Effect of continuous grafting on growth and cadmium content of tomato cuttings and seedlings

This pot experiment elucidated the dynamic effects of continuous grafting on cadmium (Cd) accumulation in tomato plants, investigating its impact on Cd distribution, accumulation characteristics, and generational responses. The results demonstrated that continuous grafting significantly reduced both biomass and antioxidant enzyme activities in tomato scions. Specifically, compared to non-grafted controls, the root biomass of secondary and tertiary grafted plants decreased by 40.21% and 40.38%, respectively. Concurrently, a reduction in DNA methylation levels was observed across cuttings and grafted generations. Demethylation emerged as the predominant pattern in seedlings, while hypermethylation was notably present in the progeny of tertiary grafted plants. Although the Cd content in the cuttings themselves was not significantly altered, continuous grafting markedly increased Cd accumulation within various tissues of the subsequent grafted generation plants. Furthermore, it contributed to a reduction in Cd bioavailability in the soil. In summary, continuous grafting suppressed the growth of the grafted cuttings but paradoxically enhanced both growth and Cd uptake capacity in their progeny. This study provides a theoretical foundation for employing grafting techniques to modulate crop physiological responses to Cd-contaminated soil. Subsequent research incorporating transcriptomic analysis is recommended to elucidate the molecular mechanisms underlying these transgenerational effects.