The Plant (also known as the Plant in the Boot) is a plant in the movie WALL•E.
It is a small seedling tree that was growing in a broken fridge on Earth since the toxin levels have risen down. It was discovered by WALL•E, a little robot programmed to clean up and compact Earth's trash. However, he has developed a curious personality which made him split the fridges door in two with his head-mounted laser. Despite being just a plant, it plays a serious and critical role in the film.
When WALL•E sees the plant, he digs it up and puts it in an old boot he had found earlier. WALL•E takes the plant to the WALL•E transport vehicle where he lives and where he takes all the interesting items he finds.
Later in the film, WALL•E shows the plant to his new friend EVE. Her programming identifies the plant and causes her to take the plant and store in a protected space inside her body. She then goes into a stand-by state, showing only a glowing green leaf symbol and waits for her spacecraft to return. Concerned, WALL•E takes her on dates and tries to revive her, but all his attempts fail and he becomes discouraged as he thinks that he might have lost the one he loves. The ship returns whilst WALL•E is away crushing garbage and he races back for EVE. A robotic arm loads her onto the ship and WALL•E manages to climb onto the side ship before it takes off, but orders Hal, his pet cockroach, to stay on Earth. There are four other EVE units onboard the probe ship but WALL•E can identify the EVE he knows and loves by the glowing green leaf symbol on her chest.
After an indeterminate amount of time in space, the probe ship arrives at a much larger spacecraft a BNL starliner called the Axiom. Onboard the Axiom, the probe ship unloads the EVE units and the naive WALL•E unit falls off the ship once gravity is re-engaged in the Axiom's docking area. He manages to reach the EVEs shortly before a tiny robot called GO-4 notices that one of the EVEs had found a plant and summons a cart-like transport robot called MVR•A to take the EVE away. GO-4 hops on the transport bot and a robotic armload EVE onto it. WALL•E immediately goes after the MVR•A and eventually reaches it.
MVR•A takes GO-4, EVE and WALL•E to a room where they meet an organizing bot called TYP-E. TYP-E allows them to enter an elevator that takes them to the bridge of the Axiom. There they meet the ship's steering wheel and autopilot called AUTO. AUTO secretly informs GO-4 about the strategy and opens a hole in the floor that he uses to reach the captain who is in the lower room. WALL•E falls to the lower room because he was standing on the hole. AUTO awakens the captain and the captain's hoverchair takes him to the bridge. He also accidentally pushes a bewildered WALL•E to the bridge with him.
On the bridge, AUTO awakens EVE in order for the captain to witness the plant specimen and then plot a course back to Earth. But after the captain "orders" the ship's computer to open EVE's chest cavity, they see nothing inside. The captain is a bit nonplussed and asks AUTO if they missed something, but AUTO says that EVE's memory is faulty and she had not found a plant at all. EVE alarmed, falsely accused WALL-E of stealing the plant, but WALL-E showed he didn't know it disappeared. Unbeknownst to them, GO-4 had stolen it from EVE under AUTO's orders to make it look like EVE was defective.
EVE and WALL•E are taken to the ship's Repair Ward where EVE is examined for repairs and WALL•E is waiting to be cleaned. WALL•E thought it appeared EVE was being hurt and rushes in to save her, but accidentally causes releases the rejects, who declare him a hero. Alas, a group of patrolling Stewards mistakenly identify them as rogue robots. Frustrated with WALL-E's interference, EVE decides to put him into a space pod and send him back to Earth, but he wouldn't leave without her. EVE and WALL•E are interrupted by GO-4 who enters the room. EVE and WALL•E hide and see GO-4 placing the plant in the space pod. EVE finally realized that WALL-E didn't steal or lost the plant from her.
GO-4 tries to dispose of the plant by blowing it up with the pod, but WALL•E enters the pod and takes the plant. But before he manages to inform EVE, GO-4 launches it into space and activates its self-destruct sequence. EVE uses a service airlock to go after WALL-E's pod and GO-4 leaves the room. WALL•E manages to escape the pod using a fire extinguisher before the pod explodes and saves himself and the plant he earlier put inside. He catches up with EVE and shows her the plant and she takes the plant back into her chest with her tractor beam. After a brief embrace, they fly around the Axiom observed by some passengers and return aboard and accidentally lock a welder robot outside the starliner.
EVE manages to reach the captain's deck and gives the plant to him. Captain McCrea is eager to return to Earth and summons AUTO to see the plant, but AUTO insists the captain give the plant to him and it is revealed that AUTO has a classified, 700-year-old Directive A-113 by BnL CEO Shelby Forthright that autopilots should not allow starliners to return to Earth because life was no longer sustainable on the planet. McCrea points out that life is now clearly sustainable and the existence of the plant proves it, if one plant can survive on Earth, then that certainly proves that Earth is habitable.
AUTO is unable to disobey his directive, which he doesn't allow the captain to take the Axiom back to Earth and summons GO-4 to take the plant and throw it into the garbage chute. EVE tries to take the plant back from GO-4, but he tosses it into the chute. However, the plant is saved twice since it landed on top of WALL•E as he was climbing up the chute to reach EVE. When WALL•E appears from the chute, GO-4 traps EVE to prevent her from reaching WALL-E and AUTO attempted to take the plant from him. WALL•E knowing it was needed for EVE's directive refuses to hand it over and quickly shoves the plant into his compacting chest, but AUTO suddenly shocks him with his taser, causing his systems to become drained. WALL•E and the plant fall down the chute as AUTO deactivates EVE using her red boot and drops her down the chute as well. He then locks the horrified McCrea into his quarters.
In the garbage airlock, EVE and WALL-E are compacted by the WALL-As into large piles of trash cubes intending to be ejected to space. EVE frees herself from the trash and pulls a weakened WALL-E and the plant free as the trash is shot into space. At the same time, M-O having followed WALL-E's filthy treads, holds the indoor doors open enough for the two desperate robots to reach to him. As EVE examines and tries to repair WALL-E, he hands her the plant still safe inside his chest and tells her to take it the the lido-deck and finish her directive. Even though she changes her directive from delivering the plant to caring for him, she agrees to fulfill her directive in order to get him back to Earth so that he could be repaired.
The two, along with M-O head out of the airlock and are joined by the reject bots to heading for the lido-deck. But AUTO becomes determined to prevent them from reaching them as he and the captain fight for control of the ship.
Eventually, EVE and WALL•E manage to reach the lido-deck and get the plant to the Axiom's holo-detector with the help of M-O passing the same plant to some humans and other robots and the captain shuts AUTO down, but WALL-E is badly damaged. The Axiom returns to Earth and McCrea along with the other humans plant the plant into the soil. EVE repairs WALL-E and restores his memory, before the two reunite. During the credits of the movie, EVE and WALL•E are observing a large tree and it is revealed that the tree is the same plant that WALL•E had found in the fridge.