Non-heading Chinese cabbage (cabbage) is an essential green leafy vegetable, and bolting and flowering are necessary for reproduction. However, further research is needed to study the effect of photoperiod on the bolting and flowering of cabbage, particularly on the development of the stem. In this study, we performed phenotypic analysis and measured endogenous gibberellin levels in the cabbage. We carried out these experiments under four different photoperiodic treatments, 12 h (light)/12 h (dark), 14 h (light)/10 h (dark), 16 h (light)/8 h (dark), and 18 h (light)/6 h (dark). The results showed that the time of bolting and flowering gradually decreased with increasing light duration. The development of stems was optimal under the 16 h (light)/8 h (dark) photoperiod treatment, and the same result was obtained via cytological observation. In addition, the changes in the endogenous gibberellin3 (GA₃) content under different photoperiodic treatments were consistent with the development of stems and peaked at 16 h (light)/8 h (dark). At the same time, qRT-PCR analysis showed that the relative expression of the key gibberellin synthase genes, BcGA3ox2 and BcGA20ox2, exhibited upregulation. When treated with exogenous GA₃ and its synthesis inhibitor, paclobutrazol (PAC), exogenous gibberellins significantly promoted bolting; conversely, gibberellin inhibitors suppressed the bolting, flowering, and stem elongation of cabbage. Therefore, the photoperiod may regulate cabbage bolting by regulating endogenous GA₃.

Nickel (Ni) is an essential trace element for plant growth and a component of the plant body that has many different functions in plants. Although it has been confirmed that nickel ions (Ni²⁺) havea certain regulatory effect on nitrogen (N) metabolism, there are not enough data to prove whether exogenous Ni²⁺ can increase the carbon (C) and N metabolism in the roots of tomato seedlingsunder low-nitrogen (LN) conditions. Therefore, through the present experiment, we revealed the key mechanism of Ni²⁺-mediated tomato root tolerance to LN levels. Tomato plants were cultured at two different N levels (7.66 and 0.383 mmol L⁻¹) and two different Ni²⁺ levels (0 and 0.1 mg L⁻¹ NiSO₄ 6H₂O) under hydroponic conditions. After nine days, we collected roots for physiological, biochemical, and transcriptome sequencing analyses and found that the activities of N assimilation-related enzymes decreased at LN levels. In contrast, Ni²⁺ significantly increased the activities of N assimilation-related enzymes and increased the contents of nitrate (NO₃⁻), ammonium (NH₄⁺), and total amino acids. Through root transcriptomic analysis, 3738 differentially expressed genes (DEGs) were identified. DEGs related to C and N metabolism were downregulated after LN application. However, after Ni²⁺ treatment, PK, PDHB, GAPDH, NR, NiR, GS, GOGAT, and other DEGs related to C and N metabolism were significantly upregulated. In conclusion, our results suggest that Ni²⁺ can regulate the C and N metabolism pathways in tomato roots to alleviate the impact of LN levels.

Cucumber (Cucumis sativus L.) lateral branch elongation is influenced by a variety of environmental signals, including light [e.g., far-red (FR) light] and hormones. In this experiment, the effect of FR light on the lateral branch elongation of cucumber (‘Zhongnong No. 26’) seedlings was investigated. The results showed that FR light significantly inhibited the lateral branch elongation of cucumber seedlings. In addition, FR light significantly increased the auxin (indole-3-acetic acid, IAA) content, decreased the cytokinin (CTK; Zeatin) content, and suppressed the expression of most CTK synthetic-related genes, such as IPTs, in cucumber seedlings. The lateral branch elongation of cucumber seedlings was assessed in response to decapitation and exogenous 6-BA treatment to further investigate the relationship between IAA and CTK on the lateral branch elongation of cucumber seedlings under FR light. Both decapitation and exogenous 6-BA treatment eliminated the inhibitory effect of FR light on the lateral branch elongation of cucumber seedlings. In conclusion, these results indicated that IAA and CTK were involved in the regulatory effects of FR light on cucumber seedling lateral branch elongation.

Rice is central to global food security, and plant factories enable precise control of lighting conditions. However, genotype-specific responses to supplemental blue light across the full crop cycle remain poorly understood. Here, Nipponbare and CP511 were grown from transplanting to maturity under a green, red, and far-red background supplemented with 0, 50, 100, 150, or 300 μmol m⁻² s⁻¹ blue light (B0–B300). In both genotypes, increasing supplementation reduced plant height, increased tillering and biomass, advanced flowering by 9–13 d, and enhanced pigment content and photosynthetic capacity. Nipponbare maintained photosynthetic improvements at higher supplementation levels, whereas CP511 plateaued earlier. In Nipponbare, grain yield increased from 1.46 g plant⁻¹ at B0 to 5.09 g plant⁻¹ at B100 but did not increase significantly thereafter, despite enhanced photosynthesis and sucrose metabolism. At B300, seed setting declined to 54%, with reduced dry-matter allocation to panicles. In CP511, higher supplementation increased total panicle production but not effective panicle formation, seed setting, or grain yield, which changed from 3.29 g plant⁻¹ at B150 to 2.49 g plant⁻¹ at B300. Thus, the most favorable treatment depended on coordination between source capacity and effective reproductive sink formation rather than maximal photosynthesis or panicle production alone.

The ratio of red to far-red (FR) light (the R/FR ratio) is a core signal regulating shade-induced internode elongation in plants, but the underlying mechanism in cucumber remains not fully elucidated. Therefore, in the present study, cucumber (Cucumis sativus L. ‘Zhongnong No. 26′) was used as the material, and through a combination of physiological, transcriptomic, and proteomic analyses, we investigated the mechanism underlying internode elongation via R/FR ratio in cucumber plants. Low R/FR ratio significantly promoted cucumber seedling internode elongation by enhancing the longitudinal growth of internode cells. Hormonal profiling decreased the contents of indole-3-acetic acid (IAA), salicylic acid (SA), cytokinin (CTK; tZR, T-zeatin, and iPR), and ethylene (Eth), whereas jasmonic acid (JA) and gibberellin (GA) contents were elevated in cucumber seedling internodes. Bioinformatics analysis revealed that low R/FR ratio upregulated GA biosynthesis-related genes (KAO, GA20ox), and the expression of genes/proteins encoding cell wall remodeling/biosynthesis enzymes (EXP, XTH and CesA), and aquaporin proteins (AQPs). Exogenous GA4/7 mimicked the promotive effect of low R/FR on internode elongation under white light, while the GA biosynthesis inhibitor paclobutrazol (PAC) reversed this response, confirming a central role for GA in this process. These results reveal the crucial role of cell wall biosynthesis and hormone metabolism-related genes/proteins in low R/FR ratio-induced cucumber internode elongation. Such work may further elucidate the evolutionary and agronomic trade-offs associated with shade avoidance and provide a basis for optimizing canopy architecture and light management in cucumber cultivation.

Photosynthetic carbon assimilation under photorespiratory conditions requires tight coordination between chloroplast electron transport and mitochondrial redox metabolism, yet the contribution of mitochondrial alternative oxidase (AOX) remains unresolved. Using 1 mM salicylhydroxamic acid (SHAM) to inhibit the AOX pathway in Rumex K-1 leaves, we investigated how mitochondrial alternative respiration contributes to carbon assimilation. AOX inhibition imposed a non-stomatal limitation on CO₂ assimilation and reduced photosystem II (PSII) electron transport. However, low O₂ or elevated CO₂ alleviated the decline in CO₂ assimilation while PSII photochemistry remained depressed, and AOX inhibition reduced apparent V_cmax without significantly affecting J_max, indicating that the primary constraint lay downstream of PSII in photorespiratory carbon metabolism. Electron flux through PSII and the electron fluxes supporting the photosynthetic carbon reduction and photorespiratory carbon oxidation cycles all decreased under SHAM treatment, indicating reduced PSII electron transport and electron use associated with carbon assimilation and photorespiration. AOX inhibition caused glycine accumulation and increased the Gly/Ser ratio under illumination but not in darkness, indicating restricted mitochondrial glycine-to-serine conversion during photorespiration. Together, these responses suggest that AOX-dependent ubiquinol oxidation helps sustain mitochondrial NADH reoxidation and NAD⁺ regeneration, thereby supporting glycine-to-serine conversion and photorespiratory carbon recycling.