Morphological, Physiological, and Biochemical Characteristics in Leaves of A 4000-Year-Old Ginkgo biloba Tree Compared to Its Progeny and Grafted Plants

Ginkgo biloba L., renowned for its longevity and medicinal properties, accumulates abundant secondary metabolites like flavonoids and exhibits strong environmental adaptability. However, it remains uncertain whether grafted individuals and progeny from ancient G. biloba trees display phenotypic features associated with the focal ancient individual, or whether these features arise from rejuvenation-like transitions during propagation. Our study presents a comparative analysis of morphological, physiological, and biochemical characteristics in leaves of a 4000-year-old G. biloba tree, its progeny, and grafted plants. The old tree exhibited reduced leaf area and stomatal density, coupled with lower dry and fresh weights, indicative of a conserved metabolic state to enhance stress tolerance. Biochemical assessments revealed increased levels of trehalose, malondialdehyde, and hydrogen peroxide in the old tree's leaves, suggesting a heightened stress response mechanism. Conversely, the progeny and grafted plants exhibited higher contents of total flavonoids and flavonol glycosides, which are crucial for antioxidant activity and stress resistance. Notably, the old tree leaves had higher anthocyanin levels, potentially serving as an alternative protective compound. Our findings provide insights into the rejuvenation of old trees and the complex interplay between stress response and secondary metabolite profiles in G. biloba.