Lab Two: Flower Our video depicts that all organisms are aqueous, and that flowers have special ways to prevent water loss or evapotranspiration. Some of the ways that plants prevent water loss is through thorns and hair on leaves to create shade; others have created a thick cuticle or a waxy layer to prevent water from entering or exiting the leaf. During the winter many plants appear to die off, however, for some plants this is untrue. Annuals are plants that return year after year and the way they accomplish this is through the use of bulbs. The bulbs store water and nutrients during the cold winter months while the ground is frozen as well as the water molecules in the soil. Seeds are also another way plants survive the winter. The seeds lie dormant during the winter and wait for the ground to thaw to start gathering the nutrients needed to grow. These are just a few ways that plants prevent evapotranspiration, and these are the ones that we cover in our video; however there are other ways too. The use of stomata, for example, allows gas to escape but they also help prevent water from escaping by having the guard cells close when not in use.

Here we see evolutionary adaptations which plants use to conserve water. Cacti in the desert have survived because their leaves have evolved into non-photosynthetic spines. Therefore, these spines have no stomata to preform evapotranspiration. Evapotranspiration is the release of water vapor during photosynthesis. When stomata on a leaf are open, water is released. Pine leaves have become needle like, decreasing exposure of stomata. They also are surrounded by a waxy cuticle and the stomata themselves are sunken. This prevents water loss during the Pine's dry season of winter. Some plants such as maples lose their photosynthetic leaves all together during the cold months as to cease photosynthesis and conserve water. Tiny, hair like trichomes are present in some plants amongst stomata as to prevent excess water escape and keep relative humidity around stomata high. All of these adaptations have come about because of evolutionary pressures placed on plants. Aquisition and conservation of water is essential to plant life.

The Hydrologic Cycle (or the Water Cycle) is a cycle of evaporation, evapotranspiration, precipitation and infiltration. The sun heats bodies of waters such as oceans and lakes, which causes the water to evaporate and form water vapor. Water vapor is also transpired from trees and soil. The collection of water vapor condenses to form clouds, which move around the globe by air currents. With the right conditions, clouds precipitate; some of the water absorbs into the ground to form an aquifer, and some runs into lakes and streams. This is a continuous cycle, however, human settlement has put a damper on the cycle. For example, industrial waste and toxins can pollute air and water, the building of dams disrupts the natural flow of water, the building of roads cause erosion, to name a few. In order to prevent further harm to the environment, we should consider the consequences of our actions to create a more eco-friendly environment for our future.

Weather observing stations in the North Carolina Environment and Climate Observing Network (ECONet) are maintained by the State Climate Office at NC State University. In addition to standard meteorological parameters, ECONet stations also measure solar radiation, photosynthetically active radiation, evapotranspiration, soil moisture and soil temperature. We install most atmospheric instruments at 2m with the option of also doing 10m. Data go into the CRONOS database, a high-resolution surface weather archive used by researchers, forecasters and the general public for decision support. NC ECONet: http://www.nc-climate.ncsu.edu/econet/ CRONOS database: http://www.nc-climate.ncsu.edu/cronos/

Water Relations are a driving force in the natural selection among plants. Since photosynthesis removes water through evapotranspiration plants must have mechanisms to conserve water. Bulbs store water so that plants can survive at times when water is unavailable. Plants like Salvina have rhizines that help anchor that plant and photosynthetic bacteria that help to provide the plant with nutrients. Elodea is a plant that floats freely in water and therfore has not vascular system or roots. Plants can adapt to the constraints of water by having hair like leaves. Reduction of leaf size is another adaptation to the scarcity of water. Pines internal anatomy prevents water loss, there stomata are sunken, there waxy cuticle is thick which all help to conserve water. The cacti have no photosynthetic capacity. Ultimately plants must have adaptations to obtain and conserve water.

This is an introduction video to a series dedicated to weather based irrigation controller education.

This is animation of monthly evapotranspiration (mm/month) for 1986, based on satellite observations of vegetation activity and ground-based measurements of meteorological conditions. For more information see Fisher JB and Tu KP, Baldocchi DD. 2008. Global estimates of the land-atmosphere water flux based on monthly AVHRR and ISLSCP-II data, validated at 16 FLUXNET sites. Remote Sensing of Environment 112(3): 909-919.

Limiting Factors and Biogeochemical Cycles (Prof. Penny Chisholm) View the complete course: http://ocw.mit.edu/7-014S05 License: Creative Commons BY-NC-SA More information at http://ocw.mit.edu/terms More courses at http://ocw.mit.edu