Ultrastructure of S3S4 genotype pollen grains of Oenothera organensis

The exine of the S3S4 genotype pollen grains of O. organensis is furnished with beaded viscin threads as an efficient device for their transport by pollinating agents. The sexine structure is expedient for absorption of water and stigmatic exudate. The vegetative cell cytoplasm has the pertinent organelle system for the synthesis of starch, lipids, proteins and polysaccharides. The generative cell is, however, dormant but has a normal complement of subcellular bodies capable to resume their activity efficaciously after pollen hydration and activation; and does not transmit paternal plastome to the zygote.