Influence of the Pistil on Pollen Tube Kinetics in Peach (Prunus persica)

Abstract

Pollen tube growth has been studied in peach and has been related to changes in the pistil structures which the pollen tube has to traverse in its way from the stigma down to the ovule. Growth of the pollen tubes along the pistil is not continuous. While pollen tubes reach the base of the style 7 days after pollination, fertilization does not take place until 12 days later. Pollen tubes stop for 5 days at the top of the obturator and they further stop for 3 days before entering the ovule. The pollen tube growth is heterotrophic; starch, present all along the pistilar tract at anthesis, vanishes as the pollen tubes pass by. Discontinuous pollen tube growth appears to be controlled by the pistil. At anthesis the pistil is not fully matured. Maturation of the pistil implies a number of secretory processes that occur in a basipetal way starting from the stigma down to the style and ending in the ovule. Some of these secretions at the stigma and the style are triggered by pollination; others appear to be a maturative stage of the pistil and are produced in a discrete way. The fact that the pollen tube depends on these secretions together with the fact that these secretions are not continuously produced confer upon the pistil a role of controlling pollen tube kinetics and point out that, for a successful fertilization, male gametophyte development and pistil maturation need to by synchronized.

Morphological, histological and ultrastructural changes in the olive pistil during flowering

“…The humid nature of the olive stigma is due to the secretion produced by the stigmatic papillae. The presence of stigma exudate, together with other factors (e.g., activity of enzymes such as esterases and phosphatases), determines its degree of receptivity at different moments (Knox 1984;Herrero and Arbeloa 1989;González et al 1995). This extracellular secretion undergoes major changes in its amount, composition and appearance under the electron microscope in the course of olive pistil development.…”

Fertilisation assessment and postzygotic development in several intra- and interspecific Prunus hybrids

“…At this time, as described for other Prunus spp ., both fertilisation (Hawker & Buttrose, 1980, Herrero & Arbeloa, 1989) and the first fall of flowers/fruitlets, which takes place two weeks after bloom (Eaton & Jamont, 1964 ;Pimienta & Polito, 1983), have already occurred . The clearing technique can be a very useful tool to assess fertilisation compared to the traditional sectioning procedures requiring embedding (Hughes & McCully, 1975) .…”

Molecular analysis of a pistil-specific gene expressed in the stigma and stylar cortex of Solanum tuberosum

“…Moreover, the pistil is thought to deliver compounds for the guidance of the pollen tubes through the stigma and transmitting tissue [3,7,8,15] and compounds that prevent pollen tube growth in the stylar cortex. Due to the physical penetration of non-aseptic pollen tubes, the pistil is wounded and, as a defense mechanism, should be able to produce, before pollination, compounds toxic for pathogens, such as proteinase inhibitors [ 1 ], defense-related thionins [6,11] and pathogenesis-related proteins [4,14,16,19,20].…”