细胞质雄性不育（CMS）机理的细胞学研究在许多作物上已有报道，如拟南芥、大豆、水稻、小麦等，但在国内至今未见关于洋葱的此类报道。利用光镜和透射电镜对洋葱不育系63A和保持系63B进行花药发育过程中显微结构和超微结构观察，结果表明，不育花药花粉母细胞时期，花粉母细胞发育正常，花粉囊形状不规则，绒毡层发育迟缓。四分体时期，四分体形成正常，中层严重退化，绒毡层与药室壁完全脱离，细胞质浓缩、空泡化。利用DNA梯度技术发现不育系绒毡层细胞提早发生程序性死亡。小孢子发育时期，小孢子细胞质发生浓缩、降解，绒毡层完全解体。推测不育系小孢子败育与中层、绒毡层提前衰退有关。
Cytological studies of cytoplasmic male-sterility (CMS) mechanism have been reported in several crops of Arabidopsis, soybean, rice, wheat etc. To date no report on CMS studies in onion (Allium cepa L.) is available in China. By using the technology of light microscopy and transmission electron microscopy, microstructural and ultrastructural observations of male-sterility line 63A and maintainer line 63B anthers were done during their development in onion (Allium cepa L.). The results indicated that in the male sterile anther, pollen sacs were formed irregularly and the tapetum formation was incomplete at the pollen-mother cell stage. The middle layer was degenerated completely and collapsed into a thin layer, the tapetal cells become vacuolated and dissociated from the pollen sac wall, followed by condensation of the tapetal cytoplasm at the tetrad stage. Meanwhile, it was presumed that the tapetal cells in male sterile anther underwent premature programmed cell death (PCD) based on the DNA ladder. At the developing microspore stage, the complete disintegration of cytoplasm in the microspore was observed. It is suggested that the microspore abortion in male-sterile anther would be attributed to premature degeneration of middle layer and tapetum.
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李园园等：洋葱 63A细胞质雄性不育与绒毡层的提早衰退有关 图版Ⅰ
LI Yuan-Yuan et al.: Cytoplasmic Male-Sterility of Onion (Allium cepa L.) 63A Is Associated with
Premature Degeneration of the Tapetum PlateⅠ
a t
pm
b
pm
d
t
Tds
c t ml
Tds
e t
ml
t
f
msp
h
ex
g
po
Explanation of PlateⅠ
a–h: Light-microscopic observations of onion (Allium cepa L.) male-sterile line 63A and maintainer line 63B anthers at four developmental stages.
a ,c ,e and g: Male-fertile anther locules ; b ,d ,f and h: Male-sterile anther locules ; a and b: Pollen-mother cell stage (×40); c and d: Tetrad stage
(×40); e and f: Microspore stage (×40); g and h: Pollen grains stage (×40). pm: pollen-mother cell. po: pollen. t: tapetum. ml: middle layer Tds:
tetrad. ex: exine
1
李园园等：洋葱 63A细胞质雄性不育与绒毡层的提早衰退有关 图版Ⅱ
LI Yuan-Yuan et al.: Cytoplasmic Male-Sterility of Onion (Allium cepa L.) 63A Is Associated with
Premature Degeneration of the Tapetum PlateⅡ
a ex
Nu
ER
b
mt
Nu
ER
Vc
c
Nu
d ex
cp
2
e mt
ch
f
ER
Nu
i ex
cp
t
g
cp
h
msp
t
Explanation of PlateⅡ
a–i: Transmission electron micrographs of onion male-sterile line 63A and maintainer line 63B anther at the tetrad stage, the microspore stage and
the pollen stage. a and g: Transmission electron micrographs of the fertile anther at the microspore stage; a: Uni-nucleate microspore (×48000); g:
The tapetum and the microspore (×36000); b–f and h–i: Transmission electron micrographs of the male sterile anther at the tetrad stage, the
microspore stage and the pollen stage ; b: The abnormal uni-nucleate microspore (×36000); c: Bi-nucleate pollen (×29000) ; d and I: The
formation of the exine and the disintegration of the pollen (×10000) ; e: Shrinkage of the tapetal cell, condensation of chromatin and persistence of
mitochondria at the tetrad stage (×72000); f: Swelling of the endoplasmic reticulum at the tetrad stage (×10000); h: The tapetum in sterile anther
released no component and the microspore wall unformed. ex: exine. Nu: nucleus. ER: endoplasmic reticulum. rb: robisome. vc: vacuole. mt:
mitochondria. msp: microspore. ch: chromatin. cp: component.