To keep their (concentrated, moist) sugars from oxidizing, and effectively becoming caramel-like or tar-like, and hence less appetizing to the animals that are going to be tricked into distributing the seeds. Or rather, appetizing for too short a time.
Multinationals put anti-oxidants into junk food to promote shelf-life. Nature puts anti-oxidants into fruit to promote branch-life.
Warning! I might just be making this up. Check more authoritative sources if this info matters to you.
Edit: It occurs to me that the essential oils (fragrances) are also subject to being oxidized into something less savory than the original. Maybe more at risk of oxidizing than the sugars.
To keep their (concentrated, moist) sugars from oxidizing, and effectively becoming caramel-like or tar-like, and hence less appetizing to the animals that are going to be tricked into distributing the seeds. Or rather, appetizing for too short a time.
Multinationals put anti-oxidants into junk food to promote shelf-life. Nature puts anti-oxidants into fruit to promote branch-life.
Warning! I might just be making this up. Check more authoritative sources if this info matters to you.
Edit: It occurs to me that the essential oils (fragrances) are also subject to being oxidized into something less savory than the original. Maybe more at risk of oxidizing than the sugars.