Environmental factors influence plant development and in particular the reproductive system is sensitive to extreme temperature conditions causing reduction in fertility. Previously we reported that a short period of cold stress evokes the formation of diploid pollen by interfering with the organization of the radial microtubule array at the telophase II tetrad stage, and consequently leading t...

Water deficit during male meiosis in wheat (Triticum aestivum L.) causes pollen sterility. With a view to identifying the internal trigger for this failure, it was found that water stress specifically impairs the activities of vacuolar and cell-wall invertases in anthers prior to the arrest of pollen development. The enzymes are affected only when water deficit occurs around meiosis. Three inve...

The pollen-stigma interaction of self-incompatibility in crucifers is correlated with glycoproteins localized in the cell wall of the stigmatic papillae that are encoded by the S locus glycoprotein (SLG) gene. When fused to the [beta]-glucuronidase (GUS) reporter gene, the 5[prime] upstream regulatory region of SLG directed high level expression in the papillae of transgenic Brassica plants. Hi...

During the early stages of microsporocyte ontogeny in Helleborus foetidus L. there is protoplasmic continuity between the cells of the tapetum and between the individual sporogenous cells, but not between the two tissues. The plasma canals and plasmodesmata are progressively sealed off by the deposition of thick callose walls, so that by the first meiotic division, each pollen mother cell is is...

NGIOSPERM gametogenesis, particularly on the male side, is highly susA ceptible to disturbance by either environment o r genotype. Exemplary of environmental agents, sodium a,P-dichloroisobutyrate disrupts pollen development, the effect being sufficiently specific and complete to warrant use of this chemical for purposes of emasculation (EATON 1957). Instances of genetic control are commonplace...

B chromosomes (B's), knobbed chromosomes, and chromosome 6 (NOR) of maize undergo nondisjunction and micronucleus formation in binucleate tapetal cells. These chromosome instabilities are regular events in the program of tapetal cell death, but the B's strongly increase A chromosome instability. We studied 1B and 0B plants belonging to selected lines for high or low B transmission rate and thei...

A polarized division occurs normally in the development of microspores in plants. The result is a presumptive vegetative cell and generative cell within the young pollen grain. The generative nucleus in Tradescantia synthesizes DNA and considerably later, in the pollen tube, it divides to form two sperm nuclei. The vegetative nucleus probably degenerates in the pollen tube. In Tradescantia, it ...

After meiosis, an unequal cell division generates the male gamete lineage in flowering plants. The generative cell will undergo a second division, giving rise to the two gametes, i.e. the sperm cells. The other cell will develop into the vegetative cell that plays a crucial role in pollen tube formation and sperm delivery. Recently, the vegetative cell has been suggested to be important for pro...

H E haploid cycle of plants offers some distinct advantages to genetic T analysis. Here inheritance is not complicated by dominance relationships, and segregations are much less involved than in disomic inheritance. The greatly simplified problem of rearing large populations and the opportunities in some instances of tetrad analysis are other of the many well known reasons why new inherited cha...

Male sterility in plants has been strongly linked to mitochondrial dysfunction. Chemical hybridization agent (CHA)-induced male sterility is an important tool in crop heterosis. Therefore, it is important to better understand the relationship between mitochondria and CHA-induced male sterility in wheat. This study reports on the impairment of mitochondrial function duo to CHA-SQ-1, which occurs...