Background The middle and lower reaches of the Yangtze River plain produce the second highest amount of wheat in China; however, waterlogging is an important environmental factor that substantially affects the yield production of wheat (Triticum aestivum L.) in this region. Methods In this study, seven treatments were implemented, including no waterlogging and exogenous 6-benzylaminopurine (6-BA) as a control (CK); waterlogging at booting (BW), anthesis (AW) and 15 days after anthesis (DAA, FW); and spraying 6-BA before waterlogging at booting (BW-6BA), anthesis (AW-6BA) and 15 DAA (FW-6BA), to determine the ability of 6-BA to alleviate the harmful impact of waterlogging on aboveground biomass production and grain yield. The widely cultivated wheat cultivar “Zhengmai 9023” was used. Results The results showed that more than 190.0 mm of rainfall, which accounted for approximately 45.0% of the precipitation over the whole wheat growing season, was distributed after the booting stage (April and May). In all waterlogged treatments, the photosynthetic rate, aboveground biomass and grain yield decreased, but the differences between the CK and the FW treatment were not significant. The grain yield decreased by 18.38%, 41.79% and 5.67% in the BW, AW and FW treatments, respectively. Spraying 6-BA before waterlogging enhanced the root activities after anthesis and then decreased the malondialdehyde concentrations of the flag leaves and the third leaf, increased the photosynthetic rate of the flag leaves and enhanced aboveground biomass and grain yield. Among the increments between the treatments, the increments between the BW and BW-6BA treatments were the largest, but between the FW and FW-6BA were smallest. In comparison to the other waterlogging treatments, the grain yields from the FW and FW-6BA treatments were significantly higher because of the higher kernel numbers per spike. The results indicated that waterlogging after the booting stage restrained the dry matter production of winter wheat, but spraying 6-BA before waterlogging slowed the plant senescence rate and reduced grain yield loss.

Increased attention on the agricultural impacts to environment has revealed excessive N input to be a major concern. Sowing date reportedly impacts crop N uptake, however, few studies have assessed the effects of late sowing with reduced N apply on crop N status and grain yield. We evaluated three treatments: normal sowing (8 October), late sowing (22 October), and optimized late sowing (22 October, with 75% N application) over two wheat (Triticum aestivum L.) growing seasons (2017)(2018)(2019), and assessed their effects on crop N status, N allocation and use, net photosynthetic rate (P max ), grain yield, and soil N budget. Compared to normal sowing, optimized late sowing resulted in near-optimum N status, improved nitrogen use efficiency (NUE), nitrogen utilization efficiency (UTE), and nitrogen uptake efficiency (UPE), while maintaining a high yield. Although aboveground N uptake of late and optimized late sowing at anthesis was lower than that of normal sowing, N distribution was more optimized, mainly manifesting as: unchanged N allocation to the individual plant, but increased N allocation to flag leaf, and steeper green leaf area N in the canopy under optimized late sowing. Optimized N nutrition index and N distribution under late sowing contributed to a higher P max , which resulted in a higher dry matter accumulation rate during post-anthesis, and ultimately a consistent grain yield among the three treatments. Moreover, N input reduction under optimized late sowing decreased the final mineral N in the 0-100-cm soil layer at harvest and apparent N loss, which reduced environmental pollution and resources waste.Abbreviations: AGN, aboveground nitrogen uptake; N f-min , final mineral N in the 0-100-cm soil layer at harvest; N loss , apparent N loss; NNI, nitrogen nutrition index; NUE, nitrogen use efficiency; P max , net photosynthetic rate; SLN, specific green leaf area nitrogen; UPE, nitrogen uptake efficiency; UTE, nitrogen utilization efficiency.

Wheat (Triticum aestivum L.), the most widely cultivated crop, is affected by waterlogging that limited the wheat production. Given the incompleteness of its genome annotation, PacBio SMRT plus Illumina short-read sequencing strategy provided an efficient approach to investigate the genetic regulation of waterlogging stress in wheat. A total of 947,505 full-length non-chimetric (FLNC) sequences were obtained with two wheat cultivars (XM55 and YM158) with PacBio sequencing. Of these, 5,309 long-non-coding RNAs, 1,574 fusion genes and 739 transcription factors were identified with the FLNC sequences. These full-length transcripts were derived from 49,368 genes, including 47.28% of the genes annotated in IWGSC RefSeq v1.0 and 40.86% genes encoded two or more isoforms, while 27.31% genes in the genome annotation of IWGSC RefSeq v1.0 were multiple-exon genes encoding two or more isoforms. Meanwhile, the individuals with waterlogging treatments (WL) and control group (CK) were selected for Illumina sequencing. Totally, 6,829 differentially expressed genes (DEGs) were detected from four pairwise comparisons. Notably, 942 DEGs were overlapped in the two comparisons (i.e., XM55-WL vs. YM158-WL and YM158-WL vs. YM158-CK). Undoubtedly, the genes involved in photosynthesis were downregulated after waterlogging treatment in two cultivars. Notably, the genes related to steroid biosynthesis, steroid hormone biosynthesis, and downstream plant hormone signal transduction were significantly upregulated after the waterlogging treatment, and the YM158 variety revealed different genetic regulation patterns compared with XM55. The findings provided valuable insights into unveiling regulation mechanisms of waterlogging stress in wheat at anthesis and contributed to molecular selective breeding of new wheat cultivars in future.

Transient and chronic waterlogging constrains crop production in many regions of the world. Here, we invoke a novel iTRAQ-based proteomic strategy to elicit protein synthesis and regulation responses to waterlogging in tolerant (XM 55) and sensitive genotypes (YM 158). Of the 7,710 proteins identified, 16 were distinct between the two genotypes under waterlogging, partially defining a proteomic basis for waterlogging tolerance (and sensitivity). We found that 11 proteins were up-regulated and 5 proteins were down-regulated; the former included an Fe-S cluster assembly factor, heat shock cognate 70, GTP-binding protein SAR1A-like and CBS domain-containing protein. Down-regulated proteins contained photosystem II reaction center protein H, carotenoid 9, 10 (9′, 10′)-cleavage dioxygenase-like, psbP-like protein 1 and mitochondrial ATPase inhibitor. We showed that nine proteins responded to waterlogging with non-cultivar specificity: these included 3-isopropylmalate dehydratase large subunit, solanesyl-diphosphate synthase 2, DEAD-box ATP-dependent RNA helicase 3, and 3 predicted or uncharacterized proteins. Sixteen of the 28 selected proteins showed consistent expression patterns between mRNA and protein levels. We conclude that waterlogging stress may redirect protein synthesis, reduce chlorophyll synthesis and enzyme abundance involved in photorespiration, thus influencing synthesis of other metabolic enzymes. Collectively, these factors accelerate the accumulation of harmful metabolites in leaves in waterlogging-susceptible genotypes. The differentially expressed proteins enumerated here could be used as biological markers for enhancing waterlogging tolerance as part of future crop breeding programs.

With the development of quality education, Ordinary Differential Equation, as a basic course of mathematics major in colleges and universities, has been reformed, innovated and developed. Especially under the support of education informatization, micro class and flipped classroom are widely used in the teaching of Ordinary Differential Equation, which has a positive impact on improving its teaching quality and efficiency. This paper starts with the necessity of the application of flipped classroom teaching mode supported by micro course in the teaching of Ordinary Differential Equation, and explores the specific application strategy research in the course practice, aiming to provide reference for other professional courses teaching reform.