نتایج جستجو برای: exine
تعداد نتایج: 341 فیلتر نتایج به سال:
BACKGROUND AND AIMS Ultraviolet-B (UV-B) radiation effect on reproductive parts of the plants has received little attention. We studied the influence of UV-B radiation on flower and pollen morphology, pollen production and in vitro pollen germination and tube growth of six genotypes of soybean (Glycine max). METHODS Soybean genotypes were investigated by growing them under four levels of biol...
During encystment of Azotobacter vinelandii, a family of alkylresorcinols (ARs) and alkylpyrones (APs) are synthesized. In the mature cyst, these lipids replace the membrane phospholipids and are also components of the layers covering the cyst. In this study, A. vinelandii strains unable to synthesize ARs were isolated after mini-Tn5 mutagenesis. Cloning and nucleotide sequencing of the affecte...
Rice reproductive development is sensitive to high temperature and soil nitrogen supply, both of which are predicted to be increased threats to rice crop yield. Rice spikelet development is a critical process that determines yield, yet little is known about the transcriptional regulation of rice spikelet development in response to the combination of heat stress and low nitrogen availability. He...
Cucurbitaceae contain c. 800 species in 130 genera and are among the economically most important families of plants. We inferred their phylogeny based on chloroplast DNA sequences from two genes, one intron, and two spacers (rbcL, matK, trnL, trnL-trnF, rpl20-rps12) obtained for 171 species in 123 genera. Molecular data weakly support the traditional subfamilies Cucurbitoideae (111 genera) and ...
BACKGROUND AND AIMS The extant species of the seed plant group Gnetales (Ephedra, Gnetum and Welwitschia) have been considered a remnant of a much greater, now extinct, diversity due to the pronounced differences in form and ecology among the genera. Until recently, this hypothesis has not been supported by evidence from the fossil record. This paper adds to the expanding information on Gnetale...
To identify factors that are required for proper pollen wall formation, we have characterized the T-DNA-tagged, dex1 mutation of Arabidopsis, which results in defective pollen wall pattern formation. This study reports the isolation and molecular characterization of DEX1 and morphological and ultrastructural analyses of dex1 plants. DEX1 encodes a novel plant protein that is predicted to be mem...
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