根是高等植物在长期适应陆地生活过程中发展起来的一种向下生长的营养器官。它是由幼胚的胚根发育而成。其发达程度和生态类型因所处环境不同,而差异很大,根的功能亦各不相同。一般常见的根的生态类型有:1.直根。它是植物茎在土壤中的继续,通常以其尖端垂直地向地下生长。按起源来说,是由胚根发育成为主根。这种根系向下钻的能力很强。如沙漠中有一种植物叫“骆驼刺”属于直根系,它可以钻入 Root is a downward growing vegetative organ developed by higher plants during their long-term adaptation to terrestrial life. It is developed from the radicle of the immature embryo. The level of their development and ecological types of different environments, but very different, the root function is also different. Common ecological types of roots are: 1. Straight root. It is the continuation of plant stems in the soil, often growing vertically underground with its tips. By origin, is the development of radicle root. The ability of this root to drill down is strong. If the desert has a plant called “camel thorn” is a straight root, it can drill into