Effects of copper deficiency on pollen fertility and nucleic acids in the durum wheat anther

Abstract

The effects of continuous copper deficiency and of temporary deficiencies initiated prior to (initial deficiency) or after (terminal deficiency) the end of tillering (a stage preceding the meiotic cycle) on pollen formation were investigated in durum wheat grown on a nutrient solution. The effects of the treatments on pollen viability (FCR test) and on the proline content of the pollen grains suggested that copper deficiency induced a nearly complete sterility of the pollen formed and inhibited all grain production. Temporary copper deficiencies significantly reduced the viability rate and the number of proline-rich pollen grains without affecting pollengrain production. Cytophotometric measurements showed that initial copper deficiency induced a significant increase in the proportion of polyploid microspore mother cells (MMCs), whereas terminal copper deficiency blocked endomitotic DNA syntheses. Protein metabolism was markedly altered by the treatments. The RNA content of the cytoplasm of tapetum cells was decreased by 34%–48%, depending on the treatment. The autoradiographic study showed that the stress caused by copper deficiency enhanced [3H]uridine incorporation into microspore cytoplasm RNA and also into the tapetum cells in the case of temporary deficiencies. The incidence of the treatments on the ploidy of the mother cells and on the disturbance of protein metabolism, particularly in tapetum cells, is discussed.