Albino redwoods trade taking food for trapping toxins
An albino’s life in the wild isn’t easy. Without natural camouflage for non-snowy environments, animals are more easily spotted by predators and potential prey, leaving them in danger of being eaten and possibly going hungry. Severe sunburn is also a big concern, as the melanin that colors skin also helps protect against ultraviolet radiation. These problems are still workable for some animals, but when albinism turns up in a photosynthesizing plant, survival becomes a bit more of a mystery. Since plants need the pigment chlorophyll to feed themselves, only recently have scientists been able to put together a possible explanation for ‘ghost’ albino redwood trees.
Like albino animals, a mutation in the albino redwood trees (Sequoia sempervirens) has stripped them of the ability to grow pigment. In this case though, not growing chlorophyll not only leaves the plants white, but also without a way to make their own food. The only reason they survive at all is that they grow as sprouts connected to an adult tree, which allows them to basically siphon off resources like a parasite. They don’t grow very large, as the parent tree will eventually cut off the supply of free food. However, that ‘eventually’ can be as long as 100 years, which is a long enough time, even for a tree that can live 2,000 years, that scientists wondered if the albino sprouts were actually more than just dead weight on the adult tree.
Scientists started investigating the DNA and structure of both completely white albino redwoods, as well as “chimera” variations that can grow needles that are half-white, half-green on the same branch. Rather than just confirming that the white portions of the branch were stealing sugar from the greener bits, they also found that the white tissue was sponging up toxins like cadmium, copper and nickel. Green portions of the needs had these heavy metals as nearly dangerous thresholds, but the white portions were holding on to double those amounts.
This realization suggests that the albino offshoots may be helping out their parent tree as a sort of sacrificial poison sponge. The white needles can move water from roots faster than sugar-producing, green needles, which lets them grab and trap metals before they can make their way into the larger tree. Like a built in remediation team, the seemingly dangerous mutation of albinism may be a bit of a safety net for redwoods, which helps explain why the gene variation keeps popping up in organisms that should otherwise just die for how unfit they’d normally be.
Botanists normally try to keep the locations of few albino redwoods we know of a secret so they’re not over-visited or poached. If this hypothesis about how albinos help adult trees proves true, they may be even more important to preserve so as to not interrupt their assistance to the parent tree. It might also mean people might get to see more of the so-called “ghost trees” though, since grafting albinos onto trees in polluted areas may be an effective way to help restore areas littered with fertilizers, mine tailings or other waste.
Source: The Mystery of California's 'Albino' Redwoods Could Be Solved by Sarah Keartes, Earth Touch News Network