Changes of pollen viability after preservation of Paeonia lactiflora in different provenances.

Pollen contains all the haploid genetic information of species and is of great significance to preserve germplasm resources safely and effectively. The acquisition of high quality materials is a very important step in germplasm preservation. This study compared the viability and physiological condition of Paeonia lactiflora pollen from several provenances after preservation, to explore the effect of provenance difference on pollen viability and physiological responses after preservation. The results showed that: the pollen viability of two cultivars were significantly different in provenances after preserved at -20 °C or liquid nitrogen (LN) for 3 months, the pollen viability of 'Fen Yu Nu' showed Lanzhou > Beijing > Luoyang > Heze, while the pollen viability of 'Zi Feng Chao Yang' showed Luoyang > Beijing > Heze. Similarly, the oxidative stress levels of the Paeonia lactiflora pollen after preservation with LN or -20 °C were also significantly different among the provenances, and there was a relationship between the viability and the oxidative stress levels produced by the provenances differences. Reactive oxygen species (ROS) content, malondialdehyde (MDA) content, superoxide dismutase (SOD) activity and glutamate reductase (GR) activity in pollen from different provenances were contrary to the changes of viability; while catalase (CAT), ascorbic acid peroxidase (APX), ascorbic acid (AsA) and glutathione (GSH) were consistent with the changes of viability. The results indicated that the responses of antioxidant systems of two cultivars pollen to preservation with LN or -20 °C were different in provenances, and this difference was one of the reasons for the different viability of pollen after preservation with LN or -20 °C.