Dynamics of ROS production, SOD, POD and CAT activity during stigma maturation and pollination in Nicotiana tabacum and Lilium longiflorum.

Reactive oxygen species (ROS) are a key regulator of physiological processes in pollen grains, and an essential component of stigma exudate. The mechanisms of this redox-based regulatory system and its features in different plant groups are still unclear. For two species from different families (tobacco and lily), the dynamics of total ROS, O generation, and HO concentration in stigma exudate were examined using EPR spectroscopy and quantitative colorimetric analysis.

The Balance between Different ROS on Tobacco Stigma during Flowering and Its Role in Pollen Germination.

The concept of ROS as an important factor controlling pollen germination and tube growth has become generally accepted in the last decade. However, the relationship between various ROS and their significance for the success of in vivo germination and fertilization remained unexplored. For the present study, we collected stigma exudate on different stages of stigma maturity before and after pollination.

Pollen Germination and Pollen Tube Growth in Gymnosperms.

Pollen germination and pollen tube growth are common to all seed plants, but these processes first developed in gymnosperms and still serve for their successful sexual reproduction. The main body of data on the reproductive physiology, however, was obtained on flowering plants, and one should be careful to extrapolate the discovered patterns to gymnosperms. In recent years, physiological studies of coniferous pollen have been increasing, and both the features of this group and the similarities with flowering plants have already been identified.