Pollen hydration status at dispersal: cytophysiological features and strategies

The aim of this paper is to draw attention to partially hydrated pollen, namely, pollen grains having a high water content (> 30%); this type of pollen is more frequent than previously thought. Various cyto-physiological strategies are used to retain water during exposure and dispersal such as cytoplasm carbohydrates; in the absence of such strategies, fast pollination must be ensured, because uncontrolled loss of water leads to pollen death. On the other hand, a state of partial hydration allows a fast tube emission (even within 3-5 min). Several methods for determining the hydration status of pollen at anthesis are proposed.