9 Abstract Sexual plant reproduction depends on the pro10 duction and differentiation of functional gametes by the 11 haploid gametophyte generation. Currently, we have a 12 limited understanding of the regulatory mechanisms that 13 have evolved to specify the gametophytic developmental 14 programs. To unravel such mechanisms, it is necessary to 15 identify transcription factors (TF) that are p...

When young cells of Azotobacter vinelandii are impinged on membrane filters, washed free of carbon substrate, and placed on a mineral salts basal medium, the culture will proceed to encyst although at a slower rate than if n-butanol were supplied as a substrate. The endogenous cysts are depleted in polybeta-hydroxybutyrate and have a narrower intine but show an increased resistance to desiccati...

The CLAVATA3/ESR-RELATED (CLE) peptide signals are required for cell-cell communication in several plant growth and developmental processes. However, little is known regarding the possible functions of the CLEs in the anther. Here, we show that a T-DNA insertional mutant, and dominant-negative (DN) and overexpression (OX) transgenic plants of the CLE19 gene, exhibited significantly reduced anth...

background & aim: satureja khuzistanica jamzad. is an aromatic and medicinal perennial plant belongs to family mint (lamiaceae). it is also an iranian exclusive endemic species, its essential oil components are widely used in medicinal, culinary, and perfume industries. experimental: flowers were collected in 10 regions in khuzistan and lorestan provinces, iran at early anthesis during 2009...

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...

Plant type III polyketide synthases (PKSs) catalyze the condensation of malonyl-CoA units with various CoA ester starter molecules to generate a diverse array of natural products. The fatty acyl-CoA esters synthesized by Arabidopsis thaliana ACYL-COA SYNTHETASE5 (ACOS5) are key intermediates in the biosynthesis of sporopollenin, the major constituent of exine in the outer pollen wall. By coexpr...

BACKGROUND AND AIMS Hydration, rupture and exine opening due to the sudden and large expansion of intine are typical of taxoid-type pollen grains. A hemispheric outgrowth external to the exine was observed on Cupressus and Juniperus pollen grains before the intine swelling and exine release. However, the actual existence of this permanent or temporary structure and its precise role in pollen hy...

A comparative ultrastructural study of Araceae pollen walls was conducted for the first time. The results are based mainly on investigations by transmission electron microscopy of 101 species in 70 genera (out of a total of 105 genera), while pollen of 83 genera with 219 species were studied by scanning electron microscopy, generally without acetolysis. Special attention was given to Lemnaceae ...

The anther cuticle and microspore exine act as protective barriers for the male gametophyte and pollen grain, but relatively little is known about the mechanisms underlying the biosynthesis of the monomers of which they are composed. We report here the isolation and characterization of a rice (Oryza sativa) male sterile mutant, cyp704B2, which exhibits a swollen sporophytic tapetal layer, abort...