In: Phyton 54, Fasc. 2 (2014): S. 321-332 with 4 figures DOI: 10.12905/0380.phyton54(2)2014-0321

Key words: Nicotiana tabacum L., tobacco, embryogenesis, microspore culture, anther pretreatment, oxidative stress, thiols, proline, malondialdehyde, peroxidase activity.

Summary

Stabentheiner E., Oberländer A. & Willfurth R. 2014. Microspore reprogramming in tobacco – effect of cold pretreatment on anther stress markers and embryogenic efficiency. – Phyton (Horn, Austria) 54 (2): 321–332, with 4 figures.

Embryogenesis or androgenesis is the result of a developmental shift of male microspores from the gametophytic to the embryogenic pathway. Cold exposure is often used as the mandatory stress treatment triggering this developmental shift. Young flower buds of tobaccao (Nicotiana tabacum L.) were exposed to cold pretreatment (4 °C) for up to 4 weeks and the formation of embryo like structures and the content of stress markers (proline, malondialdehyde, total and oxidized thiols, total antioxidative capacity, and peroxidase activity) were investigated. Exposure of buds for more than two weeks drastically reduced embryogenic efficiency, whereas 5–14 days of cold pretreatment had a positive effect. The changes observed in the developing anthers are rather connected with anther maturation than with oxidative stress. The cold pretreatment did also not indicate excess oxidative stress during the first two weeks. After two weeks, however, a steep drop in total thiols and proline and a dramatic increase in the percentage rate of oxidized thiols could be observed and were accompanied by a drastic decrease in the embryogenic efficiency. The results support the thesis that an appropriate cold treatment provides the necessary conditions for reprogramming of microspores, whereas a longer pretreatment results in excessive stress and cell death.