Transpiration refers to the loss of water by plants through tiny pores called stomata. In addition, at times, plants lose water through stems, flowers, branches, or roots. Depending on the particular plant’s adaptation, the stomata location on the leaves surface varies. For most plants, the stomata are located on the undersides of the foliage to minimize the rate of loss during harsh climatic conditions.
Additionally, the stomata have guard cells, which open or close to regulate the transpiration level. Transpiration facilitates the cooling of plants. In addition, the process regulates the rate of absorption of water in the roots, intake of mineral nutrients, and the osmotic pressure within the plant. Some of the factors, which influence this process, include temperature, low humidity and other factors that induce transpiration (Böhm, 2010).
Capillary action facilitates the flow of water from the roots to the shoot in plants. Initially, the roots absorb water by the process of osmosis due to the variation in the concentration of the water level between the soil and roots. For tall plants, the movement of water and nutrients to the upper parts is facilitated by the plants’ reduction of hydrostatic pressure. In this regard, the pores between the soil particles are large compared to the roots pores.
Therefore, the plants absorb water and maintain a consistent supply. Because of the availability of water at the leaves, plants attempt to regulate their moisture content with respect to the surrounding conditions. The main sources of energy for this process include temperature, humidity, wind and incidence of light (Mansfield, 1993).
Temperature levels influence the rate at which transpiration occurs. At high temperatures, plants receive heat, which creates the need for cooling on the upper parts of the leaves. Because of this process, the plants moisture content decreases, and water moves through the pores causing cooling. As a result, the heat vaporizes the water leading to its release into the atmosphere.
Low humidity leads to a difference in vapor concentration occurring between the leaves’ surface and the atmosphere. Water moves by the process of diffusion between two regions with different concentrations. This is influenced by the decrease in the moisture content in the upper side of the leaves. The water release out of the pores is lost to the atmosphere leading to the maintenance of balanced humidity between the leaves and the atmosphere.
Wind refers to the movement of air. Concerning plants, winds play a crucial role in facilitating the process of transpiration. The movement of air causes the difference in water concentration between the leaves and the atmosphere. This is due to the decrease of moisture concentration in the leaves upper part. As a result, water is lost through the wind energy to the atmosphere.
The incidence of light causes heating on the surface of leaves and the decrease in moisture level. The moisture in the leaves is lost through the pores on the upper surface. This causes cooling. The moisture is lost to the atmosphere through the transpiration process.
With the analysis of the sources of energy that influence transpiration, the rate of transpiration depends on the adaptation of a particular plant (Smith, 2006). Regarding the plants in a high-moisturized environment, they have a large number of stomata, which contribute to the high rate of transpiration facilitated by the sources of energy. On the other hand, plants in a dry environment have adaptation characteristics that facilitate low levels of transpiration.
References
Böhm, C. (2010). Transpiration. München: GRIN Verlag GmbH.
Mansfield, T. A., Davies, W. J., & Leigh, R. A. (1993). The transpiration stream. New York: Royal Society.
Smith, T. M., & Smith, R. L. (2006). Elements of ecology (6. ed.). San Francisco, Calif. [u.a.: Pearson / Benjamin Cummings.