haploid plant per floret (Devaux, 1988). Androgenesis induction in microspores may be affected by various An efficient doubled-haploid production technology that induces factors which cause low induction efficiency and by gehomozygosity can greatly reduce the time and cost of cultivar developnotype dependence (Dunwell, 1985). Most advances toment. Low efficiency of doubled-haploid production pr...

The aim of this work was to carry out the reproductive studies on Brazilian accessions of ipecac, Psychotria ipecacuanha. It presented heterostyly, with brevistylous and longistylous flowers. The pollen development was observed from the sections of the anthers embedded in resin. Anther development was normal as usually observed in dicotyledones, displaying four layers: outer epidermis, endothec...

background:  stresses such as heat shock, starvation, or osmotic is essential to lead isolated microspores towards embryogenesis. despite the effectiveness of stresses in embryogenesis, they exert adverse effects on metabolism and growth of the regenerated plants.objectives: the effects of heat shock and 2,4-d treatment on total protein content of treated microspores, morphological and physiolo...

A simple procedure is described for the mechanical isolation of protoplasts of unfertilized and fertilized barley egg cells from dissected ovules. Viable protoplasts were isolated from ~75% of the dissected ovules. Unfertilized protoplasts did not divide, whereas almost all fertilized protoplasts developed into microcalli. These degenerated when grown in medium only. When cocultivated with barl...

We identified the Arabidopsis MALE STERILITY1 (MS1) gene by transposon-mediated mutagenesis. In the transposon-inserted allele ms1-8, normal immature microspores separated from tetrads, but their subsequent maturation was abnormal: the outer layer of the microspore was absent, and both the microspore and the tapetal layer gradually became vacuolated. Empty locules resulted. The MS1 gene was exp...

Plant growth regulator (PGR) crosstalk and interaction with the plant's genotype and environmental factors play a crucial role in microspore embryogenesis (ME), controlling microspore-derived embryo differentiation and development as well as haploid/doubled haploid plant regeneration. The complexity of the PGR network which could exist at the level of biosynthesis, distribution, gene expression...

In flowering plants, the male gametophyte, the pollen, develops in the anther. Complex patterns of gene expression in both the gametophytic and sporophytic tissues of the anther regulate this process. The gene expression profiles of the microspore/pollen and the sporophytic tapetum are of particular interest. In this study, a microarray technique combined with laser microdissection (44K LM-micr...

the structure and histogenesis of the stigma of datura stramonium was investigated by light and scanning electron microscopy to determine the developmental origin of the transmitting tissue and “wet stigma”. four developmental stages were defined on the basis of bud length. stage one, the histogenesis stage, was comprised of buds 2-15 mm in length. stage two, signified by the growth and develop...