The lotus (Nelumbo Adans.) is a perennial aquatic plant with important value in horticulture, medicine, food, religion, and culture. It is rich in germplasm and more than 2000 cultivars have been cultivated through hybridization and natural selection. Microsporogenesis and male gametogenesis in the anther are important for hybridization in flowering plants. However, little is known about the cytological events, especially related to the stamen, during the reproduction of the lotus. To better understand the mechanism controlling the male reproductive development of the lotus, we investigated the flower structure of the Asian lotus (N. nucifera). The cytological analysis of anther morphogenesis showed both the common and specialized cytological events as well as the formation of mature pollen grains via meiosis and mitosis during lotus anther development. Intriguingly, an anatomical difference in anther appendage structures was observed between the Asian lotus and the American lotus (N. lutea). To facilitate future study on lotus male reproduction, we categorized pollen development into 11 stages according to the characterized cytological events. This discovery expands our knowledge on the pollen and appendage development of the lotus as well as improving the understanding of the species differentiation of N. nucifera and N. lutea.

Cryptic species are commonly misidentified because of high morphological similarities to other species. One group of plants that may harbor large numbers of cryptic species is the quillworts (Isoëtes spp.), an ancient aquatic plant lineage. Although over 350 species of Isoëtes have been reported globally, only ten species have been recorded in China. The aim of this study is to better understand Isoëtes species diversity in China. For this purpose, we systematically explored the phylogeny and evolution of Isoëtes using complete chloroplast genome (plastome) data, spore morphology, chromosome number, genetic structure, and haplotypes of almost all Chinese Isoëtes populations. We identified three ploidy levels of Isoëtes in China—diploid (2n = 22), tetraploid (2n = 44), and hexaploid (2n = 66). We also found four megaspore and microspore ornamentation types in diploids, six in tetraploids, and three in hexaploids. Phylogenetic analyses confirmed that I. hypsophila as the ancestral group of the genus and revealed that Isoëtes diploids, tetraploids, and hexaploids do not form monophyletic clades. Most individual species possess a single genetic structure; however, several samples have conflicting positions on the phylogenetic tree based on SNPs and the tree based on plastome data. All 36 samples shared 22 haplotypes. Divergence time analysis showed that I. hypsophila diverged in the early Eocene (∼48.05 Ma), and most other Isoëtes species diverged 3–20 Ma. Additionally, different species of Isoëtes were found to inhabit different water systems and environments along the Yangtze River. These findings provide new insights into the relationships among Isoëtes species in China, where highly similar morphologic populations may harbor many cryptic species.

Caragana korshinskii is a deciduous shrub with large eco-economic value and strong tolerance to abiotic stresses. However, the shortage of reliable genetic transformation technology severely hinders its research on stress tolerance mechanisms and stress-resistant gene mining and application. In this study, the embryonic tip of the C. korshinskii seedling was used as the initiating explant to get regenerated plant through the direct organogenesis pathway, which significantly shortened the culture cycle and set the foundation for investigation of Agrobacterium-mediated genetic transformation. Our results suggest that the embryonic tip possesses robust meristem capacity and is an efficient method for transgenic breeding. This research provides a technical basis for asexual reproduction, molecular breeding, and gene function investigation in C. korshinskii by establishing, for the first time, an effective in vitro regeneration system and an Agrobacterium-mediated stable genetic transformation system utilizing the embryonic tip of C. korshinskii as explants.

Background: There is a lack of automatic real-time monitoring of airborne pollens in China and no validation study has been performed. Methods: Two-year continuous automatic real-time pollen monitoring (n = 437) was completed in 2023 (3 April–31 December) and 2024 (1 April–30 November) in Shanghai, China, in parallel with the standard daily pollen sampling(n = 437) using a volumetric Hirst sampler (Hirst-type trap, according to the European standard). Daily ambient particulate matter and meteorological factors were collected simultaneously. Results: Across 2023 and 2024, the daily mean pollen concentration was 7 ± 9 (mean ± standard deviation (SD)) grains/m³ by automatic monitoring and 8 ± 10 grains/m³ by the standard Hirst-type method, respectively. The spring season had higher daily pollen levels by both methods (11 ± 14 grains/m³ and 12 ± 15 grains/m³) and the daily maximum reached 106 grains/m³ and 100 grains/m³, respectively. A strong correlation was observed between the two methods by either Pearson (coefficient 0.87, p < 0.001) or Spearman’s rank correlation (coefficient 0.70, p < 0.001). Compared to the standard method, both simple (R² = 0.76) and multiple linear regression models (R₂ = 0.76) showed a relatively high goodness of fit, which remained robust using a 5-fold cross-validation approach. The multiple regression mode adjusted for five additional covariates: daily mean temperature, relative humidity, wind speed, precipitation, and PM₁₀. In the subset of samples with daily pollen concentration ≥ 10 grains/m³ (n = 98) and in the spring season (n = 145), the simple linear models remained robust and performed even better (R² = 0.71 and 0.83). Conclusions: This is the first validation study on automatic real-time pollen monitoring by volumetric concentrations in China against the international standard manual method. A reliable and feasible simple linear regression model was determined to be adequate, and days with higher pollen levels (≥10 grains/m³) and in the spring season showed better fitness. More validation studies are needed in places with different ecological and climate characteristics to promote the volumetric real-time monitoring of pollens in China.