Effects of water stress on starch synthesis and accumulation of two rice cultivars at different growth stages

Yield and rice quality indicators of crops are a direct reflection of the rational irrigation and fertilizer strategy. However, the effects of controlled irrigation (CI) combined with the split application of fertilization managements (straw returning, organic fertilizer, and conventional fertilizer) on rice quality are not clear in southeast China. This study aims at exploring the effects of three fertilization managements applied under CI or flooding irrigation on rice yield, quality, enzyme activity, and soluble sugar content including 43 indicators, to determine the optimal comprehensive evaluation model, management, and representative indexes. The results showed that compared with CF (CI + conventional fertilizer), CS (CI + straw returning) significantly increased yield (27.65%), irrigation water use efficiency (6.20%), chalky grain rate (9.67%), chalkiness (1.83%), protein content (4.29%), and amylose content (0.33%), indicating that CS improved yield and milling quality but decreased cooking and appearance quality. This was mainly because CS promoted the activities of alpha-amylase, ADPG (ADP-glucose pyrophosphorylase), and GBSS (granule-bound starch synthase) and reduced the soluble sugar content in rice. Grey relational degree analysis (GRD), the entropy method (ETM), and TOPSIS (the technique for order preference by similarity to an ideal solution) were used to comprehensively evaluate the rice quality and determined that CS treatments could synergistically improve yield and rice quality. The five indexes (adhesive strength, HPV, ADPG, soluble sugar (leaf), yield) and TOPSIS model can be used as the best indexes and model to evaluate the rice quality. These results could provide scientific management and evaluate practices for high-yield and high-quality rice cultivation, which may be promising for a cleaner production strategy.

Section: Enzyme Activity and Soluble Sugar Content Measurementmentioning

confidence: 99%

Effects of Irrigation and Fertilization Management on Yield and Quality of Rice and the Establishment of a Quality Evaluation System

Hu,

Zhang,

Yang

et al. 2023

“…Drought stress can reduce the β-glucan content in barleys during the filling period [18]. In the booting stage, flowering stage and filling stage, mild drought increased the starch content of rice (NJ9108) by 1.11%, 2.52% and 3.54%, while severe drought decreased the starch content by 12.49%, 8.87% and 5.86% [19]. Severe drought at the jointing stage reduced the amylose content of rice (SJ6) by 15.61% and increased amylopectin content by 7.21% [20].…”

Section: Introductionmentioning

confidence: 99%

Metabolomics and Physiological Methods Revealed the Effects of Drought Stress on the Quality of Broomcorn Millet during the Flowering Stage

Ren,

Liu,

Mao

et al. 2024

The flowering stage is a critical period for water sensitivity and quality formation of broomcorn millets. However, the effects and mechanisms of drought stress on the quality formation of broomcorn millets are not clear. We used the drought-resistant variety Hequ red millet (H) and the drought-sensitive variety Yanshu No. 10 (Y) were used as materials for drought stress treatment during the flowering stage, metabolomics and physiological methods were used to study the differences in protein, starch, amino acids, medium and medium-long chain fatty acids, and their response characteristics to drought in broomcorn millet. The results showed that different genotypes of broomcorn millets exhibited different response mechanisms in the face of drought stress. In Hequ red millet, drought stress significantly increased the contents of amylopectin (2.57%), pyridoxine (31.89%), and anthocyanin, and significantly decreased the contents of water-soluble protein (5.82%), glutelin (10.07%), thiamine (14.95%) and nicotinamide (23.01%). In Yanshu No. 10, drought significantly decreased amylose by 6.05%, and significantly increased riboflavin and nicotinamide contents by 21.11% and 32.59%. Correlation analysis showed that total starch and amylose were highly significantly positively correlated with methyl palmitate; negatively correlated with amylopectin, vitamins, proteins, free amino acids, and medium-long chain fatty acids; and amylopectin was significantly positively correlated with water-soluble protein, riboflavin, and pyridoxine. Water-soluble protein and glutelin were significantly positively correlated with most free amino acids, medium-long chain fatty acids, and nicotinamide. Thiamine showed significant positive correlation with nicotinamide and significant negative correlation with pyridoxine. Riboflavin was significantly positively correlated with nicotinamide, pyridoxine, and water-soluble protein, and pyridoxine was significantly positively correlated with water-soluble protein. Hequ red millet transforms into amylopectin by consuming water-soluble protein and glutelin, and improves drought resistance by accumulating pyridoxine, and changes its physicochemical properties by decreasing the content of amylose and protein and elevating the content of amylopectin. Yanshu No. 10 resisted drought by catabolizing lipids to produce fatty acids and by consuming amylose for conversion into other metabolites. The present study helps to understand the response of the nutritional quality of millets to drought stress at the flowering stage and provides a theoretical basis for the selection and breeding of superior varieties of millets and drought resistance research.

“…It is reported that by 2050, there will be a 60% increase in rice (Oryza sativa L.) production to meet the escalating demand for food [2]. However, crops are struggling to cope with the diminishing water resources [3,4]. Rice, being a vital crop, is known for its high water requirements, with irrigation accounting for approximately 80% of the total water usage in Asian agriculture [5,6].…”

Section: Introductionmentioning

confidence: 99%

A Moderate Wetting and Drying Regime Combined with Appropriate Nitrogen Application Increases Grain Yield and Nitrogen Use Efficiency in Rice

Huang

et al. 2023

This study investigated whether and how irrigation regimes interact with nitrogen (N) application rates to mediate the grain yield, N use efficiency (NUE) and water use efficiency (WUE) in rice and to understand the underlying mechanism. A field experiment was conducted with two irrigation regimes, continuously flooded (CF) and alternate wetting and moderate drying (AWMD), and three N application rates, 120 kg ha−1 N (a low N rate, LN), 240 kg ha−1 N (a medium N rate, MN) and 360 kg ha−1 N (a high N rate, HN) in 2021 and 2022. The results showed that the grain yield exhibited the lowest values at the LN, regardless of the irrigation regime, while it was the highest at the MN when the CF regime was adopted. The grain yield was comparable between the MN and HN regarding the AWMD regime. AWMD significantly increased the grain yield, NUE and WUE compared to CF at the same N rate, which was attributed to a higher photosynthetic rate, improved population quality, enhanced nonstructural carbohydrate remobilization from stems to grains during grain filling, and elevated activities of enzymes involved in N assimilation in the roots. The results suggest that an AWMD regime combined with MN treatment could pronounce a synergistic interaction on the grain yield, NUE and WUE in rice by improving root and shoot physiological performances.