. . . plants are not sentient beings . . .
Many years ago a Canadian Broadcasting Corp documentary addressed the issue of whether 'plants' can show emotion, or even communicate.
One of the studies they cited involved trees that can generate changes in their biochemistry to repel parasites and fight disease. The scientists introduced a parasite at one edge of the forested area they were observing and found that trees on the other side began initiating their defences before the parasites arrived in their area.
Does the ability to recognize threats, mobilize reactions, and warn your fellow-entities (an act of service?) speak to the question of souls, consciousness, sentience and related issues?
I think it depends upon how you, individually, define those words and concepts. Personally, I like the philosophy that the Cosmos is a single living entity; we are just individual parts of that entity, like single cells in the greater body. Some of the definitions of concepts like soul and consciousness are human-created attempts to persuade ourselves of our self-assumed superiority, like the cells in the left thumb trying to prove they are better than the cells in the right kneecap.