Shandong Branch of National Vegetable Improvement Center，Shandong Key Laboratory of Greenhouse Vegetable Biology，Huanghuai Region Vegetable Scientific Observation and Experiment Station，Ministry of Agriculture and Rural Affairs （Shandong），Institute of Vegetables，Shandong Provincial Academy of Agricultural Sciences，Jinan 250100，Shandong，China
Abstract：In order to definite flower organ morphology，anther and pollen abortive period of Welsh onion（Allium fistulosum L.）male sterile strain and its cytological mechanism，this study adopted organ morphology observation，pollen vigour test，paraffin section，scanning electron microscope and transmission electron microscope analysis，etc. methods to conduct observation on exported and still fresh Welsh onion male sterile line FCY-A；anther development process and cytological characteristics of its maintainer line FCY-B.The results showed that the anther of Welsh onion maintainer line FCY-B was well-stacked，normally cracking and releasing pollen．The pollen had stronger viability．And individual pollen grain was superelongate in shape with single groove and rough，brain-like exine ornamentation. Its surface was covered with varying depths of micro-holes．While，the pollen of sterile line FCY-A was shriveled. No pollen was seen on the surface. Its pollen had no viability．The pollen grains were adhered to each other and overlap．No normal single pollen grains were seen．Most of the pollen grains collapsed and deformed with more surface impurities．It was not smooth and had a warty protrusion．The abortion period of sterile line FCY-A began in the tetrad period．The cause of abortion was abnormal enlargement of tapetum cells．The delayed programmed cell death could not provide important nutrient substance for microspore development，leading to microspore vacuolation，abnormal development of microspore outer wall and pollen abortion．
