The effect of anther-derived substances on pollen function was studied using pollen produced by in vitro culture of immature pollen of tobacco (Nicotiana tabacum L.) and petunia (Petunia hybrida). Addition of conditioned medium consisting of diffusates from in situ matured pollen strongly increased pollen germination frequency and pollen tube growth, as well as seed set after in situ pollinatio...

This study was carried out in order to determine the effects of boron and cold stress on pollen germination of almond hybrids in vitro culture, two different media including the absence and presence of boron (0 mg/l, and 100 mg/l) in 10% sucrose and 1% agar medium at 24°C in dark conditions. The results showed that different treatments had a significant effect on the germination percentage. The...

Pollen-stigma interactions are essential for pollen germination. The highly regulated process of pollen germination includes pollen adhesion, hydration, and germination on the stigma. However, the internal signaling of pollen that regulates pollen-stigma interactions is poorly understood. KINβγ is a plant-specific subunit of the SNF1-related protein kinase 1 complex which plays important roles ...

Previous genetic studies have revealed that a pollen-specific calmodulin-binding protein, No Pollen Germination 1 (NPG1), is required for pollen germination. However, its mode of action is unknown. Here we report direct interaction of NPG1 with pectate lyase-like proteins (PLLs). A truncated form of AtNPG1 lacking the N-terminal tetratricopeptide repeat 1 (TPR1) failed to interact with PLLs, su...

The pollen of five diploid and two tetraploid guayule (Parthenium argentatum Gray) plants was cultured on nutrient media. It was observed that guayule pollen is released as tetrads of spores which will not ger­ minate on the media unless they are separated into individual pollen grains. For each plant, the results of the germination tests varied with the day and the time of day of the pollen co...

The artificial germination of plant pollens has met with varying success. As a whole, the pollen of the Gramineae has proved very difficult to germinate. While experiments with the pollen of many plants have resulted not only in ready germination but in satisfactory methods of preserving the pollen for considerable periods of time, the results with many of the Gramineae have been far from satis...

Iran is one of the main date (Phoenix dactylifera) producing countries in the world. however, little information is available on the pollen viability and favorable storage conditions of Iranian male date cultivars. This study was conducted to estimate the best in vitro pollen germination of three male date palm cultivars, `Ghanami’, `Samsmavi’ and `Gheibani’ using various doses of boric acid (0...

Arabidopsis exocyst subunit SEC3A has been reported to participate in embryo development. Here we report that SEC3A is involved during pollen germination. A T-DNA insertion in SEC3A leads to an absolute, male-specific transmission defect that can be complemented by the expression of SEC3A coding sequence from the LAT52 promoter or SEC3A genomic DNA. No obvious abnormalities in the microgametoge...

Calmodulin (CaM), a ubiquitous multifunctional calcium sensor in all eukaryotes, mediates calcium action by regulating the activity/function of many unrelated proteins. Although calcium and CaM are known to play a crucial role in pollen germination and pollen tube growth, the proteins that mediate their action have not been identified. We isolated three closely related CaM-binding proteins (NPG...

Pollen from three S-genotypes of Nicotiana alata was grown in vitro in the presence of S-glycoproteins isolated from styles of the same three genotypes. Pollen germination was not affected by the presence of the S-glycoproteins, but pollen tube growth of all genotypes was inhibited. S2 pollen was preferentially inhibited by the S2-glycoprotein and S3 pollen by the S3-glycoprotein. The S6-glycop...