字幕列表 影片播放 列印英文字幕 Hi guys! As something of a belated Halloween episode, today I'm going to be talking about a couple of really cool parasitic plants. When talking about parasitic plants, there are a couple of terms that come in handy when describing these plants. The first pair of these is facultative and obligate. A facultative parasitic plant can complete its life cycle without its host, though it would prefer to have its host. An obligate parasite has to have its host to complete its life cycle. A second pair of terms is holoparasite and hemiparasite. Now a holoparasite has to no chlorphyll, meaning its completely reliant on its host for nutrients. A hemiparasite, however, might have some chlorophyll, so it can produce some of its own nutrients, but still needs its host. So the first of the parasitic plants I'm going to talk about is a holoparaiste, and that's the Albino Redwood, Sequoia sempervirens. Now most redwoods are large, normal trees that have chlorophyll to produce their own nutrients. And albino redwood is a mutant that doesn't contain chlorophyll, which is why its leaves look like this. And it because it doesn't contain chlorophyll it can't create its own nutrients. As a solution, albino redwoods graft their root systems onto the root systems of healthy redwoods so that they can gain nutrients that way. There are only a handful of these albino redwoods known to exist, and their locations are kept secret to keep them safe. Now a parasitic plant you might not normally think of is mistletoe. Mistletoe describes a lot of plants, but one specific example is Viscum album, European Mistletoe. Mistletoe grows on the trunks of trees and absorbs its nutrients by leeching them from the tree. They would also be a hemiparasite, because they do contain some chlorophyll to produce their own nutrients. Mistletoe is actually poisonous because it contains viscumin, a compound that inhibits protein synthesis in cells. Now this last parasitic plant is a weird one. Its common name is Sandfood, but its scientific name is Pholisma sonorae. Sandfood is a very rare flowering plant that grows in the deserts of the western US. Only the plant's inflorescence, or flower, is visible above the sand level, and its stems grows underground. This stem can be up to 6 feet, or 2 meters, long and it reaches down through the ground to graft onto the root systems of neighboring shrubs. This plant also does not have chlorophyll, as you can tell from this picture, it is not green at all. This means it is also a holoparasite like the Albino Redwood. Thank you for watching this quick video about parasitic plants. For more botanical content, check out www.brilliantbotany.com. Don't forget to like and subscribe, thank you so much for watching, and I will see you next time.
B2 中高級 寄生植物的奇怪世界 (The Weird World of Parasitic Plants) 699 43 稲葉白兎 發佈於 2021 年 01 月 14 日 更多分享 分享 收藏 回報 影片單字