Wide applications of glyphosate and 2,4-dichlorophenoxyacetic acid (2,4-D) in rice paddy fields could lead to their residues in environment, posing adverse effects on rice growth and primary producers in the rice ecosystem. This research aims to determine the effects of environmentally relevant concentrations of glyphosate and 2,4-D commercial formulations on Nostoc sp. N1 and rice seedlings. The effects of herbicides on Nostoc sp. N1 were measured from the growth and acute toxicity. The germination and growth were used to determine the effects of herbicides on rice seedlings by measuring their physical and biochemical characteristics. Results showed that while glyphosate had higher toxicity than 2,4-D, both herbicides could stimulate the growth of Nostoc sp. N1 as indicated by their increase in biomass and chlorophyll a content. In Petri dish experiments, Nostoc sp. N1 cells not only promoted the germination of rice seedlings when added alone, but they also alleviated the toxicity of both herbicides to the rice seedlings. In pot experiments, the addition of Nostoc sp. N1 cells combined with herbicides promoted the biochemical characteristics of the rice seedlings by increasing the total chlorophyll, carotenoid and total amino acid content. Our results suggested that environmentally relevant concentrations of glyphosate and 2,4-D formulations should not pose any adverse effects on Nostoc sp. N1. Also, with their toxicity-mitigating and growth-promoting effects on rice seedlings, Nostoc sp. N1 cells could be applied in the alleviation of herbicide residue toxicity in paddy fields.

Chemical fertilizers have been widely used to improve rice production; however, their excessive use can have harmful environmental effects. Therefore, biostimulants are a sustainable option to promote rice yield and improve soil quality. This research focusses on the use of gamma-polyglutamic...

Lychee plantation areas are typically located at varying elevations on mountains to ensure proper drainage. This placement has direct effects on stream and river water flows and consequently influences pesticide residue, water quality and aquatic biodiversity. This research aims to examine the relationships between cypermethrin residue, water quality and phytoplankton diversity in the lychee plantation catchment area in Phayao Province, Thailand, from January to May 2022. The study area was divided into six sampling sites. Water samples were collected for the investigation of cypermethrin residual, physicochemical and biological water quality parameters. The water quality index was used as an overall measurement of water quality. The study also examined the diversity of phytoplankton species and the relationship among cypermethrin residue, water quality and phytoplankton diversity were studied using canonical correspondence analysis. The findings revealed an increasing trend of cypermethrin residue, with the maximum concentration reaching 29.43 mg/L in March. The trend of decreasing water quality scores from Station S1 to Station S5 indicated the influence of land use changes and human activities, especially in the community area (S5), which was characterized by deterioration of water quality. A total of 174 phytoplankton species were categorized into 5 divisions, with Chlorophyta accounting for 61.49% of the total, followed by Bacillariophyta (28.16%) and Cyanophyta (6.32%). The highest Shannon's diversity index and evenness were observed at Stations S3 and S4, respectively. The canonical correspondence analysis revealed an interesting relationship among cypermethrin residue, ammonia nitrogen, chlorophyll a and three algal species: Pediastrum simplex var. echinulatum, Pediastrum duplex var. duplex and Scenedesmus acutus at Station S3. This research implies that pesticide residue and water quality have a direct impact on phytoplankton distribution, illustrating the environmental challenges that occur in various geographical areas. This information can be applied to assist in the development of future sustainable land use management initiatives.

Two new tuberostemonine alkaloids, tuberostemonine L (3) and tuberostemonine M (4) and a new stemofoline alkaloid, (3′S)-hydroxystemofoline (5), along with two known alkaloids, (2′S)-hydroxystemofoline (1) and neotuberostemonine (2) have been isolated from a root extract of an unidentified Stemona species (Stemona sp.). The structure and relative configuration of these new alkaloids has been determined by spectral data interpretation, while the 3′S configuration of 5 was determined from NMR analysis of its (R)- and (S)-Mosher esters.