Negative Effects of Butachlor on the Growth and Physiology of Four Aquatic Plants.

The increasing use of herbicides in intelligent agricultural production is driven by the time-consuming nature of manual weeding, as well as its ephemeral effectiveness. However, herbicides like butachlor degrade slowly and can be washed away by rainwater, ultimately flowing into the farm ponds and posing risks to aquatic plants. To identify and recommend superior restoration strategies that effectively address the challenges posed by butachlor, we investigated the impacts of butachlor on the growth and physiology of four common aquatic plants (i.e., Hydrilla verticillata, Ceratophyllum demersum, Potamogeton maackianus, and Myriophyllum aquaticum) and their potential role in mitigating environmental damage by reducing residual herbicide levels. Our findings indicated that M. aquaticum was tolerant to butachlor, exhibiting higher growth rates than other species when exposed to various butachlor concentrations. However, the concentration of butachlor negatively impacted the growth of H. verticillata, C. demersum, and P. maackianus, with higher concentrations leading to more significant inhibitory effects. After a 15-day experimental period, aquatic plants reduced the butachlor residuals in culture mediums across concentrations of 0.5 mg/L, 1 mg/L, and 2 mg/L compared to non-plant controls. Our findings classified P. maackianus as butachlor-sensitive and M. aquaticum as butachlor-tolerant species. This investigation represents novel research aimed at elucidating the contrasting effects of different concentrations of butachlor on four common aquatic species in the agricultural multi-pond system.

Structural Variability and Functional Prediction in the Epiphytic Bacteria Assemblies of Myriophyllum spicatum.

The underlying principles influencing bacteria community assembly have long been of interest in the field of microbial ecology. Environmental heterogeneity is believed to be important in controlling the uniqueness and variability of communities. However, little is known about the influence of the host macrophytes on epiphytic bacteria assembly. In this study, we used two contrasting artificial water environments (eutrophic and oligotrophic) for reciprocal transplant experiment of Myriophyllum spicatum to examine the colonization of epiphytic bacteria accompanied with plants growth. Comparative analysis addressed a higher species diversity in epiphytic bacteria than in bacterioplankton, and the highest microbiome richness in sediment. Our data revealed that the organization of epiphytic bacterial community was affected by both plant status (i.e. branch number, net photosynthesis rate etc.) and water bodies (i.e. total phosphate, total nitrogen, pH etc.). Moreover, plant status effected the assembly in priority to water. 16S rRNA gene sequencing further indicated that the epiphytic assemblies were motivated by functionalization and interplay with hosts as a whole. The results complemented new evidences for the 'lottery process' in the epiphytic bacteria assembly traits and shed insights into the assembly patterns referring to functional adaptation across epiphytic bacteria and macrophytes.

Responses of propagule germination and sexual reproduction of submerged macrophytes exposed to cadmium.

Submerged macrophytes are considered the main primary producers in shallow lakes. Recently, they have experienced a decline due to increasing environmental impacts, e.g., excessive heavy metal loads. Compared to extensive studies on vegetative growth, reports on effects of heavy metals on propagule germination and reproduction remain scarce. In this study, three experiments were conducted to investigate the effects of cadmium (Cd) on the propagule germination and sexual reproduction of submerged macrophytes. In Experiment I, six Cd concentrations were used (0, 0.05, 0.5, 1, 2.5, and 5 mg L-1), with seed germination found to be marginally affected by Cd treatment. In Experiment II, Cd exposure (5 d) at the six Cd concentrations was performed 15, 30, 60, 90, and 120 d prior to the designated germination date for turions/tubers. The Vallisneria spinulosa tubers did not germinate at ≥ 2.5 mg Cd L-1 when exposed to Cd 90 and 120 d prior to germination, whereas the Potamogeton crispus turions remained viable but with a low germination rate at ≥ 2.5 mg Cd L-1. In Experiment III, with an increase from 0 to 0.5 Cd mg L-1, the fruit weight of Ottelia alismoides and V. spinulosa decreased, whereas the fruit number increased for O. alismoides but not for V. spinulosa. Furthermore, the phenology of sexual reproduction for both species advanced under Cd exposure. In summary, Cd exposure affected the germination of asexual propagules and sexual reproduction of submerged macrophytes, with seeds found to be tolerant of Cd treatment up to 5 mg L-1.

Rh(I)-catalyzed formal [2+2+2] cycloadditions of 1,6-diynes with potassium (Z)-(2-bromovinyl)trifluoroborate: a new strategy and a facile entry to polysubstituented benzene derivatives.

A new strategy for Rh(I)-catalyzed [2+2+2] cycloadditions of 1,6-diynes with potassium (Z)-(2-bromovinyl)trifluoroborate as the third two-atom unit has been realized, which provides a facile entry to polysubstituented benzene derivatives.