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Query: UMLS:C0277787 (stigma)
 13,352 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Inositol polyphosphates, such as inositol trisphosphate, are pivotal intracellular signaling molecules in eukaryotic cells. In higher plants the mechanism for the regulation of the type and the level of these signaling molecules is poorly understood. In this study we investigate the physiological function of an Arabidopsis (Arabidopsis thaliana) gene encoding inositol polyphosphate kinase (AtIPK2alpha), which phosphorylates inositol 1,4,5-trisphosphate successively at the D-6 and D-3 positions, and inositol 1,3,4,5-tetrakisphosphate at D-6, resulting in the generation of inositol 1,3,4,5,6-pentakisphosphate. Semiquantitative reverse transcription-PCR and promoter-beta-glucuronidase reporter gene analyses showed that AtIPK2alpha is expressed in various tissues, including roots and root hairs, stem, leaf, pollen grains, pollen tubes, the flower stigma, and siliques. Transgenic Arabidopsis plants expressing the AtIPK2alpha antisense gene under its own promoter were generated. Analysis of several independent transformants exhibiting strong reduction in AtIPK2alpha transcript levels showed that both pollen germination and pollen tube growth were enhanced in the antisense lines compared to wild-type plants, especially in the presence of nonoptimal low Ca(2+) concentrations in the culture medium. Furthermore, root growth and root hair development were also stimulated in the antisense lines, in the presence of elevated external Ca(2+) concentration or upon the addition of EGTA. In addition, seed germination and early seedling growth was stimulated in the antisense lines. These observations suggest a general and important role of AtIPK2alpha, and hence inositol polyphosphate metabolism, in the regulation of plant growth most likely through the regulation of calcium signaling, consistent with the well-known function of inositol trisphosphate in the mobilization of intracellular calcium stores.
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PMID:A role of Arabidopsis inositol polyphosphate kinase, AtIPK2alpha, in pollen germination and root growth. 1561 35

Tomato style is the pathway for pollen germination and pollen tubes growth from the stigma to the ovules where fertilization occurs. It is essential to supplying the nutrients for pollen tube growth and guidance for the pollen tubes. To our knowledge, style also regulates gametophytic self-incompatibility (SI) in tomato species. This study identified the metabolites and monitored the metabolic changes of self-incompatible and self-compatible tomato with self-pollinated or unpollinated styles by gas chromatography-mass spectrometry (GC-MS). A total of 9 classes of compounds were identified in SI and self-compatibility (SC) self-pollinated and unpollinated styles which included amino acids, sugars, fatty acids/lipids, amines, organic acids, alcohols, nitriles, inorganic acids and other compounds. The contents of d-Mannose-6-phosphate, Cellobiose, Myristic acid, 2,4-Diaminobutyric acid, Inositol and Urea were significantly decreased and the rest did not significantly change in SI styles. But change of metabolites content significantly happened in SC styles. In addition, among the total 9 classes of compounds, the different metabolites accounted for a different proportion in amino acids, sugars, amines, organic acids and alcohols compared SC and SI. The result indicated that the physiological changes of styles existed differences in SC and SI after self pollination.
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PMID:Dissect style response to pollination using metabolite profiling in self-compatible and self-incompatible tomato species. 2697 68