文献类型：期刊文献

英文题名：Effects and mechanisms of phytohormones in enhancing the resistance of Oocystis borgei to high ammonium nitrogen stress

作者：Song, Xinyue[1];Liu, Yang[2];Deng, Chengcheng[1];Dong, Zhongdian[3];Hu, Zhangxi[1];Huang, Xianghu[1];Li, Changling[1];Zhang, Ning[1,3]

机构：[1]Guangdong Ocean Univ, Fisheries Coll, Lab Algae Resource Dev & Aquaculture Environ Ecol, Zhanjiang 524088, Peoples R China;[2]Sichuan Acad Agr Sci, Fisheries Res Inst, Chengdu 611731, Sichuan, Peoples R China;[3]Guangdong Ocean Univ, Key Lab Aquaculture South China Sea Aquat Econ Ani, Fisheries Coll, Guangdong Higher Educ Inst, Zhanjiang 524088, Peoples R China

年份：2025

卷号：15

期号：1

外文期刊名：SCIENTIFIC REPORTS

收录：SCI-EXPANDED(收录号：WOS:001526484100010)、、Scopus(收录号：2-s2.0-105010537315)、WOS

基金：This research was financially supported by the National Natural Science Foundation of China (32102796).

语种：英文

外文关键词：High ammonium nitrogen stress (HANS); Phytohormones; Oocystis borgei; Photosynthetic efficiency; Antioxidant capacity; Nitrogen metabolism

外文摘要：Excessive ammonium nitrogen (NH4+-N) in aquatic environments poses significant challenges for wastewater treatment and microalgae-based bioremediation. This study investigated the effects of phytohormones on enhancing the tolerance of Oocystis borgei to high NH4+-N stress and explored the underlying mechanisms. Growth of O. borgei was significantly inhibited by NH4+-N in a dose-dependent manner, with 500 mgL-1 NH4+-N selected as the stress concentration. Supplementation with 10-6 M indole-3-acetic acid (IAA), gibberellic acid (GA3), or zeatin (ZT) significantly alleviated growth inhibition under high NH4+-N stress, increasing cell density by 22-26% and specific growth rate by 217-282% compared to the HAN group. No significant differences were observed among the tested phytohormones. Phytohormone treatments mitigated photosynthetic inhibition by enhancing chlorophyll a (Chla) and carotenoid (Car) contents, as well as Fv/Fm and phi PSII values. While rbcL gene expression remained suppressed, phytohormones reduced oxidative stress by decreasing malondialdehyde (MDA) content and modulating superoxide dismutase (SOD) and catalase (CAT) activities. Additionally, phytohormones promoted nitrogen metabolism by significantly increasing glutamine synthetase (GS) activity and gene expression. This study provides insights into the protective mechanisms of phytohormones against high NH4+-N stress in O. borgei, offering potential strategies for enhancing algal-based treatment of high-ammonium wastewater.