The status of a purchase order request needed to fulfill an order can be viewed directly from the sales order.
Once a purchase order is requested from an order, the quantity field will display a purchase order icon (book). This is the same icon as the Request Purchase Order button.
The purchase order request status can be discerned through the color of the purchase order status icon:
NOTE: Purchase order numbers for accepted and ordered items can be viewed by hovering the cursor over the purchase order icon.