Characteristics of pollen germination and pollen tube growth in in vivo sand pear styles

Two pear cultivars with different self incompatible strength,Housui and Kikusui,were self pollinated and Housui was pollinated with the pollen of Kikusui,respectively.Following characteristics of pollen germination and pollen tube growth were observed with fluorescence microscope.Both the self and cross pollinated pollen grains on the stigma had a high percentage of pollen germination that was up to over 95%,and there was no distinct difference between them.However,the speed of pollen tube growth and the place where pollen tube growth arrested of both in in vivo style were different.The pollen tube growth of Housui self pollinated completely arrested at the upper one third of the style,which behaved strong self incompatibility.While the arrest of pollen tube growth of Kikusui self pollinated most occurred at the upper one third of the style,only some pollen tubes still grew to the style bottom,which made Kikusui behave as a weakly self incompatible cultivar.Although some cross pollinated pollen tube growth arrested in the styles,lots of pollen tubes still grew to the style bottom,which behaved cross compatibility.The self pollinated pollen tubes in the styles often followed curve,swell and front deformation before arresting growth,but not the cross pollinated ones in the styles.