increase in pollen aperture number, suggesting that pollen apertures are under strong selection pressure. This trend can be observed by comparing the aperture patterns in basal angiosperms (including monocots) with those of eudicots. Different developmental strate-gies operate for pollen apertures in basal angiosperms
Reuse your fountain pen by refilling the ink. Use the method that is suitable for your type of pen. 1  Fill ink in a piston converter pen by removing the cap and barrel and then dipping the nib inside the ink bottle. 2  Lower the piston to remove the air inside. 3  When you pull up the piston, the ink will be sucked in.
Most pens use either a piston filler or a cartridge; many pens can use a converter, a device which has the same fitting as the pen's cartridge and has a filling mechanism and a reservoir attached to it.This enables a pen to either fill from cartridges, or from a bottle of ink.hat some form of pen with an ink reservoir was available in Europe in the 17th century is shown by contemporary references. In Deliciae Physico-Mathematicae (a 1636 magazine), German inventor Daniel Schwenter described a pen made from two quills. One quill served as a reservoir for ink inside the other quill.