Wheat production is largely restricted by adverse environmental stresses. Under many undesirable conditions, endoplasmic reticulum (ER) stress can be induced. However, the physiological and molecular responses of wheat to ER stress remain poorly understood. We used dithiothreitol (DTT) and tauroursodeoxycholic acid (TUDCA) to induce or suppress ER stress in wheat cells, respectively, with the aim to reveal the molecular background of ER stress responses using a combined approach of transcriptional profiling and morpho-physiological characterization. To understand the mechanism of wheat response to ER stress, three wheat cultivars were used in our pre-experiments. Among them, the cultivar with a moderate stress tolerance, Yunong211 was used in the following experiments. We used DTT (7.5 mM) to induce ER stress and TUDCA (25 μg·mL− 1) to suppress the stress. Under three treatment groups (Control, DTT and DTT + TUDCA), we firstly monitored the morphological, physiological and cytological changes of wheat seedlings. Then we collected leaf samples from each group for RNA extraction, library construction and RNA sequencing on an Illumina Hiseq platform. The sequencing data was then validated by qRT-PCR. Morpho-physiological results showed DTT significantly reduced plant height and biomass, decreased contents of chlorophyll and water, increased electrolyte leakage rate and antioxidant enzymes activity, and accelerated the cell death ratio, whereas these changes were all remarkably alleviated after TUDCA co-treatment. Therefore, RNA sequencing was performed to determine the genes involved in regulating wheat response to stress. Transcriptomic analysis revealed that 8204 genes were differentially expressed in three treatment groups. Among these genes, 158 photosynthesis-related genes, 42 antioxidant enzyme genes, 318 plant hormone-related genes and 457 transcription factors (TFs) may play vital roles in regulating wheat response to ER stress. Based on the comprehensive analysis, we propose a hypothetical model to elucidate possible mechanisms of how plants adapt to environmental stresses. We identified several important genes that may play vital roles in wheat responding to ER stress. This work should lay the foundations of future studies in plant response to environmental stresses.

Calibration and experiment of the discrete element parameters of watermelon seeds

Addressing the issues of poor performance and low single-seed rate during seed filling and cleaning for corn, an airsuction roller precision dibbler was designed, and its main structure and working principle were elaborated. Based on the structure of the seed metering disk and the tri-axial dimensions of corn seeds, an auxiliary filling type hole boss was designed with a radius of 4 mm and a thickness of 1.5 mm. A sawtooth-type seed cleaning device was also designed, with an installation angle greater than 3° and a serrated chamfer less than 62.1°. By coupling the Discrete Element Method (EDEM) with Computational Fluid Dynamics (CFD), the flow field structure and seed metering performance were simulated and analyzed, examining the movement states of the seed population and individual seeds during the processes of filling, cleaning, carrying, and initial seed dropping. The variation patterns of the internal flow field pressure and fluid velocity of the seed metering device under different negative pressures and operating speeds were studied. Through the construction of a test bench and single-factor and three-factor orthogonal experiments, along with multi-objective optimization methods, the primary and secondary factors affecting the qualification index were determined. The optimization results showed that when the flow field negative pressure was 3.52 kPa, the operating speed was 5.81 km/h, and the suction hole diameter was 4.15 mm, the qualification index of the seed metering device was 93.2%, the missed seeding index was 3.3%, and the multiple seeding index was 3.5%. An adaptability test was conducted to verify these results, revealing that the qualification index for all three varieties of corn seeds exceeded 92.4%, the missed seeding index was less than 3.7%, and the multiple seeding index was less than 3.9%, satisfying the precision seeding requirements for corn seeds.