Photosynthetic index and nitrogen assimilation in rapeseed seedlings transplanted in soil with ammonium glufosinate / Índice fotossintético e assimilação de nitrogênio em plântulas de colza transplantadas em resposta a resíduos de glufosinato presentes no solo

ABSTRACT: Herbicide application is an effective weed control method for mitigating crop yield loss; however, herbicide overuse can cause toxicity in non-target plants. The present study evaluated the effects of glufosinate at recommended dose for agricultural application (0.45 kg ha-1) and at overuse dose (0.90 kg ha-1) glufosinate application on photosynthetic performance and nitrogen assimilation of the rapeseed varieties D148 and Zhongshuang 11 (ZS11). Both glufosinate concentrations significantly decreased the content of chlorophyll and nitrogenous compounds, except free proline, and the activity of glutamine synthetase and glutamate synthase, and increased the activity of glutamic acid dehydrogenase in both varieties. When the concentration of glyphosate was 0.45kg ha-1, the nitrogen assimilation of the two varieties decreased, which indicated that the recommended dosage inhibited the nitrogen assimilation of the two varieties; however, the increase of net photosynthetic rate of D148 and the decrease of that of ZS11 mean that D148 is more tolerant to the recommended dose of glyphosate than ZS11. The 0.90 kg ha-1 dosage was toxic to both rapeseed varieties. Overall, our results indicated that herbicide overuse inhibited the photosynthetic rate and nitrogen assimilation in rapeseed seedlings, and it is essential to apply a suitable glufosinate dose based on the variety grown to minimize adverse effects on crops and environment.

RESUMO: A aplicação de herbicidas é um método eficaz de controle de ervas daninhas para mitigar a perda de produtividade das culturas. No entanto, o uso excessivo de herbicidas pode causar toxicidade em plantas não alvo. O presente estudo avaliou os efeitos da dose recomendada para aplicação agrícola (0.45 kg ha-1) e dose excessiva (0.90 kg ha-1) de glufosinato no desempenho fotossintético e assimilação de nitrogênio das variedades de colza D148 e Zhongshuang 11 (ZS11). Ambas as concentrações de glutamato diminuíram significativamente o teor de clorofila e compostos azotados, exceto a prolina livre, e a atividade de síntese da glutamina e de síntese de glutamato, e aumentaram a atividade de desidrogenase do ácido glutâmico em ambas as variedades. Quando a concentração de glifosato foi 0.45 kg ha-1, a assimilação de azoto das duas variedades diminuiu, o que indicou que a dosagem recomendada de glifosato inibiu a assimilação de azoto das duas variedades de colza. Entretanto, a taxa fotosintética líquida do D148 aumentou enquanto o do ZS11 diminuiu, o que significa que o D148 é mais tolerante a dose recomendada de glifosato do que o ZS11. A dose de 0.90 kg ha-1 de glifosato foi prejudicial para as mudas de duas variedades de colza. Em geral, os nossos resultados indicam que o uso excessivo de glufosinato inibe a taxa fotossintética e a assimilação de nitrogênio em mudas de colza, sendo essencial aplicar uma dose adequada deste herbicida com base na variedade cultivada para minimizar os efeitos adversos nas culturas e no meio ambiente.

Metabolomics investigation of cutaneous T cell lymphoma based on UHPLC-QTOF/MS.

OBJECTIVES: The identification of cutaneous T cell lymphoma (CTCL) biomarkers may serve as a predictor of disease progression and treatment response. The aim of this study was to map potential biomarkers in CTCL plasma. DESIGN AND METHODS: Plasma metabolic perturbations between CTCL cases and healthy individuals were investigated using metabolomics and ultrahigh performance liquid chromatography­quadrupole time-of-flight mass spectrometry (UHPLC-QTOF/MS). RESULTS: Principal component analysis (PCA) of the spectra showed clear metabolic changes between the two groups. Thirty six potential biomarkers associated with CTCL were found. CONCLUSIONS: Based on PCA, several biomarkers were determined and further identified by LC/MS/MS analysis. All of these could be potential early markers of CTCL. In addition, we established that heparin as anticoagulant has better pre-treatment results than EDTA with the UHPLC-QTOF/MS approach.

[Development characteristics of aquatic plants in a constructed wetland for treating urban drinking water source at its initial operation stage].

The development characteristics and improvement measures of aquatic plants were studied in Shijiuyang Constructed Wetland (SCW) at its initial operation stage. SCW was a large-scale wetland aiming to help relieve the source water pollution in Jiaxing City. A checklist of vascular plants in SCW was built, and species composition, life forms, biomass and association distributions were examined. Our objectives were to examine the diversity and community structure of aquatic plants in SCW at its initial operation stage, and to find out the possible hydrophyte improvement measures. The survey results showed that there were 49 vascular plant species belonging to 41 genera, 25 families in SCW, which greatly exceeded the artificially transplanted 13 species. The life forms of present aquatic plants in SCW were dominated by hygrophilous plants (20 species) and emerged plants (17 species), which accounted for 75.5% of the total number of aquatic plants. The aquatic plants transplanted artificially were dominated by emerged plants (accounted for 69.2%), while those naturally developed were predominated by hygrophilous plants (accounted for 47.2%). The horizontal distribution of aquatic plant community in SCW was mixed in the form of mosaics, which made up typical association complex. Except association Aeschynomene indica L., the dominant species of other associations were all those transplanted artificially. The naturally grown species scattered throughout the SCW and only occupied a small percentage. A marked difference was detected on the species and species richness of aquatic plants in different regions of SCW. Biomass of aquatic plant associations in SCW was 167.7 t. SCW has shown a trend of succession heading for quick increase of plant diversity at the primary operation stage. This trend provides a good material base for the future stable community of aquatic plants in SCW. According to the current status of aquatic plants, some suggestions were put forward on the further optimization and utilization of aquatic plant systems in SCW.