仙人掌vs Succulents
在干燥和热环境中生长的植物面临的主要问题是由于蒸腾而导致的水分流失过多。仙人掌和其他多肉植物来克服这个问题的重要适应是它们的碎屑代谢(CAM)。凸轮植物在晚上打开气孔,捕获二氧化碳,并在热干燥的白天关闭。这会更大程度地减少植物中的蒸腾作用。
仙人掌
仙人掌属于仙人掌科。它们的形态与其他正常植物不同。这是在干燥和热环境中节约水的一种改编。在仙人掌中,将叶子修饰成形成刺,并修饰茎以进行光合作用。仙人掌有不同类型。最高的仙人掌是Pachycereus Pringlei。它高约19米。最小的仙人掌是Blossfeldia Liliputiana。仙人掌的大花来自称为areoles的特殊结构。仙人掌是多汁的植物。 In most cacti leaves are modified into spines. The spines can absorb moisture in the air to some extent. It hardly loses the absorbed water. The spines perform another important function. They trap moisture and create a moisture layer near the surface of the cactus stem. This helps the plant to reduce transpiration and thus conserve some water. Spines can also protect the plant from herbivores. The spines develop from areoles. Areoles are identical to the nodes on the plants. Only few cacti possess leaves, and those are also very small and they fall off soon to reduce transpiration. Some ancestral cacti have large leaves, and they do not have succulent stems. In addition to the photosynthesis cacti stems also store water. The stems are usually enlarged to store water. Most of the time cacti have a waxy layer on the stems, and that is present to reduce transpiration of water and conserve water. As the plant contains a lot of water, the parts of the plant that gets separated from the plant can survive for a longer period. Then they can root when the rainy season comes. When considering the body shape of the cactus plant it is cylindrical. This shape reduces the surface area which receives sunlight. Cacti roots are not deeply rooted. They are close to the surface and are wide spread to collect maximum possible amount of water covering a larger area. This is a good adaptation to the rains, which are not frequent in those areas.
多肉植物
多元是一种适合炎热和干燥环境的植物。他们有能力将水保留在植物内。多肉植物能够将水储存在其茎,叶甚至根部。由于根茎,Corms,鳞茎和块茎根源而在不利条件下生存的植物可以在多肉植物下分类。多肉植物的肉质外观是由于水的储存。这被称为多肉。在大多数多肉植物中,叶子不存在或减少。即使厌恶它们是很小的叶子,可以减少蒸腾作用。同样,它们通过减少气孔数量来减少蒸腾作用。在多肉植物中,修饰茎以进行光合作用。 Spines create a moisture layer around the plant reducing the water potential gradient and thus reducing transpiration. Roots are not deeply rooted, and they are near to the surface and wide spread to collect water even from very small rains. In addition, succulents possess a very thick cuticle, which is impervious to water.
仙人掌和多肉植物有什么区别? •所有仙人掌都是多肉植物,但并非所有多肉植物都是仙人掌。 |
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