Figure 3.

Effect of External Ca²⁺ and K⁺ on Pollen Tube Growth.

(A) Effect of external Ca²⁺ on pollen tube length. Pollen grains were germinated on solidified medium containing 1 mM K⁺ and the indicated concentrations of Ca²⁺. Each data bar represents the means ± se of three replicates. More than 80 pollen tubes were measured for the average pollen tube length in each replicate. Asterisks indicate significant difference from Columbia (Col) at P < 0.05 by Student's t test.

(B) Effect of external K⁺ on pollen tube length. Pollen grains were germinated on solidified medium containing 20 mM Ca²⁺ and the indicated concentrations of K⁺. Each data bar represents the means ± se of three replicates. The average length of more than 80 pollen tubes was in each replicate. Asterisks indicate significant difference from Columbia (Col) at P < 0.05 by Student’s t test.