Variation in the number of pollen apertures has been widely described among and within angiosperm species. Apertures are weak points of the pollen wall where the pollen tube germinates. Pollen aperture heteromorphism (pollen grains with different numbers of apertures in a single individual) is common in flowering plants, whereas polymorphism (among-individual variation) is rare. Previous work o...

Some Malpighiaceae produce minute cleistogamous flowers in addition to showy chasmogamous flowers. Standard techniques fail to reveal how the cleistogamous flowers achieve self-fertilization. Fluorescence in longitudinal sections shows that the pollen germinates inside the indehiscent anther. The pollen tubes then grow down through the filament,. into the receptacle, up into the carpels, and in...

incompatibility in hazelnut (c. avellana l.) is the sporophytic type and under the control of a single s-locus with multiple alleles. compatibility of pollen-stigma in hazelnut is an important consideration in planning crosses in breeding program and in choosing pollinizers for orchard planting. in this study, fluorescence microscopy was used to determination of s-alleles and compatibility rela...

We screened for pollen-specific kinase genes, which are potential signal transduction components of pollen-pistil interactions, and isolated two structurally related receptor-like kinases (RLKs) from tomato, LePRK1 and LePRK2. These kinases are similar to a pollen-expressed RLK from petunia, but they are expressed later during pollen development than is the petunia RLK. The abundance of LePRK2 ...

In flowering plants, the process of pollen germination and tube growth is required for successful fertilization. A pollen receptor kinase from tomato (Solanum lycopersicum), LePRK2, has been implicated in signaling during pollen germination and tube growth as well as in mediating pollen (tube)-pistil communication. Here we show that reduced expression of LePRK2 affects four aspects of pollen ge...

While stigma anatomy is well documented for a good number of species, little information is available on the acquisition and cessation of stigmatic receptivity. The aim of this work is to characterize the development of stigma receptivity, from anthesis to stigma degeneration, in the pentacarpellar pear (Pyrus communis) flower. Stigma development and stigmatic receptivity were monitored over tw...

The pollen tube germinates from pollen and, during its migration, it perceives and responds to guidance cues from maternal tissue and from the female gametophyte. The putative female cues have recently been identified, but how the pollen tube responds to these signals remains to be unveiled. In a genetic screen for male determinants of the pollen tube response, we identified the pollen defectiv...

Mature pollen from most plant species is metabolically quiescent; however, after pollination, it germinates quickly and gives rise to a pollen tube to transport sperms into the embryo sac. Because methods for collecting a large amount of in vitro germinated pollen grains for transcriptomics and proteomics studies from model plants of Arabidopsis and rice are not available, molecular information...

In flowering plants, pollen germinates on the stigma and pollen tubes grow through the style to fertilize the ovules. Enzymatic production of reactive oxygen species (ROS) has been suggested to be involved in pollen tube tip growth. Here, we characterized the function and regulation of the NADPH oxidases RbohH and RbohJ (Respiratory burst oxidase homolog H and J) in pollen tubes in Arabidopsis ...

Pollen of Impatiens sultanii Hook F. germinates and forms tubes rapidly at 25 degrees C in a simple medium containing 111.0 ppm CaCl2, 13.6 ppm KH2PO4, and 1000 ppm boric acid. Calcium, potassium, and boron are essential for germination and tube growth, but sucrose is not required. Pollen tubes grow with equal rapidity in liquid medium or on a medium solidified with 1% agar. Tube growth rates a...