Acta Agriculturae Boreali-Sinica ›› 2026, Vol. 41 ›› Issue (1): 86-96. doi: 10.7668/hbnxb.20195886

Special Issue: Hot Article Cultivation & Physiology

• Tillage & Cultivation·Physiology & Biochemistry • Previous Articles     Next Articles

Impact of Acid Stress on Physiological Metabolism and Antioxidant Regulatory Gene Expression in Hainan Green Sweet Orange

ZHAO Ya, FAN Hongyan, LI Shaoka, YAN Caibin, BAI Li, HUANG Haijie, XIAO Min   

  1. Institute of Tropical Fruit Trees,Hainan Academy of Agricultural Sciences,Hainan Field Scientific Observation and Research Station for Tropical Fruit Trees,Ministry of Agriculture and Rural Affairs,Haikou Tropical Fruit Tree Scientific Observation and Experimental Station,Key Laboratory of Tropical Fruit Tree Biology of Hainan Province, Key Laboratory of Genetic Resources Evaluation and Utilization of Tropical Fruits and Vegetables (Co-construction by Ministry and Province),Ministry of Agriculture and Rural Affairs,Haikou 571100,China
  • Received:2025-03-03 Published:2026-02-28

Abstract:

This study aimed to investigate the effects of acidic soil on the growth metabolism and photosynthesis of Hainan green sweet orange (Citrus sinensis L.)and to elucidate its antioxidant regulatory mechanisms under acid stress.A pot experiment was conducted to analyze the physiological metabolic changes,antioxidant responses,and expression patterns of key antioxidant enzyme regulatory genes in green sweet orange under acid stress.The results showed that the plant height growth,leaf area and fresh weight of green sweet orange plants decreased significantly under a strongly acidic soil environment,with the most serious effect of pH 3.5 treatment;the weakly acidic(pH 6.5)soil could promote the growth of plants,which manifested as positive growth in the amount of each growth index.Strong acid treatment significantly impaired photosynthesis and normal growth metabolism of green sweet orange leaves,manifested as negative growth in transpiration rate(Tr)and stomatal conductance(Gs)were significantly reduced.Superoxide dismutase(SOD)and phenylalanine ammonia-lyase(PAL)activities increased by 6.60-fold and 5.90-fold at 24 h post-treatment under pH 3.5.The malondialdehyde(MDA)content in leaves treated with pH 3.5 increased by 6.47-fold compared to the initial time point(0 h),significantly higher than that under pH 6.5.Principal component analysis(PCA)and redundancy analysis(RDA)revealed a significant negative correlation between enzyme activity and physiological-biochemical indices(R2=0.82).Gene expression analysis demonstrated that CsSOD and CsPAL reached peak levels at 24,48 h post-stress respectively and remained upregulated within 72 h,showing 2.33-fold and 2.64-fold increases compared to 0 h,respectively.In summary,strongly acidic soil inhibits the growth and development of green sweet orange by reducing photosynthetic pigment content and metabolic efficiency.SOD and PAL serve as key antioxidant enzymes in response to acid stress,with CsSOD and CsPAL genes dynamically regulating enzymatic activity to mitigate stress.

Key words: Green sweet orange, Acid stress, Physiological metabolism, Photosynthetic metabolism, Antioxidant enzyme, Regulatory gene

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Cite this article

ZHAO Ya, FAN Hongyan, LI Shaoka, YAN Caibin, BAI Li, HUANG Haijie, XIAO Min. Impact of Acid Stress on Physiological Metabolism and Antioxidant Regulatory Gene Expression in Hainan Green Sweet Orange[J]. Acta Agriculturae Boreali-Sinica, 2026, 41(1): 86-96. doi: 10.7668/hbnxb.20195886.

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