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Huan Xiong, Ping Chen, Zhoujun Zhu, Ya Chen, Feng Zou, and Deyi Yuan

in anther development between the male sterility line ‘X1’ and the male-fertile half-sib family plant ‘Z720’ ( Figs. 3 and 4 ), specifically with regard to the tapetum and vascular bundle of the anther. Pollen development in C. oleifera began at

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Weiping Zhong, Zhoujun Zhu, Fen Ouyang, Qi Qiu, Xiaoming Fan, and Deyi Yuan

function). From the outer to the inner layers, the anther wall includes epidermis, endothecium, middle layer, and tapetum. During anther development, different anther wall cell layers undergo different developmental stages, such as vacuolation of epidermal

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Cheng-Jung Hu, Nean Lee, and Yung-I Lee

malfunction of anther tissue. The sporophytic anther tissues play important roles in pollen development, not only by providing physical support but also by supplying signals and materials necessary for pollen development. Especially, the tapetum, the most

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Ting Liao, Guobin Liu, Liqin Guo, Ye Wang, Yanwu Yao, and Jun Cao

). In late August, the middle layer and tapetum cells were distinct from the epidermal cells under morphological observation. ( Fig. 2B ). In September, the microsporangium continued to grow, and the male cones developed rapidly. The male cones were pink

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Dongmei Wei, Huimin Xu, and Ruili Li

= pistillate flower, SF = staminate flower, SC = sporogenous cell, T = tapetum; bars: ( A, C ) 10 mm, ( B ) 5 mm, ( D ) 1 mm, ( E, F, G, H ) 20 μm. Following transverse sectioning, R. communis anthers from different developmental stages could be divided into

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Elina Yankova-Tsvetkova, Ivanka B. Semerdjieva, Rozalia Nikolova, and Valtcho D. Zheljazkov

’ classification ( Davis, 1966 ). It consisted of four layers: an epidermis, an endothecium, one middle layer, and a tapetum. At the beginning of anther’s ontogenesis, the anther’s wall layers were almost similar in shape and size ( Fig. 1A ) but after the

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Fengxia Shao, Sen Wang, Juan Chen, and Rongyan Hong

it contained four layers: the epidermis, endothecium, middle layer, and tapetum (from the outermost to the innermost layers). The middle layer was a single layer of cells. During the meiosis of the microsporocyte, cells in the middle layer already

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Alan G. Smith and Kenneth J. McNeil

The sporophytic tissue of the anther and, in particular, the tapetum, a cell layer surrounding the pollen sac, is know to be essential for the production of pollen. The isolation and characterization of the gene 92B from tomato that encodes an extracellular glycine rich protein (GRP) has been used to further elucidate the role of the tapetum in pollen development. RNA from the 92B gene accumulates exclusively in the tapetum. Polyclonal antibodies raised against the 92B GRP detect four proteins in stamens with microspores beginning meiosis. In pollen extracts, the antibodies detect a single protein. Expression of the tomato 92B gene in transgenic tobacco indicates that the four protein products are derived from only the 92B gene. The 92B GRP is localized to the tapetum, the callose wall of microspore mother cells, the exine (outer wall) of mature pollen, and orbicules. Orbicules are globular bodies derived from tapetal material that form on the tapetum wall and line the exterior of the pollen sac. Expression of 92B antisense RNA resulted in a significant decrease of 92B RNA and protein levels in transgenic tomatoes. This reduction was correlated with a decrease in pollen germination and an abnormal exine morphology. The function of the 92B protein in pollen development and function will be discussed.

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Jon T. Lindstrom, Chih-Hsien Lei, and William R. Woodson

Petunia hybrida pollen accumulates significant levels of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) late in development. This pollen ACC is thought to play a role in the rapid burst of ethylene produced by pollinated pistils. To investigate this further, we have expressed the ACC deaminase gene product from Pseudomonas in transgenic petunias under the control of three different promoters including CaMV-35S, LAT52, and TA29 directing construction expression, pollen-specific expression and tapetum-specific expression, respectively. Several transgenic plants expressing the LAT52-ACC deaminase gene exhibited significant reduction of ACC in pollen. Two independent transformants contained only trace amounts of ACC in pollen. In contrast, the other promoters did not lead to reduced ACC in pollen. Pollination of wild-type pistils with pollen from LAT52-ACC deaminase plants elicited increased ethylene similar to wild-type pollen. Fecundity was unaffected by the reduction in pollen ACC content. Taken together, we conclude pollen-borne ACC is not the elicitor of pollination-induced ethylene production by pistils.

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Chun-Qing Sun, Zhi-Hu Ma, Guo-Sheng Sun, Zhong-Liang Dai, Nian-jun Teng, and Yue-Ping Pan

after their nucleus division ( Fig. 4B ). At the vacuolated uninucleate pollen stage, the tapetum began to lose the wall and intrude into the locular space with the cytoplasm fusing from the periplasmodium around the microspore in the late uninucleate