Spatial and temporal distribution of cystoliths in mulberry leaves and their formation under the influence of phytohormones 6-BA and ABA

Mulberry (Morus spp.) has been studied to gain insight into cystolith formation, which is primarily composed of calcium carbonate (CaCO₃) deposits and commonly found in mulberry leaves. However, the effects of phytohormones on cystolith formation in mulberry and the origin of carbon within these structures remain poorly understood. This study utilized scanning electron microscopy, plant tissue sections, and silver nitrate staining techniques to comprehensively analyze the morphology of cystoliths in mulberry. Additionally, the distribution pattern of cystoliths was investigated, and mulberry seedlings were treated with 6-Benzylaminopurine (6-BA) and Abscisic acid (ABA). The results revealed that the density of cystoliths exhibited a normal distribution pattern, and there was a positive correlation between cystolith diameter and leaf age. Additionally, 6-BA significantly enhanced cystolith accumulation, whereas ABA had suppressive effects on cystolith formation in mulberry leaves. Furthermore, the concentration of applied phytohormones positively correlated with the yield of cystoliths. Based on these results, it is postulated that these phytohormones may modulate carbon absorption in mulberry by influencing stomatal conductance, thereby regulating cystolith formation. This research offers valuable insights into the underlying mechanisms driving mulberry cystolith formation and contributes to the optimal utilization of mulberry resources.