High impact information on Flowers

• A pollen tube growth stimulatory glycoprotein is deglycosylated by pollen tubes and displays a glycosylation gradient in the flower [1].
• Pollen tube cells elongate on an active extracellular matrix in the style, ultimately guided by stylar and embryo sac signals [2].
• Germinating grass pollen also secretes an unusual expansin that loosens maternal cell walls to aid penetration of the stigma by the pollen tube [3].
• We report that a K(+) channel of the Shaker family in Arabidopsis, SPIK, plays an important role in pollen tube development [4].
• An Arabidopsis thaliana Rho family GTPase, ROP1, controls pollen tube growth by regulating apical F-actin dynamics [5].

Biological context of Flowers

• Ca(2+) signals are thought to play important roles in plant growth and development, including key aspects of pollen tube growth and fertilization [6].
• We found that a approximately 50% increase in the total profilin pool was necessary to half-maximally inhibit pollen tube growth, whereas a approximately 100% increase was necessary for half-maximal inhibition of cytoplasmic streaming [7].
• The pollen tube apical region undergoes a 46% increase in cell volume after addition of 100% water (v/v), and there is an average 7-fold increase in PA [8].
• Antisense phenotypes reveal a role for SHY, a pollen-specific leucine-rich repeat protein, in pollen tube growth [9].
• As part of the almond breeding programme at IRTA, we investigated the S genotypes of several cultivars using a combination of RNase zymograms, testcrosses, pollen-tube growth analysis and molecular identification by PCR analysis [10].

Anatomical context of Flowers

• The VGD1 protein was distributed throughout the pollen grain and pollen tube, including the plasma membrane and cell wall [11].
• An ankyrin repeat-containing protein, characterized as a ubiquitin ligase, is closely associated with membrane-enclosed organelles and required for pollen germination and pollen tube growth in lily [12].
• The actin cytoskeleton plays an important role in the growth of pollen tube [13].
• BACKGROUND: and Aims Free-flowing surface exudates at the stigmatic (wet versus dry stigma) and adaxial epidermis at the site of angiospermy in carpels of Chloranthaceous species have been proposed to comprise a continuous extracellular matrix (ECM) operating in pollen tube transmission to the ovary [14].
• Cytoskeletal organisation and modification during pollen tube arrival, gamete delivery and fertilisation in Plumbago zeylanica [15].

Associations of Flowers with chemical compounds

• We have purified a glycoprotein, TTS, from tobacco stylar transmitting tissue, which supports pollen tube growth between the stigma and the ovary [16].
• Chemical composition, specific enzyme degradations, and immunolabeling data support the idea that this molecule required for pollen tube adhesion is a pectic polysaccharide [17].
• Regulation of pollen tube growth is known to involve alterations in intracellular calcium levels and phosphoinositide signaling, although the mechanisms involved are unclear [18].
• One of these, the Cys-rich protein LAT52, was known to be essential during pollen hydration and pollen tube growth [19].
• The Cl(-) channel blockers 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) and 5-nitro-2-(3-phenylpropylamino)benzoic acid completely inhibited tobacco pollen tube growth at 80 and 20 microM, respectively [20].

Gene context of Flowers

• The whole set of data supports the hypothesis that functional expression of SPIK plays a role in K(+) uptake in the growing pollen tube, and thereby in tube development and pollen competitive ability [4].
• VGD1 was expressed specifically in pollen grain and the pollen tube [11].
• Functional interruption of VGD1 reduced PME activity in the pollen to 82% of the wild type and greatly retarded the growth of the pollen tube in the style and transmitting tract, resulting in a significant reduction of male fertility [11].
• In the context of the ovule, MYB98 is expressed exclusively in the synergid cells, and mutations in this gene affect the female gametophyte specifically. myb98 female gametophytes are affected in two unique features of the synergid cell, pollen tube guidance and the filiform apparatus, but are otherwise normal [21].
• Pollen tube localization implies a role in pollen-pistil interactions for the tomato receptor-like protein kinases LePRK1 and LePRK2 [22].

Analytical, diagnostic and therapeutic context of Flowers

• Immunofluorescence analysis of pollen tubes revealed that clathrin localises to the plasma membrane at the apex of the pollen tube tip, which is consistent with high levels of clathrin-mediated membrane recycling [23].
• When the pollen tube enzyme was solubilized with 0.5% (v/v) Triton X-100 and was incubated with PA-OGA and UDP-galacturonic acid (UDP-GalUA), successive transfer activity of more than 10 GalUAs from UDP-GalUA to the nonreducing end of PA-OGA was observed by diethylaminoethyl high-performance liquid chromatography [24].
• However, each of them has certain disadvantages, which led to research into the development of novel alternative systems such as infiltration, electroporation of cells and tissues, electrophoresis of embryos, microinjection, pollen-tube pathway, silicon carbide- and liposome-mediated transformation [25].

References