Occurrence and cytological mechanism of 2n pollen formation in a tetraploid accession of Ipomoea batatas (sweet potato)
Occurrence and cytological mechanism of 2n pollen formation in a tetraploid accession of Ipomoea batatas (sweet potato)
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DOI：
10.1093/jhered/93.3.185
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发表时间：
2002-05-01
影响因子：
3.1
通讯作者：
Orjeda, G
中科院分区：
文献类型：
--
作者：
Lopez-Lavalle, LAB;Orjeda, G
我们评估了4x加入的甘薯（Ipomoea batatas（L.）Lam. 4份2x材料用于2n花粉生产。约90%的基因型登录81.2（I。batatas，4x）产生的2n花粉频率不同。与此相反，没有L triloba基因型产生2n花粉。2n花粉的直径比n花粉的直径大约大30%（（3）根2），这使得其易于识别、测量和定量。大花粉的出现频率与二分体和三分体的出现频率之间的相关系数r = 0.93**，均达到极显著水平，表明大花粉为2n花粉。2n花粉生产者在后期II呈现平行或三极纺锤体排列（Y形），而不是正常的600交叉纺锤体取向。这两种异常的纺锤体构型产生了频率不同的二分体和三分体（13-67%），而不是四分体。偶尔一个中期II纺锤体的变化被发现与一个单一的融合纺锤体，这也形成了一个二分体。2n花粉频率与平行、融合和三极纺锤体排列频率之间的相关性（r = 0.89**）也达到极显著水平，表明这些异常的纺锤体构型与甘薯2n花粉的产生有关。当我们使用4x x 4x（2n）杂交来评估2n花粉在多倍体化中的效率时，所有后代都是4x，这表明4x基因型和它们的2n花粉生产者对应物之间存在可杂交性障碍。
We evaluated a 4x accession of Ipomoea batatas (L.) Lam. and four 2x accessions of Ipomoea triloba for 2n pollen production. Approximately 90% of the genotypes of accession 81.2 (I. batatas, 4x) produced 2n pollen with different frequencies. In contrast, none of the genotypes of L triloba produced 2n pollen. The diameter of the 2n pollen was approximately 30% ((3)root2) larger than that of the n pollen, making it easy to identify, measure, and quantify. The correlation (r = 0.93**) between the frequency of giant pollen and the frequency of dyads and triads was highly significant, strongly suggesting that the giant pollen grains were 2n pollen. The 2n pollen producers presented either a parallel or tripolar spindle arrangement (Y shaped) at anaphase II instead of the normal 600 crossed spindle orientation. These two abnormal spindle configurations produced dyads and triads, with different frequencies (13-67%), instead of tetrads. Occasionally a metaphase II spindle variation was found with a single fused spindle, which also forms a dyad. The correlation (r = 0.89**) between the frequency of 2n pollen and the frequency of parallel, fused, and tripolar spindle arrangements was also highly significant, suggesting that these abnormal spindle configurations are involved in the production of 2n pollen in L batatas. When we evaluated the efficiency of 2n pollen in polyploidization using 4x x 4x (2n) crosses, all progenies were 4x, suggesting the existence of barriers to crossability between 4x genotypes and their 2n pollen-producer counterparts.