这页已由机器翻译。其他页面可能仍然显示为英文。
View in English
阿塔卡马的阳光有助于从稀薄的空气中吸取水
These videos have been matched automatically. Contact us if they are not relevant.
These videos have been matched automatically. Contact us if they are not relevant.
相关概念视频
25.0K
Though evaporation from plant leaves drives transpiration, it also results in loss of water. Because water is critical for photosynthetic reactions and other cellular processes, evolutionary pressures on plants in different environments have driven the acquisition of adaptations that reduce water loss.
In land plants, the uppermost cell layer of a plant leaf, called the epidermis, is coated with a waxy substance called the cuticle. This hydrophobic layer is composed of the polymer cutin and...
24.0K
The Earth’s hydrosphere includes all of the areas where the storage and movement of water occurs. Since water is the basis of all living processes, the cycling of water is extremely important to ecosystem dynamics.
The water cycle begins as the sun warms surface water on the land and in oceans, causing it to evaporate and enter the atmosphere as vapor. The water vapor condenses into clouds and eventually falls as precipitation in the form of rain, snow or hail.
After falling back to the...
2.0K
Change in atmospheric pressure with height is particularly interesting. The decrease in atmospheric pressure with increasing altitude is due to the decreasing gravitational force per unit area as we move away from the surface of the earth.
Assuming the air temperature is constant at a given altitude and that the ideal gas law of thermodynamics describes the atmosphere to a good approximation, one can find the variation of atmospheric pressure with height.
Let p(y) be the atmospheric pressure at...
23.4K
The xylem of vascular plants distributes water and dissolved minerals that are taken up by the roots to the rest of the plant. The cells that transport xylem sap are dead upon maturity, and the movement of xylem sap is a passive process.
Tracheids and vessel elements transport xylem sap
Tracheary elements are the transport cells of the xylem. They lack cytoplasm and organelles when they are mature and are considered part of the apoplast of the plant because they connect directly with the...
203
Surface tension is a fundamental property of fluids, occurring at the boundary between a liquid and a gas or between two immiscible liquids. This phenomenon arises from the cohesive forces between molecules at the fluid's surface, creating an effect similar to a stretched elastic membrane. Inside each fluid, molecules are equally attracted in all directions by neighboring molecules, but surface molecules experience a net inward force, resulting in surface tension.
Surface tension varies...
18.0K
Overview
Weather refers to the current state of atmospheric conditions at a specific time and place. Weather is temporary and is influenced by the interactions between the sun, atmosphere (gases around the Earth), hydrosphere (the water bodies of the Earth), and geosphere (the land portion of the Earth). As all of these factors differ across location and time, different weather can be observed across the planet.
Solar Radiation and the Greenhouse Effect
Solar radiation penetrates the...