As seen from a botanist's point of view.

Yes, it's charming and thought-provoking and amazing. But for those of us in the green world, the really striking thing about the animated film Wall-E is that a plant is the object of desire, the grail, the Ark of the Covenant. This happens so rarely in movies. (One exception is an obscure but admirable satire, released a couple of years ago, called Idiocracy, in which the hero teaches really dumb people on an apocalyptic future Earth that plants need to be properly tended so that people will have food to eat and air to breathe.)

The precious little green thing on which the Wall-E plot turns consists of just a few leaves clasping a viney stem.

To get a botanist's perspective on the plant as plot-driver, I took Gerry Moore, director of the Department of Science at the Brooklyn Botanic Garden, to the movie. Moore, who monitors the rise and fall of plants within a 50-mile radius of New York City, was looking quite collegiate in shorts and a Phillies baseball cap that belied his weighty résumé. He was modest and flexible enough to say, "I hate to impose scientific rigor on a movie."

Maybe the exercise he got pushed into (I paid for his ticket) is a bit on the literal side, but it is interesting to see where he found the movie departing from credibility.

The movie's setup: Apparently nothing is left on Earth but ruins, piles of trash, and Wall-E, a solar-powered, trash-compacting robot. It seems that the only living thing around is a single cockroach. Earth's human population has fled to a gigantic space colony. A scout from the space ship, the feminine and graceful robot Eve, meets Wall-E and returns to the ship with a plant he's discovered. The small green plant registers with some back at the colony as a foreign contaminant, dangerous to the status quo, but with others—including the good-guy captain—as a sign that life on Earth might be possible again.

The biggest problem for Moore is that only one plant was found. "It's a stretch to believe that the Earth could be restored to life-sustaining status because of the presence of a single live plant," he said over dinner after the movie.

Behind the closing credits, we saw plant life unfurling quickly on Earth—sunflowers, fruitful vines, trees.

"They're down to one plant—a seedling of some kind of vine," observed Moore. "There's no way a single individual plant could give rise to wheat, grapes, and re-vegetate the earth. Not in human time, anyway. In evolutionary time, of course, that's what really happened."

Still, Moore was thrilled to have green things seen as important. "The story line puts plants front and center. It wasn't the roach they were looking for."

One of the merits of the movie is that it avoids being obviously didactic; no one ever uses the word photosynthesis. But, implicitly, the movie stresses the life-giving talent plants have—that is, to make an organic product from strictly inorganic ingredients.