A3 male sterile cytoplasm in sorghum (Sorghum bicolor L. Moench) is from IS1112C. Among the seven kinds of cytoplasmic male sterility (CMS) in sorghum, the sterility in A3 CMS is most stable, and very difficult to restore. In this study A3 male sterile line Jingliang 5 and corresponding maintainer B3 Jinliang 5 were used to study the process of A3 CMS anther development and analyze the chromosomal behaviors of meiosis during microspore formation, in order to understand the basis of A3 CMS genesis. The results showed that differing from that in A1 and A2 CMS, the meiosis of pollen mother cell (PMC) in A3 Jinliang 5 was completed normally. No abnormal meiotic behaviors were observed compared to its corresponding maintainer B3 Jinliang 5. In sporogenous cell stage, premeiotic interphase and meiosis stage, no abnormal phenomena were found. Tetrad separated normally in paraffin-embedded A3 male sterile line anther section observation. But in pollen mature stage deformed pollens were observed and it was in this stage, i.e. about 7 days before anthesis, the normal development of microspores was affected, sucrose-starch metabolic pathway was blocked and no starch particles were deposited on intine of A3 CMS pollens, leading to unviable pollen formation.
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图版Ⅰ说明
A3晋梁 5号和 B3晋梁 5号花药发育过程的解剖结构(1~8)、小孢子减数分裂行为(9~16)和花粉粒碘染色观察(17~20)。
1~8：A3/B3晋粱 5号花药石蜡包埋切片。1：A3晋粱 5号造孢细胞时期(×200)；2：A3晋粱 5号减数分裂前间期(×132)；3：A3晋粱 5号
减数分裂中后期Ⅰ(×100)；4：B3晋粱 5号幼龄花粉粒时期，绒毡层开始退化(×100)；5：A3晋粱 5号单核花粉粒时期，部分花粉粒皱缩，绒
毡层退化解体(×100)；6：A3晋粱 5号成熟花粉粒皱缩变形，药室合并（×50）；7：B3晋粱 5号单核花粉粒，部分花粉粒出现变形(×100)；8：
B3晋粱 5号成熟花粉粒，药室合并（×50）。
9~16：A3晋粱 5号小孢子减数分裂（×330）。9：双线期Ⅰ；10：终变期Ⅰ；11：中期Ⅰ；12：后期Ⅰ；13：末期Ⅰ；14：中期Ⅱ；15：
后期Ⅱ；16：四分体。
17~20：A3/B3晋粱 5号花药花粉粒 1% I2-KI染色 (×50)。17：B3晋粱 5号开花前 7 d花粉粒；18：B3晋粱 5号开花前 1 d花粉粒；19：
A3晋粱 5号开花前 7 d花粉粒；20：A3晋粱 5号开花前 1 d花粉粒。
Explanation of PlateⅠ
Anatomical structure of anther development in A3 Jinliang 5 and B3 Jinliang 5 (1–8), chromosome patterns in microspore meiosis (9–16), and
pollen observation after I2-KI staining (17–20).
1–8: A3/B3 anther section by paraffin-embedding. 1: Sporogenous cell period of A3 Jinliang 5 (×200); 2: Premeiosis Interphace of A3 Jinliang 5 (×132); 3:
Meiotic anaphase of A3 Jinliang 5 (×100); 4: Pollen development of B3 Jinliang 5, degeneration of taptum (×100); 5: Uni-nucleate pollen stage of A3 Jinliang
5, shrinkage of part of pollen grains and degeneration of taptum (×100); 6: Shrinked and deformed mature pollen grains of A3 Jinliang 5, combination of anther
chambers (×50); 7: Uni-nucleate pollen grains of B3 Jinliang 5, part of the pollen grains deformed (×100); 8: Mature pollen grains of Jinliang 5 with
combination of anther chambers (×50).
9–16: Microspore meiosis of Jinliang 5 (×330). 9: DiplonemaⅠ; 10: DiakinesisⅠ; 11: MetaphaseⅠ; 12: AnapaseⅠ; 13: TelophaseⅠ; 14: Metaphase Ⅱ;
15: Telophase Ⅱ; 16: Tetrad.
17–20: A3/B3 Jinliang 5 pollen grains stained with 1% I2-KI (×50). 17: Pollen grains of B3 Jinliang 5, 7 days before anthesis; 18: Pollen grains of B3
Jinliang 5, 1 day before anthesis; 19: Pollen grains of A3 Jinliang 5, 7 days before anthesis; 20: Pollen grains of B3 Jinliang 5, 1 day before anthesis.
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仪治本等：高粱 A3细胞质雄性不育发生的细胞学观察及分析 图版Ⅰ
YI Zhi-Ben et al.: Cytolgical Observation and Analyses of A3 Cytoplasmic Male Sterility PlateⅠ
in Sorghum