conditions. This study provides targeted technical support for water-efficient irrigation management under specific climates. Future research should enhance the integration of meteorological and crop physiological factors into ET_c model parameterisation and develop region-specific correction terms for canopy resistance and energy partitioning processes to improve model adaptability for broader agroclimatic contexts.

Seed priming is a widely used pre-sowing treatment to enhance plant resistance to drought stress. However, the effects of seed priming with polyethylene glycol on plant cuticle, which plays a crucial role in reducing water loss, remain unclear. In this study, we primed sweet sorghum (Sorghum bicolor (L.) Moench) seeds with PEG and subjected the seedlings to drought stress. PEG priming increased the accumulation of cuticular wax and cutin under drought conditions, resulting in reduced leaf water loss and improved leaf relative water content compared to non-primed seedlings. Transcriptome and hormone analyses revealed that PEG priming influenced the accumulation of ACC, JA-Ile, JA, ABA and SA under drought stress. Exogenous applications of ABA, JA and ABA/JA led to 6.1%, 19.7% and 23.1% increases in total wax coverage, respectively, on seedlings under non-stress conditions. We also identified MYB30, a transcription factor from sorghum, and transgenically overexpressed it in Arabidopsis. The MYB30-overexpression lines showed significantly increased wax accumulation and enhanced drought resistance compared to wild-type (WT) plants. These findings suggest that PEG priming modulates hormone levels, which regulate transcription factors such as MYB30, ultimately promoting the expression of genes involved in wax and cutin biosynthesis and improving drought tolerance.

This study assessed the DSSAT/CERES-Maize model's ability to simulate daily and cumulative ET, water productivity (WP) and water use efficiency (WUE) for maize in tropical conditions. Observed ET data were obtained using the Bowen ratio (BREB) method in Piracicaba-SP, and the soil water balance (SWB) method in Serra Talhada-PE. Simulations used the FAO-56 Penman-Monteith (ET_PM) or Priestley–Taylor (ET_PT) equations for ET, combined with the Ritchie (R-2) or Suleiman–Ritchie (S–R) methods for soil evaporation. The model was able to simulate daily and cumulative ET (Piracicaba irrigated: RMSE = 1.13–1.75 mm d⁻¹, d = 0.69–0.89 and bias = 4.92%–25.81%; Piracicaba rainfed: RMSE = 1.70–2.02 mm d⁻¹, d = 0.46–0.73 and bias = 21.10%–35.37%; Serra Talhada irrigated: RMSE = 0.95–1.42 mm d⁻¹ and d = 0.45–0.75 and bias = −20.74%–3.19%), daily ET by phenological phase (Piracicaba irrigated: RMSE = 1.60–3.18 mm d⁻¹ and d = 0.18–0.78; Piracicaba rainfed: RMSE = 1.59–2.27 mm d⁻¹ and d = 0.14–0.73; Serra Talhada irrigated: RMSE = 0.62–1.77 mm d⁻¹ and d = 0.54–0.87), WP and WUE (Piracicaba irrigated = 1.08–1.85 mm kg⁻³ and 3.15–4.64 mm kg⁻³; Piracicaba rainfed = 0.79–1.85 mm kg⁻³ and 2.63–4.64 mm kg⁻³; Serra Talhada irrigated = 0.80–1.12 mm kg⁻³ and 2.37–3.09 mm kg⁻³). The ET_PT method with the R-2 approach showed better agreement with observed data in Piracicaba-SP, while the ET_PM method combined with S–R performed better for the data from Serra Talhada-PE.

Plants have evolved complex cell-type-specific processes to adapt to a dynamic environment, exhibiting distinct signals in response to emerging drought stress. We propose an advanced qualitative and quantitative analysis approach, demonstrating tissue specificity in drought adaptation, which in turn may provide novel biological insights. This study represents the first comparative immunolocalization of cell components in wheat roots and leaves subjected to graded drought stress. Leaf and root samples of wheat were collected at 0, 5, and 20 days under control and drought conditions, and analysed by confocal microscopy. We performed immunofluorescence labeling of specific cellular components in situ, and the acquired data were analysed in terms of changes in quantitative and spatial fluorescence intensity. The qualitative analysis revealed differences in terms of individual components and individual days of the experiment. The quantitative analysis of leaf anatomy showed that the most pronounced changes were observed in the level of proteoglycans (JIM13, JIM15) and polysaccharides (LM5, LM16, LM20). The leaves of plants growing in drought were characterised by severely deformed tissue regions, in which increased secretion of extensins, AGPs, galactans, hemicelluloses, and RG-I was noted. In turn, the qualitative analyses of the microscopy images of roots, along with fluorescence intensity analyses, revealed a significantly higher content of AGP and arabinoxylan in the exodermis in plants grown under drought stress. The amount of LM2-recognised AGPs in the root exodermis increased fourfold after 20 days of drought compared with well-watered controls. Our research has revealed that the changes at the tissue level are spatially localised and highly specific, highlighting the dynamic nature of cell adaptation in response to water stress. The obtained results also emphasise the importance of in planta analyses, which indicate that findings from only single ex planta studies may distort the entire image of changes occurring in the plant as a result of stress.

Extreme rainfall events have increased in recent decades because of global warming, and sesame (Sesamum indicum L.) is sensitive to waterlogging stress. The study aimed to (i) identify traits associated with waterlogging stress tolerance during the seedling and flowering stages of sesame and (ii) quantify the effects of foliar spray of 100 μM melatonin on increasing the seed yield of waterlogged stressed plants. Experiments were conducted to quantify the effects of waterlogging stress during the seedling and flowering stages using 35 genotypes. The third and fourth experiments were conducted to mitigate waterlogging stress by foliar spraying with 100 μM melatonin. Compared to the irrigated control, waterlogging stress during the seedling stage decreased the stay-green score (72%) and survival percentage of the seedlings (61.4%). Similarly, at the flowering stage, waterlogging stress decreased the pod-set percentage (68%), the number of seeds per capsule (29%) and seed yield per plant (16%). A strong correlation existed between the stay-green score and seedling survival percentage (r² = 0.75). Similarly, a strong correlation existed between pod-set percentage and seed yield plant⁻¹ (r² = 0.64). Among the genotypes, VRI 1 and NIC 8252 were identified as stress-tolerant, and Co-1 and SI-1771 were susceptible. Under waterlogging stress, foliar spray of melatonin during seedling and flowering stages increased the number of seedling survival m⁻² (65%) and pod-set percentage (66%), respectively, over the unsprayed control, resulting in an increased seed yield. Overall, sesame seed yield under waterlogging stress can be improved by developing lines with high pod-set percentage and/or by foliar application of 100 μM melatonin.