Saturday, February 9, 2013

In Congo, parrots are flowers

Species name: Impatiens niamniamensis

Common name: parrot plant, congo cockatoo

Location: UWO Greenhouse

The parrot plant, as its other common name may suggest, is native to Central Africa in the very small remains of what used to be a vast tropical rainforest. There haven't been any biodiversity studies recently that examine this species, but due to the rate of deforestation and the spreading drought in the area, I can imagine this species is probably at risk in its native range. Fortunately, this plant is readily propagated in the greenhouse so if rehabilitation studies were ever performed there is a genetic bank from which to select plants to recolonize the area. Due to its seed dispersal mechanism it may become invasive in some areas.

Like in the touch-me-nots (which are in the same genus; you can read all about them HERE), the seed pods of this species are like little seed grenades. When mature, even the lightest touch will cause the seed pods to explode and seeds go flying in all directions. An excellent dispersal mechanism, especially because these plants thrive in tropical climates. Here, the soil very quickly loses its organic nutrients in the top layers of soil and so plants need to disperse great distances from the mother plant in order to be able to successfully root and grow in the soil. Most greenhouses that propagate and sell the parrot plant don't even bother collecting the seeds, since the plant is so easily propagated from cuttings. When you do a cutting of a plant, usually you need to dip the exposed cut into a rooting compound which is full of plant hormones that signal the maturation of root cells from the plant's stem cells (in plants we call these meristematic cells). The plants are then placed in a soil substitute that is very porous, allowing for easy extraction of the plant from the medium to be planted in soil once the roots start to develop. This plant is even easier than that: cut a small piece off the end of a stem, put it in a cup of water and wait a few days. Sometimes it also helps to place a clear plastic bag upside down over the plant; this causes the environment around the plant to be very humid and warm, but air can very easily enter and exit through the bottom of the bag. After a few days, you'll start to see small roots form at the bottom of the stem. Put the stem in some soil, and there you go. A new plant! This is the way that one of my former students gave me my parrot plant about 4 years ago. I still have it, and while sometimes it just looks like a stick in the ground, it produces a new flush of flowers a couple of times a year. I have yet to see one of the fruit grenades produced, though.

The flowers of this plant are very well protected from predation, while at the same time attracting all different kinds of pollinators. Butterflies, bees and hummingbirds will be attracted to the flowers which produce a huge amount of nectar, as well as insects that have the ability to chew through the walls of the flower; since it's difficult for them to reach the bottom of the flower via the opening, they just bite through the outside and get their nectar reward by cheating. The protection of the flowers doesn't actually come from the flowers themselves, but from the stem of the plant while the flowers are developing. The plant produces large amounts of oxalic acid that are stored in crystals on specialized hairs on the stem right above the developing flowers. If a herbivore tries to come along and chew off one of the flowers, they will be instead rewarded with a mouthful of calcium oxalate crystals that will completely destroy their digestive system. Cats and dogs seem to have some sort of ability to sense this toxin produced by plants; I've never heard of a cat trying to eat through rhubarb leaves which have the same oxalic acid. Small children aren't so smart! It won't greatly harm a small child, but it will destroy your sense of taste for a good couple of days, as well as potentially making your mouth bleed quite a bit so parents of small children beware. The flowers of this plant can be interpreted as candy by small children so this plant shouldn't be within arms' reach.

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