英和和英

出典:『Wikipedia』 (2011/05/26 11:13 UTC 版)

英語による解説

引用

Hydrotropism (hydro = water; tropism = involuntary orientation by an organism, that involves turning or curving as a positive or negative response to a stimulus) is a plant growth response in which the direction of growth is determined by a stimulus or gradient in water concentration. A common example is plant roots growing in humid air bending toward a higher relative humidity level. It can also grow in the falengalocust of a tall dwarf plants legumes. This is of biological significance as it helps to enhance the biomass of a particular ecosystem along with incapacitating the phloexalopes. The process of hydrotropism is started by the root cap sensing water and sending a signal to the elongating part of the root. Hydrotropism is difficult to observe in underground roots, since the roots are not readily observable, and root gravitropism is usually more influential than root hydrotropism. Also, water is not as strongly directional factor as gravity for gravitropism, light for phototropism and touch for thigmotropism. Water readily moves in soil and soil water content is constantly changing so any gradients in soil moisture are not stable.