Dynamic Changes of Ca²⁺ Distribution During the Process of Programmed Cell Death in Buds of Apical-bud-senescence Chestnut

PurposeIn this study, the dynamic changes of Ca²⁺ distribution during the process of programmed cell death (PCD) in bud of apical-bud-senescence chestnut X12 were studied, and the relationship between the dynamic changes of Ca²⁺ distribution and PCD were studied, too.

MethodThe dynamic changes of Ca²⁺ distribution during the process of programmed cell death in buds of apical-bud-senescence chestnut X12 were investigated with electromicroscopic-cytochemical methods of calcium antimonate.

ResultDuring the S1 period, the cell structure was normal, and Ca²⁺ mainly distributed on the cell wall and intercellular space, and little was seen in the cytoplasm and nucleus, and few in the vacuole. During the S2 period, some organelles were slightly degraded. The concentration of Ca²⁺ in intercellular space decreased, while the level of Ca²⁺ in cytoplasm and the vicinity of vacuolar membrane and nuclear membrane were increased. During the S3 period, cells disintegrated further, and cell wall, vacuole and nucleus degraded severely. The number of calcium particles on the cell wall and intercellular space become very rare, and the level of Ca²⁺ in cytoplasm, nucleus, and cracked vacuole and around the vacuole increased significantly. During the S4 period, cells degraded severely and Ca²⁺ particles appeared irregularly in cell, little on plasma membrane and cell wall, and a great deal of Ca²⁺ concentrated upon the ruptured tonoplast and the vacuolar fragments. During the S5 period, cytoskeleton were distorted because of degradation, organelles were degraded and ruptured, the Ca²⁺ aggregated with the degraded organelle fragments in lumps.

ConclusionThe dynamic changes of Ca²⁺ appeared in buds of apical-bud-senescence chestnut during the process of PCD, and Ca²⁺ was involved in the process of PCD. The congregation of Ca²⁺ in cytoplasm, nucleus and vacuole, might contribute to the PCD in buds of apical-bud-senescence chestnut X12.