As pollen tubes grow through the pistil they are thought to perceive and respond to diverse signals. The tomato pollen-specific receptor kinases LePRK1 and LePRK2 might participate in signaling during pollen tube growth. We previously showed that the extracellular domain of LePRK2 interacts with a pollen protein, LAT52, before but not after pollen germination. To determine whether LePRK2 might ...

The fungicide phosphite was found to reduce pollen fertility in Australian and exotic species. In the perennial Dryandra sessilis the reduction was evident for a year after treatment with 2.5-10 gL,1 phosphite sprayed to run off. Pterochaeta paniculata, an annual, showed reduced pollen fertility in flowers that opened 16-30 days after spraying. The horticultural species Pelunia hybrida and Trad...

California valley oak is threatened by landscape alteration and failing recruitment in remnant stands. Its reproductive ecology is a key element of the seedling recruitment process. We first examine the mating system, to determine the extent of inbreeding in a population at Sedgwick Reserve, in Santa Barbara County. We then quantify variation in germination success and acorn size, evaluating th...

Plants have evolved many systems to prevent undesirable fertilization. Among these, incompatibility is a well-organized system in which pollen germination or pollen tube growth is inhibited in pistils. We previously found that a novel one-way pollen-stigma incompatibility response [unilateral incompatibility (UI)] occurred between two self-incompatible Brassica rapa plants, a Turkish line, and ...

A dynamic actin cytoskeleton is essential for pollen germination and tube growth. However, the molecular mechanisms underlying the organization and turnover of the actin cytoskeleton in pollen remain poorly understood. Villin plays a key role in the formation of higher-order structures from actin filaments and in the regulation of actin dynamics in eukaryotic cells. It belongs to the villin/gel...

Comparison of average crop yields with reported record yields has shown that major crops exhibit annual average yields three- to seven-fold lower than record yields because of unfavorable environments. The current study investigated the enhancement of pollen heat tolerance through expressing an Arabidopsis thaliana heat shock protein 101 (AtHSP101) that is not normally expressed in pollen but r...

The self-incompatibility system of the plant species Brassica is controlled by the S-locus, which contains S-RECEPTOR KINASE (SRK) and S-LOCUS PROTEIN11 (SP11). SP11 binding to SRK induces SRK autophosphorylation and initiates a signaling cascade leading to the rejection of self pollen. However, the mechanism controlling hydration and germination arrest during self-pollination is unclear. In th...

In flowering plants, the vegetative nucleus and the two sperm cells are proposed to form a functional assemblage, the male germ unit (MGU). Here, we describe the developmental pathway of MGU assembly in Arabidopsis and report two classes of mutations that affect the integrity and/or the positioning of the MGU in the mature pollen grain. In germ unit malformed (gum) mutants, the vegetative nucle...

Self-compatibility of local olive (Olea europaea L.) accessions and of the cultivars "Frantoio" and "Leccino" was investigated in Garda Lake area, northern Italy. Intercompatibility was determined for "Casaliva," "Frantoio," and "Leccino," as well as the effects of foliar Boron applications (0, 262, 525, or 1050 mg.L(-1)) applied about one week before anthesis on fruit set, shotberry set, and o...

Abstract Polyploids with odd-ploidy levels may play an important evolutionary role as they enable backcrosses their parental cytotypes. We chose the ploidy-variable Senecio carniolicus species group to address overarching question if pentaploid individuals, which occur at high frequencies in immediate contact zones of tetraploids and hexaploids, mediate effective interploidy gene flow. employed...