Tube, a pale yellow colour (5)
I believe the answer is:
This clue is a double definition.
'tube' is the first definition.
(I know that straw is a type of tube)
'a pale yellow colour' is the second definition.
(I've seen this before)
(Other definitions for straw that I've seen before include "Pale yellow colour" , "Pale-yellow - through which one can drink" , "Stalk of dry grass" , "Dried stalks for fodder" , "remnant of harvest" .)