Graphene oxide improves the tolerance of Tartary buckwheat to continuous cropping by coordinating the antioxidant defense system and endogenous hormone levels

• Graphene oxide increased the antioxidant capacity and osmotic adjustment substance content. • Graphene oxide coordinated the dynamic balance of endogenous IAA and ABA contents. • Graphene oxide had concentration dependence in improving tolerance to continuous cropping. Continuous cropping obstacles seriously restrict the yield of Tartary buckwheat. Graphene oxide (GO) is shown to play an important role in defense mechanism to plant abiotic stress. However, the relationship between GO and improving continuous cropping tolerance is unclear. The main objective of this study was to analyze the physiological mechanism of GO in alleviating continuous cropping injury. A 2-year field experiment was conducted on Tartary buckwheat (Jinqiao 2) to investigate the characteristics with five GO treatments, namely, 0 (control), 25 (G 1 ), 50 (G 2 ), 100 (G 3 ), and 200 mg L –1 (G 4 ). With increasing the GO application concentration, the rhizosphere soil nutrient content, root morphology and activity, photosynthetic characteristics and chlorophyll content, antioxidant enzyme activities, osmotica and auxin (IAA) content, agronomic traits, and yield initially increased and then decreased. The contents of malonaldehyde, superoxide anion free radical, and abscisic acid (ABA) initially decreased and then increased. Compared with CK, the yields subjected to continuous cropping and treated with G 1 , G 2 , G 3 , and G 4 were 1.28, 1.58, 1.43, and 1.16 times, respectively. GO treatment, especially G 2 treatment, can improve the tolerance and increase the yield of Tartary buckwheat to continuous cropping, and it is suitable for widespread use by farmers in Tartary buckwheat production.