Calcium - a central regulator of pollen germination and tube growth

► A tip-focused calcium gradient is required for pollen tube growth. ► Calcium is involved in regulation of cytoskeleton and vesicle dynamics in pollen. ► We address potential mechanisms for decoding of calcium signals in pollen. ► We hypothesize that calcium-dependent kinases regulate ion channels in pollen. ► We discuss interconnections between different signaling networks in pollen tubes.