Plants

Silicon deposition in grasses produces silica bodies with characteristic morphologies and distributions, but our understanding of their organ-specific diversity and developmental silicification remains limited beyond extensively studied crop species. Here, we investigated silica body formation in Zingeria biebersteiniana, a diploid grass with 2n = 4 chromosomes, by combining organ-level morphological characterization with a post-transplant developmental analysis. Dry-ash preparations were examined by fluorescence microscopy and quantified using digital image analysis. Mature soil-grown plants exhibited organ-associated silica body morphotypes in leaf blades, leaf sheaths, stems, glumes, lemmas, and paleae, with marked differences in morphology, distribution, and epidermal coverage. Plants maintained in vitro on Murashige and Skoog (MS) medium without intentionally added Si showed little to no detectable leaf silicification. Following transfer to soil, silica bodies were readily detectable by Day 7 in both Leaf 3, which was fully expanded at transplantation, and the younger, developing Leaf 2. Descriptive analysis showed broad silica-body area distributions that shifted during the post-transplant period. Spatial imaging further revealed interplant heterogeneity: three plants showed more distal and marginal silicification, whereas nine showed relatively uniform blade-wide patterns. These results provide an anatomical and developmental framework for investigating silicon biology in Z. biebersteiniana and demonstrate the utility and limitations of fluorescence-based dry-ash imaging for descriptive analysis of silicification in grasses.

Pharmaceutical and Personal Care Products (PPCPs) are emerging aquatic contaminants. Existing studies investigating the uptake of PPCPs by aquatic plants under hydroponic conditions have mostly been performed in non-competitive systems. Few reports are available regarding plant uptake and translocation of PPCPs under multi-species coexistence and interspecific competition. In this study, competitive hydroponic experiments were conducted in a greenhouse using ¹⁴C-triclosan to explore the uptake and distribution of triclosan in six hydrophytes: water spinach, purple perilla, cress, penny grass, cane shoot, and rice. The results showed that the triclosan uptake capacity of aquatic plants in the competitive hydroponic system followed the order: cress > water spinach > cane shoot > rice > penny grass > purple perilla. The root ¹⁴C-triclosan concentrations in water spinach (222.15–564.54 μg g⁻¹) and cress (198.66–569.25 μg g⁻¹) were significantly higher than those of the other species. Triclosan mainly accumulated in roots (90.36–99.04% of total plant uptake), with shoot levels 2–3 orders of magnitude below roots. Compared with non-competitive hydroponic conditions, interspecific competition exerted no significant effects on the uptake, distribution and translocation of triclosan in plants. This work advances the understanding of triclosan accumulation-translocation in hydrophytes under competitive conditions and supports risk assessment for triclosan.

Winter turnip rape (Brassica rapa L.) is an important winter oilseed crop in the arid and cold regions of northern China due to its strong cold tolerance and wide adaptability. However, its prevalent self-incompatibility readily causes inbreeding depression, leading to declines in yield and quality and creating difficulties for cultivar breeding and pure-line propagation. To clarify how self-compatibility affects growth, yield, quality, and physiological traits, highly self-compatible (HSC), self-compatible (SC), and self-incompatible (SI) lines were compared under self-pollination and open pollination, and leaf antioxidant enzyme activities and endogenous hormone contents were measured. The results showed that the effects of selfing on seedling vegetative growth, agronomic traits, quality, and biomass were far smaller in HSC and SC lines than in SI lines, with inbreeding depression markedly alleviated. The mean inbreeding depression rates (IDRs) of major traits in HSC, SC, and SI lines were 4.32%, 8.14%, and 20.05%, respectively, the IDRs of effective silique number per plant were 3.03%, 5.22%, and 20.53%, and those of seed yield were 4.69%, 9.39%, and 27.90%. Line-level ANOVA and Tukey tests (three lines per group) confirmed that the IDRs of SI lines were significantly higher than those of HSC lines for all six core traits, with SC lines intermediate. Physiological and biochemical analyses indicated that HSC lines maintained higher SOD activity, and the contents of growth-promoting hormones, such as gibberellin (GA), cytokinin (CTK), and auxin (IAA), were generally higher than in SI lines, whereas CAT activity did not show a consistent advantage: in HSC lines CAT did not differ significantly between SP and OP (the two shared a significance group), and under open pollination SI-OP was grouped with HSC-OP and SC-OP. In contrast, after selfing, SI lines accumulated more abscisic acid (ABA), whereas the ethylene (ETH) differences were not consistently significant and the coordination of their antioxidant enzymes was altered rather than disrupted. Correlation analysis showed that the contents of growth-promoting hormones (GA, CTK, IAA, and BR) were significantly or highly significantly positively correlated with yield traits, such as seed yield per plant, effective silique number per plant, and thousand-seed weight, whereas ABA and ETH contents were highly significantly negatively correlated. A structural equation model, based on composite scores of hormones, enzymes, growth, and yield and quality, indicated that the hormone composite was strongly associated with the growth composite (standardized path coefficients of hormone → growth and growth → yield and quality were 0.816 and 0.535, respectively), whereas the enzyme composite was directly associated with yield and quality (0.291). These paths reflect statistical associations among the composite scores rather than confirming the specific underlying mechanisms, and vegetative growth was the main mediator linking the hormone composite to yield and quality. To our knowledge, self-compatibility in winter turnip rape can maintain relatively stable plant growth and development as well as yield and quality by alleviating inbreeding depression and maintaining physiological metabolism and hormone homeostasis. This study provides a theoretical basis for the screening and utilization of self-compatible germplasm and for high-yield breeding of winter turnip rape; because stress tolerance was not directly measured, any extrapolation to stress-resistant breeding requires dedicated stress-tolerance experiments in future work.