Crocins are valuable bioactive components of gardenia fruit, and their biosynthesis and accumulation have attracted widespread interest. Studies have investigated the biosynthesis and accumulation of crocin based on Illumina sequencing, but there is a lack of reports based on full-length transcriptome sequencing. Utilising SMRT sequencing and high-performance liquid chromatography (HPLC), we explored crocin biosynthesis and accumulation in the fruit of Gardenia jasminoides. HPLC analysis showed that crocins specifically exist in fruit and that the content of crocins increases gradually during fruit development. SMRT sequencing generated 46,715 high-quality full-length isoforms, including 5230 novel isoforms that are not present in the G. jasminoides genome. Furthermore, a total of 46 genes and 91 lncRNAs were involved in the biosynthesis and accumulation of crocin. The qRT-PCR indicated that genes involved in crocin biosynthesis reached a peak in the NOV stage. These findings contributed to our understanding of crocin biosynthesis and accumulation.

To investigate the effect of genotype–environment interaction (GEI) on Gardenia jasminoides crocin contents, this study combined the additive main effects and multiplicative interactions (AMMI) model and genotype × environment interaction (GGE) biplot method to investigate the adaptation and stability of 11 Gardenia jasminoides genotypes at three experimental sites in Jiangxi Province with replications. The AMMI analysis showed that genotype, environment, and the GEI had extremely significant effects on Gardenia jasminoides crocin contents (p < .001). The GEI was the main factor causing the content variation, followed by genotype. The AMMI model and biplot analysis showed that the HC20 genotype had high and stable crocin contents. The GGE biplot analysis showed that Fengcheng and Gongqingcheng were optimal test sites for the selection of Gardenia jasminoides genotypes based on their crocin contents; additionally, the HC20 genotype was a suitable dominant genotype to promote cultivation in the test areas, and the GY8 genotype could be widely planted in the Gongqingcheng area. Therefore, the AMMI and GGE biplot genotype evaluation results were basically consistent. Comprehensive and effective evaluation of genotype and regional test sites can provide a theoretical basis for the breeding and development of Gardenia jasminoides clones with high and stable crocin contents and the selection of test sites.

Pinus massoniana is a critical afforestation and ecological tree species in China. However, the continued existence of this pine is severely threatened by pine wilt disease. Somatic embryogenesis serves as a highly efficient clonal propagation approach. Although significant progress has been made in somatic embryogensis research on P. massoniana, resulting in the successful regeneration of plants, the limited embryogenic potential of improved cell lines and loss of embryogenic properties resulting from prolonged proliferation have posed obstacles to the industrialization of SE production. In this study, we investigated the effect of phytosulfokine on embryo development of cell lines from P. massoniana which lead to a cascade of physicochemical changes. Eight embryogenic cell lines of P. massoniana were used to observe phenotype and cytological changes. Physiological factors and the contents of nutrients and endogenous hormones were measured before and after phytosulfokine addition. We found that PSK promoted a change in the embryogenic mass of P. massoniana, leading to their development from pro-embryogenic mass (PEM)I to PEMII or PEMIII stages of pro-embryos. In addition, PSK accumulated soluble sugar, protein, and starch, and maintained redox homeostasis during cell line proliferation by reducing H₂O₂ levels. Our findings increase our understanding of how PSK affects somatic embryogensis in P. massoniana, thereby providing a valuable tool for establishing efficient somatic embryogensis systems in conifer species.

The biodiversity of litter can regulate carbon and nutrient cycling during mixed decomposition. It is common knowledge that the decomposition rates of mixed litters frequently deviate from those predicted for these component litter species. However, the direction and magnitude of the nonadditive effects on the degradation of mixed litters remain difficult to predict. Previous studies have reported that the different carbon fractions of leaf litters responded to litter mixture differently, which may help to explain the ambiguous nonadditive effect of diversity on bulk litter decomposition. Therefore, we conducted decomposition experiments on 32 litter mixtures from seven common tree species to test the responses of different carbon fractions to litter diversity in subtropical forests. We found that the overall mass loss of the mixed litter was faster than that estimated from single species. The relative mixing effects (RMEs) of different carbon fractions exhibited different patterns to litter diversity and were driven by different aspects of litter functional dissimilarity. Soluble carbon fractions decomposed more slowly than expected from single species, while lignin fractions decayed more quickly. Moreover, we found that the RMEs of bulk litter decomposition may be determined by the lignin fraction decomposition. Our findings further support that distinguishing the response of different carbon fractions to litter diversity is important for elucidating the nonadditive effects of total litter decomposition.

Pinus massoniana is a critical afforestation and ecological tree species in China. However, the continued existence of this pine is severely threatened by pine wilt disease. Somatic embryogenesis serves as a highly efficient clonal propagation approach. Although significant progress has been made in somatic embryogensis research on P.massoniana, resulting in the successful regeneration of plants, the limited embryogenic potential of improved cell lines and the loss of embryogenic properties resulting from prolonged proliferation have posed obstacles to the industrialization of SE production. Here, we investigated the effect of phytosulfokine on embryogenic development of cell lines from P. massoniana, and then leading to a cascade of physicochemical changes. Eight embryogenic cell lines of P. massoniana were used as research materials to observe phenotype and cytological changes. Physiological factors and the contents of nutrients and endogenous hormones were measured before and after phytosulfokine addition. We found that PSK promoted the embryogenic suspensor mass structure of embryogenic cell lines of P. massoniana. In addition, PSK accumulated soluble sugar, protein, and starch, and maintained redox homeostasis during the cell line proliferation process by reducing H2O2 levels. Further, endogenous hormone indole-3-acetic acid may be the main driver of the embryonic changes of cell lines. Our findings increase our understanding of how PSK affects somatic embryogensis in P. massoniana, thereby providing a valuable tool for establishing efficient somatic embryogensis systems in conifer species.

Slash pine plantations managed jointly for timber and oleoresin require fertilization regimes that support both stem growth and resin production. We conducted a two-year field experiment in a 14-year-old, newly tapped Pinus elliottii plantation in subtropical Jiangxi, China, comprising an unfertilized control (CK) and nine fertilization treatments representing three nitrogen (N) rates, three phosphorus (P) rates, and three compound-fertilizer formulations (three 20 × 20 m plots per treatment). Fertilizers were applied in spring 2022 and 2023. Relative to CK, the two highest P rates increased the 2022–2023 DBH increment by 0.71–0.74 cm (Dunnett’s test, p < 0.05), and DBH and volume increments increased linearly with P rate, although the overall treatment effect on increments was marginal (p = 0.080–0.112). In 2023, resin yield was 20.6%–25.7% higher than in CK under all three N rates, the highest P rate, and the highest compound formulation (p < 0.05), and treatment effects remained significant after adjusting for stem basal area. Growth and total resin yield did not differ significantly between the N-only and P-only series, whereas resin yield per unit basal area was higher under N than under P fertilization (p = 0.022). Soil variables explained 50.6% of the variation in needle traits (adjusted R² = 0.20; p = 0.004). Stem growth was correlated with soil total and available P, soil Cu, and needle P, whereas resin yield was correlated with soil available B and needle N. These associations identify candidate nutrient constraints for dual-purpose slash pine management that should be tested in factorial, multi-site trials.