Trees naturally absorbed CO2 through photosynthesis (光合作用), releasing oxygen, storing carbon for decades, or even centuries. Biotechnology firm Living Carbon says lab trials of its genetically-changed poplar trees take up more carbon and grow 1.5 times faster than unchanged ones. The team added genes from pumpkin to the poplars, which makes their photosynthesis more efficient, turning more carbon dioxide into sugars to create wood biomass (生物量).
Though the firm's lab results are promising, biologists warn that high growth rates are not guaranteed in the wild as the poplars compete for sunlight with other plants and trees. Genetically-modified (GM) supertrees may also need much watering and fertilizer to keep their rapid growth.
The results are important given the rate of climate change and climbing CO2 levels in the atmosphere. But critics say there are risks to planting GM trees in the wild if they reproduce with other trees, or negatively affect other plant and animal species. Living Carbon says trees are a hybrid that can only reproduce from cuttings, so cannot cross-pollinate (授粉) with wild trees.
If the field trials are successful then it will still take time to get approval from the government. One sixth, around 135, tree species in the US may face extinction due to climate change, foreign insect species, or disease. And even though field trials of a GM chestnut tree have shown its ability to resist some foreign disease that wiped out billions ofAmerican chestnuts, it still has not been approved for planting.
If CO2 storage is the aim then there are species that already fit the bill. California's Redwood trees store more carbon than any other species. Redwoods are not suitable for every forestry plot, so creating climate adaptable trees through reproducing programs that fit into local ecosystems is the goal. But in the rush to fix the climate crisis, increase CO2 uptake, and carbon storage, GM supertrees may be part of that solution.
