Abstract:

Calcium (Ca²⁺) signaling has been implicated in pollen germination and pollen tube growth. To date, however, we still know very little about how exactly Ca²⁺ signaling links to various physiological subcellular processes during pollen germination and pollen tube growth. Given that Ca²⁺ signaling is tightly related to the cytosolic concentration and dynamics of Ca²⁺, it is vital to trace the dynamic changes in Ca²⁺ levels in order to decode Ca²⁺ signaling. Here, we demonstrate that G‐CaMP5 serves well as an indicator for monitoring cytosolic Ca²⁺ dynamics in pollen cells. Using this probe, we show that cytosolic Ca²⁺ changes dramatically during pollen germination, and, as reported previously, Ca²⁺ forms a tip‐focused gradient in the pollen tube and undergoes oscillation in the tip region during pollen tube growth. In particular, using G‐CaMP5 allowed us to capture the dynamic changes in the cytosolic Ca²⁺ concentration ([Ca²⁺]_cyt) in pollen tubes in response to various exogenous treatments. Our data suggest that G‐CaMP5 is a suitable probe for monitoring the dynamics of [Ca²⁺]_cyt in pollen cells.