In a two-year study, we quantified the important contribution of root architectural traits and key metabolic enzymes to wheat grain yield across varying nitrogen levels and soil depths. Two wheat varieties (Yannong 19 and Ningmai 13) were grown in specialized tubes under four N levels: 0, 120, 240, and 360 kg·ha⁻1 (N0–N3). N2 (240 kg·ha⁻1) significantly promoted root length, volume, and activities of nitrate reductase (NR) and glutamine synthetase (GS) at flowering. These growth and physiological improvements increased grain yield at maturity by 120.4

In the Huang-Huai-Hai region, high-temperature events frequently occur during the grain-filling stage, posing an increasing threat to winter wheat yield. Heat stress accelerates flag-leaf senescence and impairs post-anthesis photosynthesis, thereby limiting assimilate supply for grain filling. A two-year field experiment was conducted using the heat-tolerant cultivar ‘Huaimai 33’ (HM33) and the heat-sensitive cultivar ‘Fanmai 5’ (FM5). Trehalose (TRE) at 10, 15, and 20 mmol L⁻¹ was foliar-applied at anthesis, and passive warming was imposed from 15 days after anthesis for 5 consecutive days during grain filling. Grain yield, dry matter accumulation and allocation, flag-leaf photosynthetic characteristics, chlorophyll fluorescence, and sugar-related traits were determined. Heat stress markedly reduced grain yield and flag-leaf photosynthetic performance in both cultivars, with FM5 showing greater sensitivity than HM33. Among the TRE treatments, 15 mmol L⁻¹ TRE showed the greatest effect. Compared with the heat-stress treatment, 15 mmol L⁻¹ TRE increased grain yield by 5.40%–7.04% in HM33 and by 6.43%–9.76% in FM5 across the two growing seasons, mainly through increasing thousand-grain weight. At 21 days after anthesis, this treatment increased the net photosynthetic rate of flag leaves by 12.97% in HM33 and 19.08% in FM5. It also increased the proportion of dry matter allocated to grains at maturity from 42.56% to 46.28% in HM33 and from 43.86% to 48.42% in FM5. These results indicate that foliar application of 15 mmol L⁻¹ TRE alleviates terminal heat-induced yield loss by maintaining post-anthesis flag-leaf photosynthetic capacity and promoting assimilate allocation to grains. TRE application may provide a practical approach for improving wheat heat resilience during grain filling.

Nitrogen and potassium fertilization are key factors influencing the yield and quality of soft wheat. However, most existing studies have focused on single responses such as yield or grain protein content, and a systematic understanding of nitrogen–potassium interactions in regulating nitrogen metabolism and transport–partitioning processes, as well as their roles in the coordinated “high yield–low protein” mechanism, remains insufficient. This study investigated two soft wheat cultivars, Wanximai 0638 and Yangmai 20, under four nitrogen application levels (0, 150, 180, and 210 kg·ha⁻1), three N basal-to-topdressing ratios (8:2, 7:3, and 6:4), and two K fertilization treatments (single basal application versus split application at a 5:5 basal-to-topdressing ratio). The topdressing fertilizers were applied at the jointing stage. By analyzing indicators, including grain yield (GY), grain protein content (GPC), flour solvent retention capacity (SRC), nitrogen accumulation and translocation, nitrogen use efficiency (NUE), physiological nitrogen use efficiency (NPE), chlorophyll content (SPAD), and key nitrogen metabolism enzyme activities, the comprehensive effects of nitrogen application and potassium split application on soft wheat yield and quality were elucidated. The results revealed that the nitrogen rate, topdressing nitrogen ratio, and potassium split application method significantly influenced GY, GPC, SRC, nitrogen accumulation and translocation, NUE, NPE, SPAD, and nitrogen metabolism enzyme activities. With increasing nitrogen rate and topdressing proportion, activities of nitrogen metabolism enzymes were enhanced. Compared with 180 kg·ha⁻1 nitrogen and 7:3 or 8:2 base-to-topdressing ratios, applying 210 kg·ha⁻1 nitrogen with a 6:4 ratio increased pre-anthesis nitrogen translocation contribution to grains and post-anthesis nitrogen accumulation, leading to GY increase of 18.2

As spring cold events become more prevalent, low temperature has become a major abiotic stress factor limiting wheat yields in China. Previous studies have shown that spring cold spells lead to shrivelled grains and poor grain filling. To explore the physiological mechanisms underlying these effects, two wheat cultivars, 'Yannong 19' (low temperature-tolerant) and 'Wanmai 52' (low temperature-sensitive), were used. Controlled low-temperature treatments were applied in artificial climate chambers using three temperature levels (2 degrees C, 0 degrees C, and -2 degrees C) and two treatment durations (24 h and 48 h). This study evaluated the impact of low-temperature stress at the booting stage on grain yield, sucrose and starch accumulation, the activity and gene expression of starch-synthesizing enzymes, and the dynamics of dry matter accumulation and translocation. The results showed that low-temperature stress significantly decreased the number of grains per spike, thousand-grain weight, and grain starch content. Notably, these reductions were exacerbated with lower temperatures and longer exposure times. The activities of key starch-synthesizing enzymes, including invertase, starch phosphorylase 1, disproportionating enzyme 1, and ADP-glucose pyrophosphorylase, decreased progressively with decreasing treatment temperature and increasing stress duration. Meanwhile, the relative expression levels of starch synthesis-related genes in grains (AGPase, GBSSI, SSSI, SSSII, and Pho1) were significantly downregulated. After low-temperature stress, non-structural carbohydrate content in the stem sheaths decreased at heading but increased at maturity, indicating that the non-structural carbohydrate translocation amount, translocation rate, and its contribution to grain weight were reduced. Similarly, dry matter allocation and proportion in grains at maturity were significantly decreased. In summary, low-temperature stress during the booting stage suppresses starch synthesis initiation, starch accumulation and the translocation of assimilates to the grains, thereby significantly reducing wheat grain yield.

Global warming is primarily characterized by asymmetric temperature increases, with higher temperature rises in winter/spring and at night compared to summer/autumn and daytime. We investigated the impact of winter night warming on wheat leaves using the spring wheat cultivar Yangmai 18 and the semi-winter wheat cultivar Yannong 19 during the 2020–2021 growing season. This study aimed to examine the effect of winter night warming on the top expanded leaf of wheat plants. The results showed that the night mean temperature in the treatment group increased by 1.27°C compared to the ambient temperature and winter night warming increased the yield of both wheat cultivars, the activities of sucrose synthase and sucrose phosphate synthase after anthesis, and the biosynthesis of sucrose and soluble sugars. The differentially expressed genes were identified using P-value<0.05 and fold change>2, and subjected to Gene Ontology annotation and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses. The genes differentially expressed in wheat leaves treated with night warming were primarily associated with starch and sucrose metabolism, amino acid biosynthesis, carbon metabolism, plant hormone signal transduction, and amino sugar and nucleotide sugar metabolism. Comparison between groups identified 14 differentially expressed genes related to temperature. These results highlight the effects of winter night warming on wheat development from various perspectives. Our results provide new insights into the molecular mechanisms of the wheat response to winter night warming and the candidate genes involved in this process.

Nitric oxide (NO) positively contributes to maintaining a high photosynthetic rate in waterlogged-wheat plants by maintaining high stomatal conductance (gs), mesophyll conductance (gm), and electron transport rates in PSII (J). However, the molecular mechanisms underlying the synergistic regulation of photosynthetic characteristics during wheat waterlogging remain unclear. Pot experiments were conducted with two cultivars: Yangmai15 (YM15: high waterlogging-tolerance capacity) and Yangmai24 (YM24: conventional waterlogging-tolerance capacity). The 2 cm waterlogging depth treatment (WL), exogenous spraying of NO every two days in the WL treatment (WLsnp), and suitable soil water content treatment (CK) were established during the flowering stage for eight consecutive days. RNA-seq, weighted gene co-expression network analysis (WGCAN), and protein interaction analysis were performed on the 8th day to screen key genes that maintain high photosynthetic performance in waterlogged-wheat plants. The results indicated that cultivar YM24 and YM15 contained 10411 and 10582 differentially expressed genes (DEGs), respectively. The WL treatment had obviously higher DEGs than the WLsnp treatment compared to the CK treatment. Based on the WGCAN method, the DEGs were clustered into eight modules and correlated significantly with the four photosynthetic parameters mentioned above (P < 0.05). Only the DEGs in the ivory module (571) enriched the photosynthetic pathways among the eight modules. In the ivory module, 10 hub genes, including TaB1274F11.29-1, TaT6H20.190, TaOSNPB_100100300, TaLHCB, TaPSAG, TaCAP10B, TaFAD7A-1, TaCAB3C, TaT27G7, and TaF24G24.140, were screened using the co-expression network method because the genes exhibited similar variation trends with gs, gm, or J across the three water treatments and both cultivars. TaLHCB and TaCAP10B exhibited significant linear relationships with the three parameters of gs, gm, and J (P < 0.05). Consequently, TaLHCB and TaCAP10B genes are defined as waterlogging-resistance genes due to the synergistic regulation of photosynthetic characteristics in waterlogging. Both genes were significantly down-regulated in the WL treatment compared to CK treatment in both cultivars. However, there was no significant difference between WLsnp and CK treatments for the genes in the cultivar YM15. These results suggest that the positive effects of spraying NO with high waterlogging resistance capacities are linked to maintaining high expression levels of key genes and obtaining high photosynthetic characteristics during waterlogging, particularly for cultivars with high waterlogging resistance.

Low temperature (LT) in spring has become one of the principal abiotic stresses that restrict the growth and development of wheat. Diverse analyses were performed to investigate the mechanism underlying the response of wheat grain development to LT stress during booting. These included morphological observation, measurements of starch synthase activity, and determination of amylose and amylopectin content of wheat grain after exposure to treatment with LT during booting. Additionally, proteomic analysis was performed using tandem mass tags (TMT). Results showed that the plumpness of wheat grains decreased after LT stress. Moreover, the activities of sucrose synthase (SuS, EC 2.4.1.13) and ADP-glucose pyrophosphorylase (AGPase, EC 2.7.7.27) exhibited a significant reduction, leading to a significant reduction in the contents of amylose and amylopectin. A total of 509 differentially expressed proteins (DEPs) were identified by proteomics analysis. The Gene Ontology (GO) enrichment analysis showed that the protein difference multiple in the nutritional repository activity was the largest among the molecular functions, and the up-regulated seed storage protein (SSP) played an active role in the response of grains to LT stress and subsequent damage. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that LT stress reduced the expression of DEPs such as sucrose phosphate synthase (SPS), glucose-1-phosphate adenylyltransferase (glgC), and β-fructofuranosidase (FFase) in sucrose and starch metabolic pathways, thus affecting the synthesis of grain starch. In addition, many heat shock proteins (HSPs) were found in the protein processing in endoplasmic reticulum pathways, which can resist some damage caused by LT stress. These findings provide a new theoretical foundation for elucidating the underlying mechanism governing wheat yield development after exposure to LT stress in spring.

Global climate change is characterized by asymmetric warming, i.e., greater temperature increases in winter, spring, and nighttime than in summer, autumn, and daytime. Field experiments were conducted using four wheat cultivars, namely 'Yangmai 18' (YM18), 'Sumai 188' (SM188), 'Yannong 19' (YN19), and 'Annong 0711' (AN0711), in the two growing seasons of 2019-2020 and 2020-2021, with passive night warming during different periods in the early growth stage. The treatments were night warming during the tillering-jointing (NWT-J), jointing-booting (NWJ-B), and booting-anthesis (NWB-A) stages, with ambient temperature (NN) as the control. The effects of night warming during different stages on wheat yield formation were investigated by determining the characteristics of dry matter accumulation and translocation, as well as sucrose and starch accumulation in wheat grains. The wheat yields of all four cultivars were significantly higher in NWT-J than in NN in the 2-year experiment. The yield increases of semi-winter cultivars YN19 and AN0711 were greater than those of spring cultivars YM18 and SM188. Treatment NWT-J increased wheat yield mainly by increasing the 1,000-grain weight and the number of fertile spikelets, and it increased dry matter accumulation in various organs of wheat at the anthesis and maturity stages by increasing the growth rate at the vegetative growth stage. The flag leaf and spike showed the largest increases in dry matter accumulation. NWT-J also increased the grain sucrose and starch contents in the early and middle grain-filling stages, promoting yield formation. Overall, night warming between the tillering and jointing stages increased the preanthesis growth rate, and thus, wheat dry matter production, which contributed to an increase in wheat yield.

Low temperature(LT)in spring usually occurs at the booting of winter wheat,resulting in reduction of wheat yield.In this study,we used the LT-sensitive wheat cultivar'Wanmai 52'and the LT-insensitive wheat cul-tivar'Yannong 19'as experimental materials to conduct LT treatment(-2 ℃ and 0 ℃)at booting stage.After the LT treatment,we sprayed 6-benzylaminoadenine(6-BA)solutions with concentrations of 10,20,and 30 mg·L-1 respectively,with equal mass distilled water as control to investigate the effects of spraying 6-BA on the physiologi-cal characteristics,yield and quality of wheat flag leaves after LT stress at booting stage.The results showed that compared with the control,young ear of wheat treated with exogenous spraying 6-BA was fuller,the floret morphol-ogy was improved,and the number of vascular bundles under the spike was increased.6-BA application promoted the accumulation of soluble sugar,soluble protein,and proline in flag leaves.The activities of peroxidase and su-peroxide dismutase were increased,and the content of malondialdehyde was decreased.Exogenous 6-BA application decreased the number of degenerated spikes of wheat,increased the number of grains per spike and 1000-grain weight,as well as the contents of grain protein,wet gluten,and sedimentation value.In summary,exogenous 6-BA application could effectively alleviate the effects of LT stress on flag leaf and yield of wheat.Under the conditions of this experiment,the mitigation effect of spraying 6-BA solution on Yannong 19 was higher than that of Wanmai 52,and the mitigation effect of spraying 20 mg·L-1 6-BA solution on low temperature stress was the best.

Waterlogging during the anthesis, exacerbated by continuous rainy weather and heavy soil, has become a primary limiting factor affecting wheat yield in southern China's rice-wheat rotation regions. Previous research indicates that utilizing exogenous 6-benzylaminopurine (6-BA) can effectively alleviate the adverse effects of continuous rain on wheat yield, while the fundamental process is yet to be fully understood. In this research, two wheat varieties with contrasting waterlogging sensitivities were selected, which were exposed to waterlogging and shading for 7, 11, and 15 days after anthesis. Subsequently, three different concentrations of 6-BA solution (15, 25, and 35 mg L-1) were applied through spraying. The application of 6-BA significantly increased the total soluble sugar and starch content in grains during the filling process, as well as enhanced the activities of starch synthesis-related enzymes: sucrose synthase (SuS, EC 2.4.1.13), ADP-glucose pyrophosphorylase (AGPase, EC 2.7.7.21), and starch phosphorylase (Pho, EC 2.4.1.1). Moreover, the application of 6-BA notably enhanced the transfer and transport rate for non-structural carbohydrates (NSC) in the stem and sheath. It resulted in a notable increase in the distribution ratio of dry matter in the grain, ultimately leading to higher grain weight and yield. Applying 6-BA through spraying mitigated the adverse effects of waterlogging and shading on starch accumulation and dry matter transport in grains, thereby improving grain weight. The most effective concentration in this experiment was 25 mg L-1.

The effects of nitric oxide (NO) on the photosynthetic adaptation mechanisms of wheat plants in waterlogging during the flowering stage are poorly understood. Field and pot experiments using two cultivars were conducted with three treatments: waterlogging (WL), waterlogging plus NO donor sodium nitroprusside (WLsnp), and adequate water (CK). The results indicated that the WLsnp and CK treatments exhibited significantly higher 1000-kernel weight and yield than the WL treatment because of high photosynthetic potential(P<0.05). We found that the photosynthetic performance, including photosynthetic rate (P-n), stomatal conductance (g(s)), mesophyll conductance (g(m)), carbon dioxide concentration at the carboxylation site (C-c), maximum carboxylation rate (V-cmax), maximum electron transfer rate (J(max)), actual electron transfer rate (J), actual PSII efficiency (Phi(PSII)) and potential maximum efficiency in PSII (F-v/F-m), was significantly improved in the WLsnp treatment compared to the WL treatment, both during waterlogging and after de-waterlogging. Little difference was observed in the photosynthetic performance between the WLsnp and CK treatments during waterlogging for cultivar YM15 and after de-waterlogging for cultivar YM24. Further analysis indicated that g(s), g(m) and J were identified as key physiological indicators that synergistically regulate P-n of waterlogged wheat plants. Overall, the improvement of wheat's waterlogging resistance capacity after spraying NO is mainly related to high g(s), great g(m), and high J.

Global warming is asymmetric, with the increase in temperature at night being greater than that during the day. The objectives of this study were to assess the effects of night warming during different growth stages on the wheat grain yield, dry matter accumulation and distribution, photosynthetic characteristics, and enzymes related to sucrose metabolism. For that, field experiments with passive night warming were conducted using local spring type cultivars 'Yangmai 18 & PRIME; and 'Sumai 188 & PRIME; and semi-winter type cultivars 'Yannong 19 & PRIME; and 'Annong 0711 & PRIME; in two growing seasons in the Yangtze River Basin of China (average night time temperature increases of 1.45 & DEG;C and 1.56 & DEG;C for 2019-2020 and 2020-2021, respectively). The cultivars were exposed to night warming between four different growth stages (tillering to jointing [NWT-J], jointing to booting [NWJ-B], and booting to anthesis [NWB-A]) after 50% of plants had attained the treatment-start stage (tillering: Zadoks growth stage 21, main shoot and one tiller; jointing: Zadoks growth stage 31, the 1st node was detectable; booting: Zadoks growth stage 41, flag leaf sheath extension stage; anthesis: Zadoks growth stage 60, the beginning of pollination). Plants grown under ambient conditions were considered as the control (NN). Treatment NWT-J increased dry matter accumulation in flag leaves and spikes at anthesis and maturity, ultimately benefiting the yield, and the increase was higher in the semi-winter type cultivars. NWT-J increased not only the chlorophyll content, photosynthetic traits (net photosynthetic rate, stomatal conductance, and transpiration rate), and the activities of the maximum efficiency of PSII photochemistry under dark-adapted wheat flag leaves at the grain-filling stage (14 days after anthesis) but also the activities of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), fructose-1,6bisphosphatase (FBPase), and glycolate oxidase (GOX), and thus improved the photosynthetic capacity of wheat flag leaves and facilitating photosynthate accumulation. NWT-J also increased sucrose-phosphate synthase activity in flag leaves at the grain-filling stage, which could improve sucrose content. Collectively, early vegetative night warming (warming during tillering-jointing) improved the photosynthetic capacity of the flag leaves during the grain-filling stage and promoted the post-anthesis accumulation of dry matter and the transfer of dry matter to the grains, which ultimately benefited the yield.

为探究外源海藻糖(TRE)对高温胁迫下灌浆期不同耐性小麦品种旗叶生理特性和产量的影响作用,于2020—2022年在安徽农业大学高新技术农业园进行试验,选用前期筛选得的耐热性差异显著的敏感型小麦品种泛麦5号(Fanmai 5,FM5)和耐热型小麦品种淮麦33(Huaimai 33,HM33)作为试验材料,设置叶面喷施清水+不高温(CK1)、清水+灌浆期高温胁迫(CK2)、10 mmol L–1海藻糖+灌浆期高温胁迫(T10H)、15 mmol L–1海藻糖+灌浆期高温胁迫(T15H)和20 mmol L–1海藻糖+灌浆期高温胁迫(T20H)共5个处理.结果表明,在高温胁迫条件下,绿叶面积、叶绿素相对含量(SPAD)和干物质积累量均显著下降,与非高温逆境相比,高温胁迫下小麦产量显著下降,穗数和穗粒数无显著变化,千粒重是减产的主导因素.与喷清水相比,喷施海藻糖后产量较高温胁迫处理有所提升,各器官干物质积累量提高,丙二醛(MDA)含量降低,超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性提高,变化幅度在品种间存在差异,耐热品种的SPAD值降幅与丙二醛的增幅较小,但CAT活性的增幅较大,因而减产幅度较小.进一步的分析表明,净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、SPAD、SOD及POD和千粒重呈极显著正相关关系,MDA和产量呈极显著负相关关系.这些结果表明高温胁迫通过降低Pn、Gs和Tr抑制小麦的光合作用,减少光合产物的生成,造成最终的减产.喷施TRE,Pn、Gs、Tr、SPAD和CAT是降低高温胁迫伤害的主要指标,敏感品种缓解效果明显.此外,开花期喷施浓度15 mmol L–1海藻糖效果最好.该研究结果可为海藻糖对灌浆期高温胁迫下小麦光合响应差异机制和小麦抗氧化代谢提供理论依据.

为了选择适合稻茬弱筋小麦高产优质生产的合理施肥模式,以弱筋小麦宁麦13、皖西麦0638 为供试品种,设置不施肥(CK)、常规施肥复合肥+尿素(T1)、缓释掺混肥料(T2)、控失肥(T3)、腐殖酸复合肥(T4)、小麦配方肥(T5),在养分供应量相同的条件下,分析对稻茬弱筋小麦干物质分配及转运、灌浆、产量及品质的影响.结果表明:缓释掺混肥料与小麦配方肥较常规施肥能显著提高干物质在籽粒中的分配量及比例、花后干物质转运量并且提高小麦籽粒灌浆速率、延长有效灌浆天数、增加粒质量.缓释掺混肥料、控失肥、腐殖酸肥料、小麦配方肥处理较常规施肥均能显著提高小麦籽粒产量,施用缓释掺混肥料和小麦配方肥增产效果显著,显著增加有效穗数及千粒质量,产量分别较常规施肥增产9.27%～24.30%,11.64%～22.98%.缓释掺混肥料2a间两品种较常规施肥处理氮肥农学效率平均提高23.14%,36.88%,小麦配方肥2a两品种较常规施肥平均提高36.31%,39.35%.小麦配方肥处理2 个供试小麦品种籽粒品质均达到国家弱筋小麦标准.综上所述,小麦配方肥可作为试验地区稻茬弱筋小麦高产优质生产的施肥模式之一,或适当降低缓释掺混肥料的施用量作为稻茬弱筋小麦的高产优质生产施肥模式之一.

With the continuous change of global climate, the frequency of low-temperature stress (LTS) in spring increased greatly, which led to the increase of wheat yield decline. The effects of LTS at booting on grain starch synthesis and yield were examined in two wheat varieties with differing low-temperature sensitivities (insensitive variety Yannong 19 and sensitive variety Wanmai 52). A combination of potted and field planting was employed. For LTS treatment at booting, the wheat plants were placed in a climate chamber for 24 h at −2°C, 0°C or 2°C from 19:00 to 07:00 then 5°C from 07:00 to 19:00. They were then returned to the experimental field. The effects of flag leaf photosynthetic characteristics, the accumulation and distribution of photosynthetic products, enzyme activity related to starch synthesis and relative expression, the starch content, and grain yield were determined. LTS at booting caused a significant reduction in the net photosynthetic rate ( P n ), stomatal conductance ( G s ), and transpiration rate ( T r ) of the flag leaves at filling. The development of starch grains in the endosperm is also hindere, there are obvious equatorial grooves observed on the surface of the A-type starch granules, and a reduction in the number of B-type starch granules. The abundance of 13 C in the flag leaves and grains decreased significantly. LTS also caused a significant reduction in translocation amount of pre-anthesis stored dry matte from vegetative organs to grains and amount of post-anthesis transfer of accumulated dry matte into grains, and the distribution rate of dry matter in the grains at maturity. The grain filling time was shortened, and the grain filling rate decreased. A decrease in the activity and relative expression of enzymes related to starch synthesis was also observed, with a decrease in the total starch content. As a result, a decrease in the grain number per panicle and 1000-grain weight were also observed. These findings highlight the underlying physiological cause of decreased starch content and grain weight after LTS in wheat.

In recent years, due to the frequent occurrence of extreme weather, low temperatures（LT）became one of the main disasters restricting wheat production. LT has negative effects on wheat growth and yield formation, especially at booting stage. Exogenous spraying of 6-benzylamino adenine（6-BA）after LT at booting stage can alleviate the damage caused by LT in wheat, but the related molecular regulation mechanism is still unclear. In this study, transcriptome sequencing technology was used to analyze the molecular mechanism of 6-BA improving cold tolerance in wheat. The LT sensitive variety Wanmai 52 and insensitive variety Yannong 19 were selected as the experimental materials. The experiment was carried out in combination of potted and field planting. Two wheat cultivars were planted in plastic pots at a planting density of ten plants per pot. At booting stage, the pots were moved into an artificial climate chamber for low temperature treatment. At the end of the treatment, 20 mg L–1 6-BA solution was sprayed, and an equal volume of distilled water was sprayed as the control. The morphology of young spike, and the content of soluble sugar and starch in young spikes were determined. Some candidate differentially expressed genes（DEGs）were screened and their relative expression patterns were analyzed by qRT-PCR, and the results were verified by qRT-PCR. After 10days, compared with the control, the morphological development of young spike was better, fuller and longer. The contents of soluble sugar and starch in young spikes increased after 6-BA treatment. The results showed that 22,770 DEGs were identified in Wanmai 52 and 9866 in Yannong 19, respectively, and 661 genes were up-regulated in the two cultivars. ARF5, AGPL1, 1-SST,SWEET15, and other genes were screened out, which were related to the regulation of plant hormone level, starch synthesis, and sugar metabolism. GO and KEGG enrichment analysis were performed on the selected differential genes. GO annotation revealed that the functions of the differential genes of the two varieties were mainly concentrated in cell structure stability, metabolism, and catalytic activity. KEGG enrichment analysis demonstrated that signal transduction, regulation of endogenous hormone levels,carbon metabolism, the changes of membrane structure and function had significant changes. In conclusion, 6-BA could alleviate cold damage by regulating the metabolism of antioxidant substances, hormone signal transduction, carbohydrate metabolism,osmotic adjustment, and other ways in wheat. The results provide a theoretical basis for exploring the cultivation measures to reduce the damage of low temperature on wheat in spring.

Taking the heat-sensitive wheat variety 'Fanmai 5' (FM5) and the heat-tolerant variety 'Huaimai 33' (HM33), which were screened out in the previous experiments, as experimental materials, we conducted a field experiment with passive heat-enhancing shelters to simulate post-flowering high-temperature environment (average temperature increase of 5.13 ℃) during 2021-2022. During the filling period, we analyzed the effects of exogenous trehalose (10, 15 and 20 mmol·L-1) on the filling characteristics and sugar fraction under high temperature, with no spraying at ordinary temperature as control (CK). The results showed that treating without spraying exogenous trehalose at high temperature (H) significantly reduced wheat grain yield and grain weight during the filling period, and spraying exogenous trehalose alleviated the reduction of grain yield and grain weight at the filling stage under high temperature stress. Compared with the H treatment, grain yield and grain weight of HM33 and FM5 wheat varie-ties increased by 3.5%, 6.7% and 4.2%, 5.4%, respectively. High temperature stress significantly increased the trehalose content and trehalase (THL) activity in flag leaves of both wheat varieties, and decreased the fructose and glucose contents. Spraying exogenous trehalose increased the contents of trehalose, fructose, and glucose in flag leaves, and decreased the trehalase activity in flag leaves compared with H treatment, which could improve the glucose metabolism capacity of wheat at filling stage. The increasing effect of FM5 was higher than that of HM33. High temperature stress significantly reduced starch content of flag leaves and grains, while spraying exogenous trehalose alleviated the decrease of starch content of flag leaves and grains under high temperature stress, which was profit able for the substance accumulation of wheat grains under high temperature stress. Under the conditions of this experiment, spraying 15 mmol·L-1 trehalose at flowering stage was the best treatment for the two wheat varieties.

To explore suitable nitrogen application levels for weak gluten wheat after rice stubble in Anhui Province’s Huaihe River region, a field experiment was conducted using 5 nitrogen application levels(0, 75, 150, 225, and 300 kg·hm -2 ). The study investigated the effects of nitrogen application on yield, quality, dry matter accumulation and transport, and nitrogen use efficiency of wheat. The results showed that in the range of 0-300 kg·hm -2 nitrogen application level, with the increase of nitrogen application, the number of tillers, plant height, leaf area index（LAI） and chlorophyll relative content（SPAD） of wheat showed an upward trend. 21 days after anthesis, the spectral reflectance of wheat canopy gradually increased in the band of 760-925 nm, and first increased and then decreased in the band of 925-1 300 nm. From booting to maturity, dry matter accumulation and transport of pre-anthesis vegetative organs increased initially then declined with increasing nitrogen application level, the contribution rate of dry matter transport of pre anthesis vegetative organs to grains continued to decline, while the post anthesis dry matter production and its contribution rate to grains gradually increased. The number of grains per ear and effective ears increased with increasing nitrogen application level, the 1 000 grain weight and grain yield of wheat showed a trend of increasing first and then decreasing, reaching maximum grain yield at 225 kg·hm -2 nitrogen application level. Compared with the treatment without nitrogen application, grain yields at location I and II increased by 127.58%-230.45% and 72.21%-131.94% when nitrogen application level was 75-300 kg·hm -2 . As the nitrogen application level increased, the apparent utilization rate, agronomic utilization rate, and partial productivity of nitrogen fertilizer gradually decreased. The wheat grain quality index was better at a nitrogen application level of 225 kg·hm -2 , but when the nitrogen application level was 300 kg·hm -2 , the wheat grain protein content exceeded the national protein content standard of weak gluten wheat. Compared to the treatment without nitrogen application, the wheat grain protein content increased by 12.02%-44.21% and 9.64%-34.30% at the two test points when the nitrogen application level was between 75-300 kg·hm -2 . Overall, when the nitrogen application level was 225 kg·hm -2 , the wheat grain quality index was better, and the yield was the highest. Considering the selection criteria of high yield and high quality, 225 kg·hm -2 was identified as the suitable nitrogen application level for weak gluten wheat in the rice stubble region along the Huaihe River in Anhui Province.

为研究不同外源修复物质对受渍小麦根系生长发育的影响,以扬麦18 为材料,在开花期设置渍水 9 d(W9)和正常灌溉(W0)处理,两处理分别叶面喷施蒸馏水(T0)、0.01 mmol·L-16-BA(T1)、0.3%KH2PO4(T2)、0.01 mmol·L-16-BA和0.3%KH2PO4 复配溶液(T3),研究不同外源物质对小麦根系抗氧化酶和无氧呼吸酶活性的影响.结果表明,W0 条件下,喷施 0.3%KH2PO4 和 0.01 mmol·L 6-BA可以改善根系中超氧化物歧化酶(SOD)、过氧化物酶(POD)、乙醇脱氢酶(ADH)活性,提高小麦千粒重,进而提高产量;W9 处理中,小麦0～60 cm土层根系中SOD、ADH、乳酸脱氢酶(LDH)活性均有不同程度降低,而POD活性、丙二醛(MDA)含量显著提高,而喷施0.3%KH2PO4 和0.01 mmol·L 6-BA显著提高了各土层根系SOD、ADH、LDH活性,降低POD活性和MDA含量,其中,喷施0.01 mmol·L-16-BA和0.3%KH2PO4 复配剂显著提高了小麦根系抗氧化能力和无氧呼吸能力,其成熟期千粒重和产量分别比渍水处理提高23.34%、37.43%.