Plants being sessile by nature have developed sophisticated mechanisms to assist in their selection of mating partners. During a compatible pollination event, pollen grains that have landed on the stigmatic surface at the top of the pistil will adhere to the stigmatic cells, hydrate, germinate and form pollen tubes. The actively growing pollen tubes are often capable of penetrating the stigmati...

Our recent work used novel methods to localize and track discrete vesicle populations in pollen tubes undergoing oscillatory growth. The results show that clathrin-dependent endocytosis occurs along the shank of the pollen tube, smooth vesicle endocytosis occurs at the tip, and exocytosis occurs in the subapical region. Here, growth of tobacco and lily pollen tubes is examined in greater tempor...

Pollen tubes are the vehicle for sperm cell delivery to the embryo sac during fertilisation of Angiosperms. They provide an intriguing model for unravelling mechanisms of growing to extremes. The asymmetric distribution of lipids and proteins in the pollen tube plasma membrane modulates ion fluxes and actin dynamics and is maintained by a delicate equilibrium between exocytosis and endocytosis....

There is minimal information about the effect of heavy metals such as lead and copper on pollen grains and pollen tubes of fruit trees. Fruit set of these plants are affected by different environmental, biological, physical and chemical factors. If one of these factors be abnormal, pollination, fertilization and fruit set and orchard yield will decrease. In polluted cities, this phenomenon is a...

In pollen tubes, cytoskeleton proteins are involved in many aspects of pollen germination and growth, from the transport of sperm cells to the asymmetrical distribution of organelles to the deposition of cell wall material. These activities are based on the dynamics of the cytoskeleton. Changes to both actin filaments and microtubules are triggered by specific proteins, resulting in different o...

Microelectrodes, made from a Cl(-)-selective liquid ion exchanger previously used to measure putative Cl- fluxes in Lilium longiflorum pollen tubes, were characterized. The electrodes were poorly selective, possessing only about 10-fold selectivity for Cl- over other anions tested. They had only 2.4-fold selectivity for Cl- over the anionic form of the H+ buffer, MES, indicating that the electr...

Title of Document: POLLEN TUBES FAIL TO TARGET OVULE IN THE ABSENCE OF TWO CATION/PROTON EXCHANGERS IN ARABIDOPSIS Yongxian Lu Doctor of Philosophy, 2010 Directed By: Professor Heven Sze Department of Cell Biology & Molecular Genetics Flowering plant reproduction requires precise delivery of the sperm cells to the ovule by a pollen tube. Guiding signals from female cells are being identified, t...

Proper organization of the actin cytoskeleton is crucial for pollen tube growth. However, the precise mechanisms by which the actin cytoskeleton regulates pollen tube growth remain to be further elucidated. The functions of the actin cytoskeleton are dictated by its spatial organization and dynamics. However, early observations of the distribution of actin filaments at the pollen tube apex were...

The origin and rapid diversification of flowering plants has puzzled evolutionary biologists, dating back to Charles Darwin. Since that time a number of key life history and morphological traits have been proposed as developmental correlates of the extraordinary diversity and ecological success of angiosperms. Here, I identify several innovations that were fundamental to the evolutionary labili...

Pollen tube growth is a polarized growth process whereby the tip-growing tubes elongate within the female reproductive tissues to deliver sperm cells to the ovules for fertilization. Efficient and regulated membrane trafficking activity incorporates membrane and deposits cell wall molecules at the tube apex and is believed to underlie rapid and focused growth at the pollen tube tip. Rab GTPases...