plant is a noun but alkaline-loving is not a noun.

plant is not an adjective while alkaline-loving is an adjective.

plant is a verb but alkaline-loving is not a verb.

plant (noun)	alkaline-loving (noun)
buildings for carrying on industrial labor
(botany) a living organism lacking the power of locomotion
an actor situated in the audience whose acting is rehearsed but seems spontaneous to the audience
something planted secretly for discovery by another

plant (adjective)	alkaline-loving (adjective)
	thriving in a relatively alkaline environment; (especially of plants requiring a pH above 7)

plant (verb)	alkaline-loving (verb)
put or set (seeds, seedlings, or plants) into the ground
fix or set securely or deeply
set up or lay the groundwork for
place into a river
place something or someone in a certain position in order to secretly observe or deceive
put firmly in the mind