The Effect of Brassinosteroid on Pollen Germination and Tube Growth in Three Dianthus Species

In this study, the effect of brassinosteroid on pollen germination and tube growth of  Dianthus calocephalus ,  Dianthus carmelitarum,  and  Dianthus deltoides  were investigated. Brassinosteroid treatment increased the germination rate in all species (except 0.05 mM in  Dianthus carmelitarum  and 2.5 mM in  D. deltoides ). However, a significant increase was only observed in  D. deltoides . The germination rate was highest after 0.25 mM BR treatment in  D. calocephalus , while the germination rate was highest after 0.5 mM BR treatment in  D. carmelitanum  and  D. deltoides . Brassinosteroid treatment increased the tube length in all species. However, a significant increase was only observed in  D. calocephalus . Also, tube length was maximum after 0.25 mM BR treatment in  D. calocephalus  and  D. carmelitarum , while tube length was maximum after 0.5 mM BR treatment in  D. deltoides . Brassinosteroid treatment increased the tube abnormality rate (except 0.25 mM in  D. deltoides ), insignificantly.