Page 7 - Ninja Plants: Survival and Adaptation in the Plant World
P. 7

Another unusual feature of the Rafflesia is that it has no leaves or
                   stems. It grows low to the ground, attaching itself to and burrowing
                   inside the tropical grapevine Tetrastigma. The only part of the Rafflesia
                   that is visible outside of the host vine is its giant five-petaled flower.
                   Why does the Rafflesia attach itself to the vine in the first place?
                   Without green leaves, the Rafflesia cannot produce its own food
                   through photosynthesis. Instead, it must live as a parasite on the host
                   grapevine. Then the Rafflesia obtains all its nutrients from the vine it
                   grows on.
                       The dead horse arum (Helicodiceros muscivorus), native to the stony
                   islands of Corsica and Sardinia in the Mediterranean Sea, also smells
                   like rotting flesh. And yes, the smell is the plant’s way of attracting
                   flies—in this case blowflies—for pollination. This plant can do
                   something else extraordinary: it can raise its body temperature. That’s
                   right, this plant has a built-in heating system! The ability to grow
                   warm (thermogenesis) is rare among plants, but it is part of respiration.
                   The dead horse arum’s warmth, along with its stench, attracts flies to
                   its flower.
                       Blowflies are critical to the plant’s fertilization, which isn’t as simple
                   as you might think. Each dead horse arum flower has only a two-day
                   window of opportunity for pollination. The female part of each flower
                   can receive pollen for only one day, but on that day, the male part
                   is not mature enough to release pollen. On the following day, when
                   the male part can release pollen, the female part has already withered.
                   That’s where the blowflies come in. The dead horse arum emits its
                   characteristic horrid odor to attract blowflies for pollination at just the
                   right time. On day one, the flies explore the plant’s flower, looking for
                   a place to lay their eggs. When they reach the female portions of the
                   flower, spines in the floral chamber trap the insects inside, holding them
                   overnight. During this time, the flies release pollen picked up from
                   earlier visits to other flowers. The next day, the spines wilt and the flies
                   are able to exit the chamber. As they leave, they pass by the male part of
                   the flower, which on this day is ready to release pollen. The blowflies
                   get covered in more pollen and fly off to pollinate more female flowers.
                   The one-day delay is perfect timing for the dead horse arum.



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