Low solar radiation, caused by climate change or dense planting patterns, now limits wheat production. Although wheat breeding has increased lodging resistance and yield potential through the introduction of dwarfing genes, it still reduces wheat yields. Few studies have been conducted to clarify the lodging sensitivity to shading of different-era wheat cultivars in China’s Huang-Huai-Hai region, as well as the characteristics of lodging resistance as affected by paclobutrazol under shading stress. To address this gap, the experiment included two wheat cultivars released in different decades, grown under shade and treated with or without paclobutrazol. The results showed that reductions in filling degree and lignin content, together with increases in length of the basal internode and gravity center height, markedly reduced the section modulus and breaking strength of shaded wheat culms. These changes impaired lodging resistance and raised lodging risk. However, paclobutrazol application effectively reduced lodging incidence and increased wheat yield under shading stress. Furthermore, these responses were more pronounced in the old cultivar (YZM) than in the modern cultivar (S28). This indicates that the culm mechanical parameters of the old cultivar were more shade-sensitive than those of the modern cultivar. Moreover, shading downregulated the relative expression levels of key genes associated with lignin biosynthesis to decrease the activities of key enzymes, thereby inhibiting the biosynthesis and deposition of lignin in culms to increase the risk of wheat lodging. Paclobutrazol application alleviated the inhibitory effects of shading on lignin biosynthesis, thereby strengthening culms and enhancing lodging resistance. These findings may provide a basis for exploring cultivation regulation methods to enhance wheat lodging resistance under overcast and low-sunshine conditions, and to offer guidance for the breeding of wheat cultivars with lodging resistance and shade tolerance.

Elevated temperatures due to global climate change adversely affect plant growth and development, which has become a major factor restricting wheat (Triticum aestivum L.) production. Despite the introduction of dwarfing genes that have enhanced lodging resistance as well as productive potential in wheat breeding, lodging still affects wheat yields. Plant growth regulators are widely recognized as effective agents in mitigating crop lodging. Few studies have investigated the high-temperature lodging sensitivity of wheat genotypes from different breeding periods, nor have they examined how uniconazole-sucrose regulates lodging resistance under heat stress. To fill this research gap, an experiment was conducted in which two contrasting wheat genotypes from different periods, Bima 1 (BM1, ~135 cm tall, a historical genotype released in 1953, lodging-susceptible) and Shannong 28 (S28, ~75 cm tall, a modern genotype released in 2014, lodging-resistant), were exposed to high temperature stress combined with uniconazole-sucrose application. The results showed that high-temperature-induced increases in plant gravity center height, together with decreased stem diameter coefficient, stem plumpness, and lignin deposition, were the main factors responsible for the reduction in bending section factor and mechanical strength of wheat stems. These modifications are associated with reduced lodging resistance, increased susceptibility to lodging, and significant yield losses. Nevertheless, exogenous application of uniconazole-sucrose lowers plant gravity center height, enhances stem diameter coefficient, stem plumpness, and lignin content, thus alleviating lodging risk and boosting wheat yield under high temperature stress. High temperature stress was associated with downregulated relative expression levels of key genes involved in lignin metabolism and reduced activities of the corresponding key enzymes, as well as inhibited lignin biosynthesis and accumulation in stems and increased incidence of wheat lodging. Conversely, foliar spraying of uniconazole-sucrose alleviated these suppressive effects on lignin biosynthesis, thus enhancing stem mechanical strength and reducing the lodging index of wheat. Moreover, these indicators were more sensitive to heat stress or uniconazole-sucrose treatment in BM1. The two genotypes examined suggested a potential trend that S28 may exhibit reduced sensitivity to high temperature in terms of mechanical traits and lignin synthesis, which could contribute to enhanced lodging resistance under heat stress.

Mature-green tomatoes are prone to rapid ripening and quality deterioration during the postharvest stage, highlighting the urgent need for environmentally friendly and efficient preservation technologies. This study investigated the synergistic regulatory effects of nano-SiO₂ and light quality (white light, W; blue light, B; red/blue mixed light, RB, 1:1) on postharvest appearance, physiological processes, and quality attributes in ‘Yu Zhu’ (Solanum lycopersicum L.), a tasty tomato cultivar with light-yellow fruit color. Mature-green fruits were treated with light quality in combination with nano-SiO₂ (pre-immersion in 1 mL/L nano-SiO₂ for 1 h, followed by periodic spraying with 0.5 mL/L nano-SiO₂ every two days). Key indicators—including ripening traits, flavor attributes, antioxidant capacity, and endogenous hormone metabolites—were monitored on their respective sampling days. The results revealed distinct light quality-dependent responses: (1) B-Si (B + nano-SiO₂) significantly delayed the breaker stage compared to W, maintained the lowest water loss, and exhibited the slowest softening rate. W-Si showed a significantly higher dry weight-to-fresh weight ratio than W. (2) RB-Si achieved superior flavor quality, with 11.47% soluble solids, 1.62% titratable acidity, and a sugar-to-acid ratio of 7.2—values markedly higher than those in RB. (3) RB-Si increased total phenolic (TP), flavonoids, and ascorbic acid (AsA) levels relative to RB, while enhancing total antioxidant capacity (T-AOC) and the activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), with only slight suppression of ascorbate peroxidase (APX) activity. (4) Nano-SiO₂ differentially regulated hormonal metabolism depending on light quality: it activated the jasmonic acid (JA)–gibberellin (GA) pathway under W light, fine-tuned cytokinin (CK) metabolism under B light, and upregulated JA, GA, CK, and auxin under RB light. Moreover, RB-Si significantly reduced ACC accumulation compared to W, thereby delaying senescence. Collectively, RB-Si synergistically regulates endogenous hormone metabolism to simultaneously delay ripening, reduce water loss, maintain firmness, optimize flavor, and enhance antioxidant capacity. This study elucidates the interaction mechanism between nano-SiO₂ and light quality, providing theoretical and technical support for the green preservation of horticultural crops.

Light quality and light intensity, as important environmental signals, can regulate the ripening process and flavor compound synthesis in tomato fruits. Chitosan oligosaccharides, as natural bio-stimulants, can improve postharvest quality of fruits and vegetables. However, how varied LED light quality–intensity regimes modulate ripening and aroma metabolism in chitosan-oligosaccharide-pre-treated mature-green tomato fruit remains unclear. This study used mature-green tomato fruits as experimental material, which were pre-treated by immersion in chitosan oligosaccharide solution. Subsequently, different combinations of supplemental light qualities (white light, blue light, and 1:1 red–blue composite light) and varying light intensities were applied for continuous illumination. The effects of these lighting conditions on the postharvest physiological quality and volatile aroma components of tomatoes were systematically investigated, and the molecular regulatory mechanisms were analyzed through transcriptome sequencing. The results showed that light quality and intensity significantly regulated tomato fruit color change, firmness, pigment accumulation, and sugar–acid quality. High-intensity red–blue combined light treatment (RB-H) effectively accelerated fruit ripening, promoted carotenoid accumulation, significantly increased the content of terpenes and aromatic volatile compounds, and improved fruit flavor. Transcriptome analysis revealed that different light treatments induced a large number of differentially expressed genes, with transcription factors from the WRKY, MYB, AP2/ERF, bHLH, NAC, and C2H2 families widely involved in light signal responses. Weighted gene co-expression network analysis (WGCNA) identified two key modules associated with light response. KEGG pathway enrichment analysis revealed that the biosynthesis of the terpenoid backbone, monoterpenoid biosynthesis, sesquiterpenoid and triterpenoid biosynthesis, as well as tyrosine metabolism pathways, are the core pathways regulating the production of volatile aroma compounds in tomatoes. In summary, RB-H treatment promotes the accumulation of characteristic aromatic compounds and enhances overall tomato quality by activating key genes involved in terpenoid biosynthesis and tyrosine metabolism pathways. This study reveals the transcriptional regulatory network by which light quality and intensity shape postharvest tomato ripening and flavor development in chitosan-oligosaccharide-pre-treated fruit, providing theoretical support for precise LED light environment control and targeted improvement of flavor quality in postharvest tomatoes.

Lodging is a major constraint limiting wheat (Triticum aestivum L.) yield and quality globally. Despite dwarfing genes reducing plant height and mitigating lodging risk and losses, lodging still severely limits wheat yield. Few studies have examined how wheat breeding has altered the sensitivity of yield to lodging, especially its penalties in grain number and grain weight at specific spike positions. Two separate experiments were conducted in the Huang-Huai-Hai region of China: a lodging-period experiment (two genotypes, five periods) during the 2011–2013 growing seasons, and a lodging-angle experiment (three genotypes, five angles) during the 2019–2021 growing seasons. The results showed that grain number per m² (GNO), average grain weight (AGW), and grain yield (GY) all increased linearly with genotype release year. Lodging significantly reduced GNO and AGW, and consequently GY in all genotypes, but these losses declined linearly with the year of genotype release, indicating that modern genotypes suffer less yield penalty under lodging. Furthermore, lodging at any stage reduced the weight of both superior and inferior grains within the spike, whereas only pre-anthesis lodging decreased grain number per spike. Inferior grains, owing to their higher environmental sensitivity, showed larger reductions in both grain number and grain weight per spike than superior grains. Across all genotypes, lodging decreased grain number and grain weight per spike in the order apical > basal > central, and the relative losses declined linearly with year of genotype release. Moreover, lodging-induced losses in ¹³C assimilation followed the order old > intermediate > modern across genotype eras; the reduction in ¹³C assimilation within the spike ranked apical > basal > central, and that in superior grains exhibited the same pattern. Concurrently, the allocation of ¹³C assimilates to inferior grains was markedly inhibited across all spike positions, with the reduction magnitude significantly exceeding that in superior grains. Lodging-induced differential changes in ¹³C assimilation among grain positions within each spike layer are associated with the uneven reductions in grain number and average grain weight across the spike. These findings may provide a basis for lodging-resistant wheat production and cultivar breeding. Artificial lodging induction can serve as a reliable strategy to efficiently evaluate yield stability and lodging tolerance. However, its applicability to other wheat regions needs further verification via multi-location and multi-cultivar trials.