Cyanobacterial bloom affects structural and functional succession of microbial communities in urban wetland sediments in the Qinghai Plateau

Algal blooms significantly affect microbial communities in wetland ecosystems.However,little is known about the succession of sediment microbial communities during algal blooms.This study aimed to investigate the temporal patterns of sediment bacterial community structure and function succession during algal blooms(March to May 2022)with high-throughput sequencing technology.To this end,algal blooms were divided into the bloom stage(BS),decomposition stage(DS)and end stage(ES).The results showed that:(i)The algal blooms were dominated by Microcystis species within Cyanobacteria.Both phytoplankton abundance and biomass reached the peak in the BS,with 45.78×105 cells/L and 5.97 mg/L,respectively.(ii)The alpha diversity indices of the sediment bacterial community showed a monotonically increasing trend,with the lowest value in the BS.Cyanobacterial blooms reduced the relative abundance of Actinobacteria and Chloroflexi,and raised that of Firmicutes,Proteobacteria and Bacteroidetes.(iii)Cyanobacterial blooms remarkably decreased the complexity of the co-occurrence network of the sediment bacterial community,which resisted extreme environmental conditions in the BS and DS by increasing positive relationships.(iv)Mantel test showed that phytoplankton biomass,T,dissolved oxygen and organic carbon had significant effects on the sediment bacterial community.The results of this study are important for the ecological management of algal blooms through microorganisms.

Evaluation on the fresh eating quality of tree peony flowers

Tree peony(Paeonia suffruticosa)is an ornamental and medicinal plant in China.The fresh eating of flower petals has gradually become a new idea for further development.This study analyzed the sensory indexes,nutritional indexes and antioxidant indexes of fresh flowers of five cultivars,namely,‘Fengdan’(P.ostia‘Fengdan’),‘Xiangyu’(P.suffruticosa‘Xiangyu’),‘Zhaofen’(P.suffruticosa‘Zhanfen’),‘Luoyanghong’(P.suffruticosa‘Luoyanghong’)and‘High Noon’(P.‘High Noon’),to provide a theoretical basis for eating fresh tree peony flowers.The aroma volatiles of petals mainly comprised terpenes,alcohols and alkanes.‘Luoyanghong’and‘High Noon’have brighter colors.The taste test showed that‘Luoyanghong’,‘High Noon’and‘Xiangyu’were the most palatable.‘High Noon’contained the highest soluble sugar content,‘Luoyanghong’contained the highest starch and vitamin C(VC)levels,and‘Zhaofen’contained the highest soluble protein content.The contents of bioactive compounds were the highest in‘Luoyanghong’,and superoxide dismutase(SOD)activity was the highest in‘Xiangyu’.The petals were rich in essential amino acids,with the highest amount in‘Xiangyu’.‘Luoyanghong’and‘High Noon’showed strong antioxidant capacity.Therefore,tree peony flowers have excellent sensory qualities,abundant nutrients and strong antioxidant activity and could be further developed as a food to be eaten fresh.The results showed that tree peony flowers had great edible potential.Flowers of red and yellow cultivars can be considered for fresh eating on the basis of the traditional consumption of white and pink tree peony flowers.