The influence of pretreatment on cell stage progression and the time of DNA synthesis in barley (Hordeum vulgare L.) uninucleate microspores

Abstract

The objective of this study was to correlate the time that DNA synthesis first occurs in haploid microspores of barley with cell cycle and plant morphological stages and to subsequently assess the influence of pretreatments on DNA synthesis at different stages of microspore development. Spikes with microspores in early, mid, and late uninucleate stages of the two-rowed barley cultivars Manley and Igri were subjected to two commonly used pretreatments. First, during cold pretreatment for 28 days there was a slow increase in relative DNA values as well as asymmetric nuclear divisions in some microspores. Second, during a 4-day cold plus 0.3 M mannitol pretreatment, there was very little change in the microspore stage or DNA values indicating that for the duration of this pretreatment the progression of the cell cycle was essentially suspended at all stages, both in Igri and Manley. The results are discussed relative to the potential for genetic transformation of microspores.

The effect of cold and heat treatments on the anther culture response of diverse rye genotypes

“…Shim and Kasha (2003) discovered that after 3 weeks at low temperature, over 70% of barley microspores originally collected at the mid-uninucleate stage were still uninucleate but that most of them started DNA synthesis (the first mitosis) after 4 weeks in the cold. Cold pre-treatment seemed to delay the microspore development, subsequently contributing to a better androgenesis.…”

In vitro haploid and dihaploid production via unfertilized ovule culture

“…DH systems are widely applied in breeding (Thomas et al 2003), genetic mapping (Forster and Thomas 2005), and mutation studies. Meanwhile, they can provide useful systems for transformation and fixing transformation events Haploid plantlets Lakshmi et al 2002 Saffron ( (Shim and Kasha 2003). DHs have many advantages for application in basic genetic research, molecular studies, and practical applications in plant breeding.…”

Microspore development during in vitro androgenesis in triticale

“…Numerous studies have been published on the changes suffered by microspores when stimulated to undergo ⎯⎯⎯⎯ sporophytic development (see Smýkal 2000, Shim andKasha 2003). Nevertheless, no quantitative analysis of the development of microspores over time has been undertaken.…”