Ananas comosus var. bracteatus (Ac. bracteatus) is a typical leaf-chimeric ornamental plant. The chimeric leaves are composed of central green photosynthetic tissue (GT) and marginal albino tissue (AT). The mosaic existence of GT and AT makes the chimeric leaves an ideal material for the study of the synergistic mechanism of photosynthesis and antioxidant metabolism. The daily changes in net photosynthetic rate (NPR) and stomatal conductance (SCT) of the leaves indicated the typical crassulacean acid metabolism (CAM) characteristic of Ac. bracteatus. Both the GT and AT of chimeric leaves fixed CO₂ during the night and released CO₂ from malic acid for photosynthesis during the daytime. The malic acid content and NADPH-ME activity of the AT during the night was significantly higher than that of GT, which suggests that the AT may work as a CO₂ pool to store CO₂ during the night and supply CO₂ for photosynthesis in the GT during the daytime. Furthermore, the soluble sugar content (SSC) in the AT was significantly lower than that of GT, while the starch content (SC) of the AT was apparently higher than that of GT, indicating that AT was inefficient in photosynthesis but may function as a photosynthate sink to help the GT maintain high photosynthesis activity. Additionally, the AT maintained peroxide balance by enhancing the non-enzymatic antioxidant system and antioxidant enzyme system to avoid antioxidant damage. The enzyme activities of reductive ascorbic acid (AsA) and the glutathione (GSH) cycle (except DHAR) and superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were enhanced, apparently to make the AT grow normally. This study indicates that, although the AT of the chimeric leaves was inefficient at photosynthesis because of the lack of chlorophyll, it can cooperate with the GT by working as a CO₂ supplier and photosynthate store to enhance the photosynthetic ability of GT to help chimeric plants grow well. Additionally, the AT can avoid peroxide damage caused by the lack of chlorophyll by enhancing the activity of the antioxidant system. The AT plays an active role in the normal growth of the chimeric leaves.

The art of pressed flowers is a method of artistic expression involving the pressing of flowers, leaves, and other plant organs for artistic creative purposes. However, the pressing process often results in color variation of the plant material, which significantly diminishes the quality of artistic works and must be solved using appropriate techniques. During this research, phenylalanine (10 mmol⋅L ⁻¹ ) was used to treat the petals of postharvest Petunia flowers to investigate the impact of phenylalanine on mitigating color variation, and the effect of phenylalanine on inhibiting the color variation of Petunia petals during the pressing process was evaluated by color measurement, physicochemical indices, and gene expression level analyses. Using the CIE L*a*b* color measurements, the samples from the test group had significantly higher brightness ( L* ) and red coloration ( a* ) at the final stage (S4) than the control group. In addition, phenylalanine had a significant inhibitory effect on malondialdehyde and superoxide anion accumulations in Petunia petals during pressing and reduced the enzymatic activities of superoxide dismutase, polyphenol oxidase, and catalase. The quantitative reverse-transcription polymerase chain reaction analysis showed that the transcript levels of CHS , DFR , F3′5′H , and UFGT genes in the petals of the treatment group continued to increase during the pressing process, and the transcript levels of key genes in the anthocyanin metabolic pathway of the treated samples were higher than those of the control group at the final stage (S4). These results indicated that phenylalanine can effectively diminish the color variation of Petunia petals in the pressing process, which could serve as a theoretical basis for the development of a comprehensive technology system aimed at preserving the color of pressed horticultural plants.