High Salinity is a major environmental stress influencing growth and development of rice. Comparative proteomic analysis of hybrid rice shoot proteins from Shanyou 10 seedlings, a salt-tolerant hybrid variety, and Liangyoupeijiu seedlings, a salt-sensitive hybrid variety, was performed to identify new components involved in salt-stress signaling.

Post-anthesis nitrogen uptake and translocation play critical roles in photosynthetic assimilation and grain filling. However, their effects on leaf stay-green characteristics, dry matter accumulation, and translocation after anthesis remain unclear. In this study, post-anthesis N uptake and translocation between two different rice genotypes (Yongyou12 and Zhongzheyou1) were compared through soil nitrogen leaching treatments at the meiosis stage (MST) and anthesis stage(AST) respectively, and their effects on leaf stay-green duration, photosynthesis, dry matter accumulation and translocation during ripening and yield formation were estimated. The results showed that the soil nitrate-N and ammonium-N contents in Yongyou12 pots decreased significantly, and post-anthesis N uptake was 2.0–3.4 fold higher in Yongyou12 than in Zhongzheyou1. The activities of N-metabolism enzymes and antioxidant enzymes were higher, and flag-leaf photosynthesis and dry matter accumulation during ripening were greater, in Yongyou12 than in Zhongzheyou1. However, insufficient available soil N led to significant decreases in the activities of N- metabolism enzymes, decreased flag-leaf photosynthesis, increased translocation of dry matter and N pre-anthesis, accelerated leaf senescence, shorter duration of the leaf stay-green period, and decreased dry matter accumulation and grain plumpness. In addition, the effect of N uptake after anthesis on yield is greater for rice genotypes that depend on post-anthesis dry matter accumulation and an expanded sink capacity.

The application of nitrogen (N) fertilizer deep in soil at the same time as mechanical transplanting of rice seedlings is an effective alternative to conventional broadcasting of fertilizer, but its effects on yields and profitability have not been analysed in detail. Here, we analysed the effects of a side deep application of N fertilizer at transplanting on the N uptake, N use efficiency (NUE), grain yield, and economic profitability of two rice (Oryza sativa L.) cultivars; Yongxian15 (early season) and Yongyou1540 (middle/late season). In the field experiments, two types of N fertilizer (urea (U) and controlled-release urea (CRU)) were surface broadcasted manually (B) or mechanically fertilized at 5.5 ± 0.5 cm soil depth (M) (UB, UM, and CRUM treatments, respectively). The blank control had no N fertilizer (N0). Each N-fertilizer treatment had similar effects on N uptake, grain yield, NUE, and economic profitability in the early, middle, and late seasons. Compared with manually applied fertilizer, mechanically applied fertilizer increased grain yield and NUE in both cultivars. In Yongxian15 and Yongyou1540, the mechanical side deep application of N-fertilizer increased the N recovery efficiency by 62.50–91.57% and 24.38–64.24%, respectively, the N agronomy efficiency by 33.65–63.14% and 22.64–44.70%, respectively; and the grain yield by 6.30–11.64% and 6.23–13.11%, respectively. The CRUM treatments had the highest benefit–cost ratio because of high gross returns and low fertilization costs. The mechanized side deep application of N fertilizer can increase the efficiency and profitability of rice production.

Quick access to cadmium (Cd) contamination in lettuce is important to supervise the leafy vegetable growth environment and market. This study aims to apply laser-induced breakdown spectroscopy (LIBS) technology for fast determination of Cd content and diagnosis of the Cd contamination degree in lettuce. Emission lines Cd II 214.44 nm, Cd II 226.50 nm, and Cd I 228.80 nm were selected to establish the univariate analysis model. Multivariate analysis including partial least squares (PLS) regression, was used to establish Cd content calibration models, and PLS model based on 22 variables selected by genetic algorithm (GA) obtained the best performance with correlation coefficient in the prediction set Rp² = 0.9716, limit of detection (LOD) = 1.7 mg/kg. K-Nearest Neighbors (KNN) and random forest (RF) were used to analyze Cd contamination degree, and RF model obtained the correct classification rate of 100% in prediction set. The preliminary results indicate LIBS coupled with chemometrics could be used as a fast, efficient and low-cost method to assess Cd contamination in the vegetable industry.

Submergence stress is a limiting factor for rice growing in rainfed lowland areas of the world. It is known that the phytohormone gibberellin (GA) has negative effects on submergence tolerance in rice, while its inhibitor paclobutrazol (PB) does the opposite. However, the physiological and molecular basis underlying the GA- and PB-regulated submergence response remains largely unknown. In this study, we reveal that PB could significantly enhance rice seedling survival by retaining a higher level of chlorophyll content and alcohol dehydrogenase activity, and decelerating the consumption of non-structure carbohydrate when compared with the control and GA-treated samples. Further transcriptomic analysis identified 3936 differentially expressed genes (DEGs) among the GA- and PB-treated samples and control, which are extensively involved in the submergence and other abiotic stress responses, phytohormone biosynthesis and signaling, photosynthesis, and nutrient metabolism. The results suggested that PB enhances rice survival under submergence through maintaining the photosynthesis capacity and reducing nutrient metabolism. Taken together, the current study provided new insight into the mechanism of phytohormone-regulated submergence response in rice.

Machine transplanting technology of biodegradable films has solved the problems of the higher cost of artificial film and the serious environmental pollution of polyethylene film residue. Previous studies have shown the positive impact of mulching on mitigating global warming potential. However, the mechanisms underlying the association between greenhouse gas emissions and the bacterial community structure in paddy field soil with biodegradable film mulching (BM) still remain limited. In this study, greenhouse gas emissions and the associated bacterial community in non-mulching, biodegradable mulching in a paddy field in Eastern China were analyzed over the 2019 and 2020 rice growing seasons. Rice mulching cultivation significantly inhibited CH₄ emissions from a rice paddy, mainly due to the significant reduction in methane emission peaks. Film mulching significantly increased the diversity of the bacterial community as revealed by 16S rRNA gene sequencing. The relative abundance of methanogens was decreased, while the relative abundance of methanotrophs was increased in the paddy soil due to the BM treatment, with the change pattern basically consistent with CH₄ emissions. The N₂O emissions during the growth period showed a pronounced downward trend. However, the total abundance of bacteria involved in nitrification and denitrification was higher under BM. Mulching cultivation improved the soil nutrient availability and significantly increased the yield by 5.0%. BM inhibited the greenhouse gas emission intensity (GHGI) of the paddy field by 46.9%. Film mechanical transplanting could promote yield increases and significantly mediate the warming potential (GWP) of greenhouse gases in the paddy fields of the Middle-Lower Yangtze Area. The rational use of film mechanical transplanting would play a role in carbon neutrality in paddy fields. This study provided a theoretical basis for paddy field emission reduction and sustainable agricultural development.