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Nitrogen (N) deficiency is one of the critical environmental factors that induce leaf senescence, and its occurrence may cause the shorten leaf photosynthetic period and markedly lowered grain yield. However, the physiological metabolism underlying N deficiency-induced leaf senescence and its relationship with the abscisic acid (ABA) concentration and reactive oxygen species (ROS) burst in leaf tissues are not well understood. In this paper, the effect of N supply on several senescence-related physiological parameters and its relation to the temporal patterns of ABA concentration and ROS accumulation during leaf senescence were investigated using the premature senescence of flag leaf mutant rice (psf) and its wild type under three N treatments. The results showed that N deficiency hastened the initiation and progression of leaf senescence, and this occurrence was closely associated with the upregulated expression of 9-cis-epoxycarotenoiddioxygenase genes (NCEDs) and with the downregulated expression of two ABA 8′-hydroxylase isoform genes (ABA8ox2 and ABA8ox3) under LN treatment. Contrarily, HN supply delayed the initiation and progression of leaf senescence, concurrently with the suppressed ABA biosynthesis and relatively lower level of ABA concentration in leaf tissues. Exogenous ABA incubation enhanced ROS generation and MDA accumulation in a dose-dependent manner, but it decreased the activities of glutamine synthetase (GS) and glutamate dehydrogenase (GDH) in detached leaf. These results suggested that the participation of ABA in the regulation of ROS generation and N assimilating/remobilizing metabolism in rice leaves was strongly responsible for induction of leaf senescence by N deficiency.

With the tourism industry continuing to boom, the importance of tourism mascots in promoting and publicizing tourism destinations is becoming increasingly prominent. Three core dimensions, market trend, appearance design, and audience feedback, are numerically investigated for deeply iterating tourism mascot design. Further, a subjective and objective evaluation weighting model based on the hierarchical analysis method (AHP) and entropy weighting method is proposed, aiming to utilize the advantages of these methods and ensure the entireness and correctness of results. Taking the mascots of six famous tourist attractions in Xi’an as an example, the feasibility and effectiveness of the evaluation model are verified. Data analysis and modeling results confirm that the three core evaluation indexes of scalability, innovation, and recommendation should be focused on in the design of tourism mascots in the three dimensions of market trends, appearance design, and audience feedback. The evaluation index scores are 0.1235, 0.1170, and 0.1123, respectively, which further illustrates the priority of mascot design. The evaluation model constructed by the research provides decision-makers with a comprehensive evaluation tool from the perspective of tourist experience, and also effectively assists the optimization process of mascot design. In addition, the model has good versatility and adaptability in structural design and evaluation logic and can be widely used in the optimization and evaluation research of brand mascots.

Asymmetry of product–service systems, that is, the presentation of services that does not match the expectations of stakeholders, often leads to inefficient services. To address design asymmetry in service systems, this study proposes a stakeholder-centric methodology for failure touchpoint identification and service reconfiguration. Grounded in the principles of multi-stakeholder value co-creation, the framework involves a three-phase process: systematic identification of failure-prone touchpoints through tripartite analysis (enterprise, service personnel, and user perspectives), generation of reconfiguration alternatives aligned with prioritized stakeholder requirements, and multi-criteria decision-making to optimize service configuration. The methodology achieves design symmetry by integrating stakeholder evaluations across failure diagnosis, causal analysis, and solution validation phases. A case study on a visitor management system demonstrates significant improvements in service quality (overall score increased from 0.70 to 0.81), validating the approach’s efficacy. This research bridges the gap in existing studies by balancing multi-stakeholder interests, offering a novel contribution to service design literature.

Improving customer satisfaction (CS) is one of the core objectives of product configuration. Therefore, accurately analyzing customer opinions and generating appropriate product configuration schemes according to customer opinions are crucial to the success of product configuration. Online product review is a excellent and reliable customer opinion source. Therefore, this paper proposes a customer satisfaction-oriented product configuration approach based on online product reviews. First, this approach identifies critical requirements and quantifies CS degree by extracting and quantifying key elements in online product reviews. Then, the CS degree of the new component scheme is predicted based on the quantitative Kano model and the CS degree of the existing component schemes. Lastly, the single objective programming model is built to generate the product configuration scheme. The product configuration of a desktop 3D printer is taken as an example to verify the feasibility and effectiveness of the proposed approach. Compared with two approaches of customer data acquisition and customer collaboration, it is proved that this approach can effectively improve the CS degree of product configuration scheme, and significantly save the labor, time and cost of product configuration. This approach provides a novel product configuration approach for enterprises to improve CS and extends the application scope for online product review.

In this study, the differences in reactive oxygen species (ROS) generation and abscisic acid (ABA) accumulation in senescing leaves were investigated by early-senescence-leaf (esl) mutant and its wild type, to clarify the relationship among ABA levels, ROS generation, and NADPH oxidase (Nox) in senescing leaves of rice (Oryza sativa). The temporal expression levels of OsNox isoforms in senescing leaves and their expression patterns in response to ABA treatment were determined through quantitative real-time reverse transcription PCR (qRT-PCR). Results showed that the flag leaf of the esl mutant generated more O2- concentrations and accumulated higher ABA levels than the wild-type cultivar did in the grain-filling stage. Exogenous ABA treatment induced O2- generation; however, it was depressed by diphenyleneiodonium chloride (DPI) pretreatment in the detached leaf segments. This finding suggested the involvement of NADPH oxidase in ABA-induced O2- generation. The esl mutant exhibited significantly higher expression of OsNox2, OsNox5, OsNox6, and OsNox7 in the initial of grain-filling stage, followed by sharply decrease. The transcriptional levels of OsNox1, OsNox3, and OsFR07 in the flag leaf of the esl mutant were significantly lower than those in the wild-type cultivar. The expression levels of OsNox2, OsNox5, OsNox6, and OsNox7 were significantly enhanced by exogenous ABA treatments. The enhanced expression levels of OsNox2 and OsNox6 were dependent on the duration of ABA treatment. The inducible expression levels of OsNox5 and OsNox7 were dependent on ABA concentrations. By contrast, exogenous ABA treatment severely repressed the transcripts of OsNox1, OsNox3, and OsFR07 in the detached leaf segments. Therefore, OsNox2, OsNox5, OsNox6, and OsNox7 were probably involved in the ABA-induced O2- generation in the initial stage of leaf senescence. Subsequently, other oxidases activated in deteriorating cells were associated with ROS generation and accumulation in the senescing leaves of the esl mutant. Conversely, OsNox1, OsNox3, and OsFR07 were not associated with ABA-induced O2- generation during leaf senescence.

To clarify the relationship of sugar starvation with ABA-induced ROS generation during leaf senescence, the genotype-dependent differences in sugar concentration, endogenous ABA content, and ROS generation as well as their temporal patterns during leaf senescence were investigated by using two rice genotypes, namely, Zhehui7954 and its corresponding mutant with the premature senescence of flag leaves (psf). Meanwhile, the interplay between sugar starvation and ABA metabolism in the induction of leaf senescence was examined using detached leaves. The results showed that the psf mutant differed evidently from its wild type (Zhehui7954) in the temporal pattern of soluble sugar, sucrose and hexose (fructose and glucose) contents during leaf senescence, with the rapidly dropping concentrations of total soluble sugar, and sucrose, and hexose for the senescing leaves of psf mutant. Sugar starvation evidently accelerated leaf senescence and significantly enhanced the ABA concentration and malonaldehyde (MDA) accumulation in detached leaves, while exogenous sugar supply severely suppressed the ABA concentration and ROS level in detached leaves, thereby the delayed leaf senescence for the detached leaves treated by exogenous sugar supply. Correspondingly, ABA biosynthesis inhibitor (NDGA) effectively retarded the sugar starvation-induced leaf senescence, while ABA catabolism inhibitor (DNCZ) obviously accelerated leaf senescence by enhancing the endogenous ABA concentration in senescent leaves. Furthermore, sugar starvation severely repressed the transcripts of several key genes related to ABA biosynthesis and its degradation (NCED1, NCED4, NCED5, ABA8ox2 and ABA8ox3), with the significantly lower amount of their transcriptional expression in the senescent leaves of psf mutant relative to its wild type during leaf senescence. Hence, the disequilibrium between ABA biosynthesis and catabolism was strongly responsible for sugar starvation-induced leaf senescence, which was derived from the suppression of ABA degradation, rather than the enhancement of ABA biosynthesis.

The translocation of nonstructural carbohydrates (NSC) from leaf sheaths to filling grains after anthesis contributed greatly to the grain yield of cereal crops. In this study, the effect of nitrogen (N) supply levels on the accumulation and translocation of NSC in leaf sheath tissues and its relationship with the initiation and progression of leaf senescence during grain filling was investigated using two rice (Oryza sativa L.) genotypes, namely, premature flag leaf senescence mutant (psf) and its wild‐type. Three N treatment levels were used to examine N‐supply induced alteration in the activities of several key enzymes involved in NSC translocation and N assimilation in different leaf sheaths. The results show that the NSC translocation rate in leaf sheaths under low nitrogen (LN) treatment was significantly higher than those under normal nitrogen (NN) and high nitrogen (HN) treatments. However, the positive effect of LN on the NSC translocation in leaf sheath was closely associated with its negative effect on grain yield, due to accelerated leaf senescence and shortened leaf longevity. Comparatively, the upper‐positional sheath had a lower NSC amount and higher NSC translocation rate than the lower‐leaf sheaths after heading. High N suppressed sucrose‐phosphate synthase (SPS) activity in leaf sheaths, but enhanced the activity of key enzymes involving in N assimilation in leaf sheaths. The upper sheath had higher activity of sucrose‐metabolizing enzymes and lower activity of N‐assimilating enzymes. Hence, the upper‐leaf sheath had a relatively weak N assimilation and stronger NSC translocation than the lower‐leaf sheaths.

D1 protein in the PSII reaction center is the major target of photodamage, and it exhibits the highest turnover rate among all the thylakoid proteins. In this paper, rice psf (premature senescence of flag leaves) mutant and its wild type were used to investigate the genotype-dependent alteration in PSII photo-damage and D1 protein turnover during leaf senescence and its relation to ABA accumulation in senescent leaves. The symptom and extent of leaf senescence of the psf mutant appeared to be sunlight-dependent under natural field condition. The psf also displayed significantly higher levels of ABA accumulation in senescent leaves than the wild type. However, the premature senescence lesion of psf leaves could be alleviated by shaded treatment, concomitantly with the strikingly suppressed ABA level in the shaded areas of flag leaves. The change in ABA concentration contributed to the regulation of shade-delayed leaf senescence. The participation of ABA in the timing of senescence initiation and in the subsequent rate of leaf senescence was closely associated with PSII photodamage and D1 protein turnover during leaf senescence, in which the transcriptional expression of several key genes (psbA, psbB, psbC and OsFtsH2) involved in D1 protein biosynthesis and PSII repair cycle was seriously suppressed by the significantly increased ABA level. This response resulted in the low rate of D1 protein synthesis and impaired repair recovery in the presence of ABA. The psf showed evidently decreased D1 protein amount in the senescent leaves. Both the inhibition of de novo synthesized D1 protein and the slow rate of proteolytic removal for the photodamaged D1 protein was among the most crucial steps for the linkage between light-dependent leaf senescence and the varying ABA concentration in psf mutant leaves. OsFtsH2 transcriptional expression possibly played an important role in the regulation of D1 protein turnover and PSII repair cycle in relation to ABA mediated leaf senescence.

Ambient temperature and nitrogen (N) fertilizer are two of the most important factors that affect rice grain quality. However, less information has been available on the interactive effect of N fertilizer and ambient temperature on grain quality under stressful high temperature (HT). In this article, the effects of panicle N fertilizer, ambient temperature, and their interaction on starch composition, particle size distribution of starch granules, starch physicochemical properties, and storage protein accumulation in milled grains were investigated to clarify the potential role of panicle N fertilizer topdressing in regulating rice grain quality under stressful HT by using a two-factor experiment of three N levels in combination with two temperature regimes. Results showed that appropriate application of panicle N fertilizer could attenuate the adverse effect of HT during grain filling on milling quality and chalky occurrence to some extent, particularly for the effective alleviation of HT-induced decrease in milling quality. However, the topdressing of panicle N fertilizer tended to enhance starch gelatinization enthalpy (ΔH) and its setback viscosity in HT-ripening grains, with the simultaneous decrements in the number and surface area proportions of smaller starch granules under the higher N fertilizer in combination with HT exposure. The effects of higher nitrogen fertilizer and HT exposure on total protein content and gluten composition of grains were additively increased. Hence, the topdressing of panicle N fertilizer exacerbated HT-induced deterioration in cooking and eating quality, rather than alleviating the negative impact of HT exposure on the palatability of cooked rice.

Effect of high temperature (HT) on anthocyanin (ANS) accumulation and its relationship with reactive oxygen species (ROS) generation in color rice kernel was investigated by using a black kernel mutant (9311bk) and its wildtype (WT). 9311bk showed strikingly higher ANS content in the kernel than WT. Just like the starch accumulation in rice kernels, ANS accumulation in the 9311bk kernel increased progressively along with kernel development, with the highest level of ANS at kernel maturity. HT exposure evidently decreased ANS accumulation in 9311bk kernel, but it increased ROS and MDA concentrations. The extent of HT-induced decline in kernel starch accumulation was genotype-dependent, which was much larger for WT than 9311bk. Under HT exposure, 9311bk had a relatively lower increase in ROS and MDA contents than its WT. This occurrence was just opposite to the genotype-dependent alteration in the activities of antioxidant enzymes (SOD, CAT and APX) in response to HT exposure, suggesting more efficiently ROS detoxification and relatively stronger heat tolerance for 9311bk than its WT. Hence, the extent of HT-induced declines in grain weight and kernel starch content was much smaller for 9311bk relative to its WT. HT exposure suppressed the transcripts of OsCHS, OsF3’H, OsDFR and OsANS and impaired the ANS biosynthesis in rice kernel, which was strongly responsible for HT-induced decline in the accumulation of ANS, C3G, and P3G in 9311bk kernels. These results could provide valuable information to cope with global warming and achieving high quality for color rice production.