(1) Background: To solve the problems of incomplete coloration and quality decline caused by unreasonable use of regulators in grapes, this study clarified the differences in the effects of a hormone-type growth regulator (AUT) and two commercial regulators on grape coloration and quality through field experiments. (2) Methods: The color indexes (brightness (L*), red/green color difference (a*), yellow/blue color difference (b*), and color index for red grapes (CIRG)) of grape fruit were measured using a CR-400 handheld color difference meter. The titratable acid content, total phenol content, and total sugar content were measured using anthrone colorimetry, folinol colorimetry, and NaOH titration, respectively, and the chalcone isomerase activity, phenylalanine ammoniase activity, dihydroflavol reductase activity, and anthocyanin content were measured using a UV spectrophotometer. (3) Results: The a*, total sugar and total phenol contents, and chalcone isomerase (CHI) and phenylalanine ammoniase (PAL) activities of grape fruit in the AUT treatment significantly increased, while the titratable acid content significantly decreased, compared to those in the CK treatment. The expressions of the differentially expressed genes (DEGs) trpB and argJ in AUT treatment were significantly up-regulated. The expressions of the differentially expressed metabolites (DEMs) phenylalanine and 4-oxoproline were significantly up-regulated, while those of 3,4-dihydroxybenzaldehyde and N-acetyl glutamate were significantly down-regulated. The CIRG significantly increased by 36.4% compared to that in the CK, indicating improved fruit coloration. (4) Conclusion: The AUT could shorten the color conversion period of grape fruit and improve the coloration, taste, and tolerance to saline and alkaline stresses.

In recent years, there have been many studies on the response of plants to heavy metal stress, but the metabolic changes in bryophytes, pioneer plants quickly responding to environmental changes, under exogenous cadmium (Cd) stress have yet to be explored. In this indoor experiment, the responses in the metabolome of bryophyte Tortella tortuosa (Hedw.) Limpr. to different Cd exposure levels (0 (CK), 5 (T1), and 10 (T2) mg·L⁻¹) were analyzed. The results showed that the number of differentially accumulated metabolites (DAMs) secreted by T. tortuosa increased with the increase in the Cd concentration, and the biosynthesis of cofactors, D-Amino acid metabolism, Arginine biosynthesis, ATP-binding cassette transporters (ABC transporters), and biosynthesis of alkaloids derived from shikimate pathway were the main pathways enriched by DAMs. The relative abundances of malic acid, N-Formylkynurenine, L-Glutamine, L-Histidine, LL-2,6-Diaminopimelic acid, and fusaric acid in the T2 treatment increased by 16.06%, 62.51%, 14.51%, 11.92%, 21.37%, and 35.79%, respectively (p < 0.05), compared with those of the CK, and the correlation analysis results showed that the above DAMs were closely related to the changes in plant antioxidant enzyme activity and Cd concentration. These results indicate that the secretion of amino acid (N-Formylkynurenine, L-Histidine) and organic acids (isocitric acid, LL-2,6-Diaminopimelic acid, malic acid) through the metabolic pathways, including biosynthesis of amino acids, biosynthesis of cofactors, glyoxylate and dicarboxylate metabolism, and ABC transporters, is the metabolic mechanism of T. tortuosa to resist exogenous Cd stress. This study will provide a reference for the monitoring and remediation of heavy metal pollution.

Soil salinization and alkalization can cause great losses to agricultural production in arid regions. Cotton, a common crop in arid and semi-arid regions in China, often encounters saline stress and alkaline stress. In this study, NaCl (8 g·kg⁻¹), Na₂CO₃ (8 g·kg⁻¹⁾, and a compound material (an organic polymer compound material) were mixed with field soil before cotton sowing, and the ion content, photosynthetic characteristics, and metabolite levels of the new cotton leaves were analyzed at the flowering and boll-forming stage, aiming to clarify the photosynthetic and metabolic mechanisms by which compound material regulates cotton’s tolerance to saline stress and alkaline stress. The results showed that the application of the compound material led to an increase in the K⁺/Na⁺ ratio, stomatal conductance (Gs), efficiency of PSII photochemistry (ψPSⅡ), potential activity (Fv/Fo), and chlorophyll content (Chla and Chlb), as well as the abundances of D-xylonic acid and DL-phenylalanine in the NaCl treatments. Additionally, there were increases in the K⁺ content, K⁺/Na⁺ ratio, Chla/b ratio, net photosynthetic rate (Pn), transpiration rate (Tr), ψPSⅡ, and D-saccharic acid abundance in the Na₂CO₃ treatments. A correlation analysis and a metabolic pathway analysis revealed that the compound material mainly regulated the photosynthetic characteristics of and the ion balance in the new leaves through regulating the abundance of key metabolites when the cotton was under NaCl stress or Na₂CO₃ stress. Furthermore, the positive impact of the compound material on the cotton’s NaCl stress tolerance was stronger than that on the cotton’s Na₂CO₃ stress tolerance.

Apple (Malus domestica) is one of the most widely cultivated and consumed fruits worldwide, valued for its rich nutrition and health benefits. Low temperature (LT) significantly limits apple growth, productivity, and fruit quality. Understanding the intricate regulatory networks, underlying cold tolerance is crucial for developing resilient apple cultivars. In this review, we comprehensively summarize the molecular control enabling apple to withstand cold stress, encompassing transcription cascades, phytohormonal networks, reactive oxygen species (ROS) regulation, epigenetic modifications, and post-translational modifications (PTMs), as well as the crosstalk with drought, immune, and light signaling pathways. We also discuss the management strategies for enhancing apple cold tolerance, including the exploitation of wild germplasm resources, multi-omics-based network integration, gene editing, molecular marker-assisted breeding, rootstock grafting, and emerging bioinoculants approaches. This review provides a foundational framework for molecular breeding and gene regulatory strategies to improve cold resilience in apple.