Liquid-liquid extraction and solid phase extraction followed by high-performance liquid chromatography (HPLC) connected with ultraviolet (UV) detection were used for the determination of phytohormones. The parameters influencing the performance of the HPLC-UV method, including composition of the mobile phase for gradient elution, column temperature, flow rate, and detection wavelength, were optimized. This method can simultaneously determine 11 phytohormones, including nine cytokinins, indole-3-acetic acid, and abscisic acid. The limit of detection of this method is 0.22 to 1.1 µg L⁻¹, and the coefficient factors of linear regression are >0.998. The recoveries of the target phytohormones ranged between 62.1~109.4%, and the relative standard deviations were <10%. This method is suitable for determining phytohormones, especially cytokinins, in young panicles, roots, and xylem sap of rice plants.

Diacylglycerol kinase (DGK) is a lipid kinase that phosphorylates diacylglycerol (DAG) to generate phosphatidic acid (PA). Based on converting one important signaling molecule (DAG) to another (PA), DGK plays an important role in plant responses to abiotic stress, including waterlogging stress. However, no studies have been reported on the characterization of the DGK gene family in the waterlogging-tolerant kiwifruit germplasm Actinidia valvata Dunn. In this study, we identified 18 AvDGK genes in the A. valvata genome. The phylogenetic analysis showed that AvDGKs can be classified into three clusters, and members within the same cluster have similar domain distributions, exon-intron structures, and conserved motif compositions. The chromosome localization analysis revealed that all AvDGK genes are located across 18 different chromosomes. There were 29 duplicated gene pairs in A. valvata and all had undergone purifying selection during evolution. The promoter cis-element analysis revealed that the cis-elements within AvDGK genes are associated with multiple functions, including phytohormone signal transduction, stress responses, and plant growth and development. The expression pattern analyses indicated that AvDGKs play important roles in fruit development and plant responses to waterlogging stress. The AvDGK gene family in the tetraploid A. valvata genome might promote PA synthesis and subsequent signal transduction both under short- and long-term waterlogging stresses. These results provide information regarding the structural characteristics and potential function of AvDGK genes within A. valvata and lay a fundamental basis for further research into breeding to enhance the kiwifruit’s tolerance to waterlogging stress.

The genus Stephania, which is rich in alkaloids, has been used as a traditional medicine or folklore herb against numerous ailments in China. However, the understanding of the variation within the genus Stephania is obscure, which limits the optimal utilization of the genus. An evaluation of the variation within the genus Stephania would help screen the ideal Stephania genotypes for drug utilization. In the present study, alkaloids in the tubers of four commonly cultivated Stephania species in China, i.e., the genotype Stephania kwangsiensis Lo. (SK-guangxi) from Guangxi Province and three Stephania yunnanensis H.S. Lo. genotypes (SY-xueteng, SY-hongteng, and SY-lvteng) sourced from Yunnan Province, were investigated, and the genus variations were compared. The results revealed significant variations in the abundance of alkaloids in tubers within the genus Stephania. The Stephania genotypes SY-xueteng and SY-hongteng showed a relatively high abundance of total alkaloids compared with the Stephania genotypes SK-guangxi and SY-lvteng. Specifically, the Stephania genotype SY-xueteng had a relatively high abundance of palmatine in tubers, and the Stephania genotype SY-hongteng exhibited a high abundance of stephanine in tubers. Our study provides foundations for further utilization of ideal Stephania genotypes by clarifying the variations in the alkaloid contents within the genus in China.

The genetic diversity of 52 kiwifruit wild germplasms, which were collected by the kiwifruit germplasm nursery of the Guangxi Institute of Botany, was studied using start-codon-targeted (SCoT) molecular markers. The objective was to understand the genetic relationships of the 52 kiwifruit wild germplasms. The results showed that a total of 113 bands were amplified from 52 wild kiwifruit germplasms using 10 primers (9–17 bands per primer, 11.3 on average), of which 103 (91.15%) were polymorphic bands (10.3 bands per primer). The genetic identity of the 52 wild kiwifruit germplasms was in the range of 0.405–1.000, with an average of 0.709. The genetic distance was 0.000–0.904, with an average of 0.355. At the threshold of 0.650, the germplasms were clustered into three clusters. The genetic distances between Guilin and Fushekuoye and between Jinhua and Liangye were both the smallest (0.000), meaning they had a similarity of 100%, as indicated by the SCoT molecular markers. In conclusion, the genetic relationships at the molecular level (genetic distance) were clustered preferentially according to the place of origin instead of by morphological classification, geographical distribution, or ploidy. The genetic relationships between wild kiwifruit germplasms were partially verified through disease resistance analysis.

Illicium difengpi K.I.B. et K.I.M. is a member of the Illiciaceae family with a yet not fully explored utilization value. To provide references for the systematic understanding of I. difengpi (Illiciaceae), the morphological and structural characteristics, wild resource distribution, chemical compounds, pharmacological effects, utilization, and protective measures of this species are reviewed. We conclude that (i) I. difengpi (Illiciaceae) is an endemic and indigenous medicinal species that has been used to treat rheumatoid arthritis and traumatic injury in China; (ii) I. difengpi (Illiciaceae) can endure various abiotic stresses, especially extreme drought, and thus has scientific value for exploring adaptive mechanisms of tolerance to extreme drought and in the ecological restoration of karst rocky desertification areas; and (iii) the beautiful tree shapes of I. difengpi (Illiciaceae) give it potential ornamental value. However, the wild resources of I. difengpi (Illiciaceae) have rapidly decreased, and there is an urgent need to protect this endangered species to maintain its diversity. Protection measures include the protection of wild germplasm resources, the establishment of an I. difengpi (Illiciaceae) germplasm resource bank, and the development of large-scale ecological planting techniques. In further research, the medicinal and scientific value of I. difengpi (Illiciaceae) should be systematically explored to clarify the plant’s effective pharmaceutical value, clinical applications, mechanisms of drought adaptation, and genetic diversity.

Heat stress during the flowering stage induces a remarkable decrease in rice spikelet fertility, mainly due to poor pollination manifesting as insufficient pollen deposited on the stigma. It is hypothesized that stigma exsertion, which confers a pollination advantage, may enhance pollen reception and improve female reproductive success under heat stress. The present study aimed to investigate the role of stigma exsertion in spikelet fertility under nocturnal heat. Four rice cultivars exhibiting distinct heat tolerance and twenty rice cultivars with varying degrees of stigma exsertion were grown and subjected to high nighttime temperature treatment at anthesis, in 2023 and 2019, respectively. Heat-tolerant rice cultivars had a relatively low percentage of spikelets with exserted stigmas, and vice versa. Under nocturnal heat stress, rice cultivars exhibiting higher stigma exsertion showed significantly greater reductions in spikelet fertility compared to lower stigma exsertion cultivars. The spikelet fertility of rice cultivars with a higher degree of stigma exsertion was reduced more seriously than that of cultivars with a lower degree of stigma exsertion. Rice spikelet fertility positively correlated with the percentage of hidden stigmas, and exogenous substance-induced increased stigma exsertion led to reduced spikelet fertility under nocturnal heat. These results indicate that a hidden stigma contributes to higher spikelet fertility, while increased stigma exsertion aggravates spikelet sterility in rice cultivars under nocturnal heat conditions. It is proposed that hidden stigmas could serve as a novel breeding trait for sustaining rice spikelet fertility against nocturnal heat stress.