Thepollen of hazels can genninat natuIally, but later itS POllen tUbes StOp growing, the malegametOphyte in the tube withers gIadually then in the end the tUbe dies.

• 榛子的花粉能正常萌发，但之后，花粉管停止生长，花粉管中的雄配子体逐渐萎缩，最后花粉管死亡；