Methods are provided for imparting desirable phenotypic traits to transgenic plants, among them being increased tolerance to external stresses such as drought, freezing temperatures, high salt conditions, and the like. In addition, the present invention is directed toward methods for increasing the yield of seeds from plants by using the pollen from a transgenic plant transformed to overexpress a vacuolar proton-pumping pyrophosphatase to fertilize plants, and to the pollen of transgenic plants itself.
