Adventitious roots play a crucial role in the nourishment and propagation of arboreal vegetation. In order to shed light on the physiological and biochemical characteristics of the challenging-to-propagate mulberry tree species, an investigation was conducted. This study aimed to compare the responses of various root morphological indicators, endogenous hormones, and oxidase activities in the “Yueshenda 10” fruit mulberry, at different stages of treatment. The ultimate objective was to identify the factors influencing the process of root development. The findings revealed a distinct ”/\“ pattern in the levels of IAA and JA within the cuttings. Conversely, the changes in ABA, ZR, and GA₃ exhibited a ”/\/“ pattern. The fluctuation of the IAA/ABA values followed a ”\/\“ mode, whereas the IAA/ZR values initially increased, followed by a subsequent decrease. The correlation between the initial concentrations of these five endogenous hormones and the rooting rate displayed variations. Notably, IAA demonstrated the strongest association with the rooting rate, exhibiting a positive correlation with both IAA and ZR. Regarding the activity of three antioxidant enzymes (IAAO, POD, and PPO), a ”/\“ trend was observed, wherein the enzyme activity increased under ABT1 treatment. However, the peak activity levels of the enzymes appeared during different periods: callus generation, rooting induction, and adventitious root expression, respectively. Overall, the most effective treatment for promoting root development and significantly enhancing the root growth parameters of mulberry was found to be 800 mg/L ABT1. Exogenous hormone treatment expedited the synthesis of antioxidant enzymes, thereby shortening the rooting time and facilitating root formation.

Adventitious roots play a crucial role inr the nourishment and propagation of arboreal vegetation. In order to shed light on the physiological and biochemical characteristics of the challenging-to-propagate mulberry tree species, an investigation was conducted. This study aimed to compare the responses of various root morphological indicators, endogenous hormones, and oxidase activities in the "Yueshenda 10" fruit mulberry, at different stages of treatment. The ultimate objective was to identify the factors influencing the process of root development. The findings revealed a distinct '/\' pattern in the levels of IAA and JA within the cuttings. Conversely, the changes in ABA, ZR and GA3 exhibited a '/\/' pattern. The fluctuation of IAA/ABA values followed a '\/\' mode, whereas the IAA / ZR values initially increased, followed by a subsequent decrease. The correlation between the initial concentrations of these five endogenous hormones and the rooting rate displayed variations. Notably, IAA demonstrated the strongest association with the rooting rate, exhibiting a positive correlation with both IAA and ZR. Regarding the activity of three antioxidant enzymes (IAAO, POD and PPO), a '/\' trend was observed, wherein the enzyme activity increased under ABT1 treatment. However, the peak activity levels of the enzymes appeared during different periods: germination, induction, and expression, respectively. Overall, the most effective treatment for promoting root development and significantly enhancing the root growth parameters of mulberry was found to be 800mg/L ABT1. Exogenous hormone treatment expedited the synthesis of antioxidant enzymes, thereby shortening the rooting time and facilitating root formation.

Mulberry trees are not only economically significant forest trees with substantial added value but also serve as exceptional candidates for environmental management and ecological enhancement. However, in the widely applied cutting propagation of mulberry, the intensity of adventitious root formation in cuttings has long remained a key challenge in the cutting process. Our research group previously found that 800 mg/L Rooting Powder No. 1 (ABT1) has an obvious promoting effect on the development of adventitious roots in mulberry cuttings, but its molecular mechanism has not yet been studied. In this research, transcriptome sequencing (RNA-seq) technology was employed to sequence the ‘Yueshenda 10’ mulberry during four distinct cutting stages. Through Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analysis, shifts in gene expression and metabolic pathways were scrutinized, pinpointing the pivotal role of plant hormones in this context. Furthermore, using Weighted Gene Co-Expression Network Analysis (WGCNA), the study analyzed gene expression across all samples, identifying two modules, “black” and “blue”. These modules were predominantly expressed in the treatment group during the rooting phase and minimally expressed in the control group. Critical genes such as gene21267 and gene16291 from the black module, alongside gene18291 and gene20028 from the blue module, were identified as key to the rooting success of the ‘Yueshenda 10’ cuttings. This investigation not only supports the nutrient propagation and effective use of mulberry trees but also clarifies the molecular basis of adventitious root formation in these plants, extending the research to other related species. This work fosters the diversification and enhancement of the mulberry industry chain.

Reproductive barriers severely limit interspecific hybridization success among Hydrangea macrophylla, H. paniculata, and H. arborescens, thereby restricting the combination of ornamental traits and cold hardiness. We evaluated cross-compatibility, pollen tube growth, and embryo development in both direct and reciprocal crosses involving H. macrophylla with H. paniculata and H. arborescens. Both species pairs exhibited pronounced unilateral incompatibilities. When H. macrophylla served as the maternal parent, the percentages of seedling emergence were higher, whereas reciprocal crosses produced >84% ovary swelling but resulted in almost no seedlings. Fluorescence microscopy revealed mild prezygotic barriers in direct crosses but strong inhibition of pollen germination and pollen tube growth in reciprocal crosses. Paraffin section observations showed that postzygotic barriers were the primary cause of hybrid failure, with endosperm-type abortion predominating in direct crosses and embryo-type or complete abortion in reciprocal crosses. Consistent with these abortion patterns, direct crosses maintained higher proportions of normal embryos, whereas reciprocal crosses dropped below 10% at the globular stage and approached 0% at later stages. These findings support the use of timely embryo rescue for direct crosses and targeted mitigation of prezygotic barriers in reciprocal crosses to improve Hydrangea interspecific hybridization efficiency.