A comparative ultrastructural analysis of exine pattern development in wild-type Arabidopsis and a mutant defective in pattern formation
A comparative ultrastructural analysis of exine pattern development in wild-type Arabidopsis and a mutant defective in pattern formation
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DOI：
10.1007/bf01282131
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发表时间：
1997-01-01
期刊：
影响因子：
2.9
通讯作者：
Makaroff, CA
中科院分区：
文献类型：
--
作者：
PaxsonSowders, DM;Owen, HA;Makaroff, CA
为了确定建立网状花粉壁模式所必需的因素，我们对T-DNA标记的拟南芥突变体进行了鉴定，该突变体的模式形成存在缺陷。本研究报告了突变体中花粉壁形成的超微结构与野生型植物花粉壁发育的比较结果。直到四分体早期，突变体的花粉壁发育与野生型相似。此时，野生型植物的小孢子质膜呈现规则的脊状和谷状图案。最初的孢粉沉积发生在山脊上，标志着小孢子形成的开始。相反，突变体的质膜表现为不规则的扁平突起和罕见的内陷。因此，没有形成野生的山脊和山谷的规律性格局。孢粉蛋白随机沉积在质膜上，聚集在子房壁上；它不固定在细胞膜上。我们的发现是，该突变阻止了质膜的正常内陷，并扰乱了壁形成过程中孢粉蛋白的正常沉积，表明该突变可能存在于负责图案形成的基因中。这些结果也提供了质膜在花粉壁模式的建立中起关键作用的直接证据。
In order to identify factors necessary for the establishment of the reticulate pollen wall pattern, we have characterized a T-DNA tagged mutant of Arabidopsis thaliana that is defective in pattern formation. This study reports the results of an ultrastructural comparison of pollen wall formation in the mutant to wall development in wild-type plants. Pollen wall development in the mutant par allels that of wild-type until the early tetrad stage. At this point in wild-type plants, the microspore plasma membrane assumes a regular pattern of ridges and valleys. Initial sporopollenin deposition occurs on the ridges marking the beginning of probacula formation. In contrast, the plasma membrane in the mutant appears irregular with flattened protuberances and rare invaginations. As a result, the wild-type regular pattern of ridges and valleys is not formed. Sporopollenin is randomly deposited on the plasma membrane and aggregates on the locule wall; it is not anchored to the membrane. Our finding that the mutation blocks the normal invagination of the plasma membrane and disrupts the proper deposition of sporopollenin during wall formation suggests that the mutation could be in a gene responsible for pattern formation. These results also provide direct evidence that the plasma membrane plays a critical role in the establishment of the pollen wall pattern.