cohesion–tension theory of sap ascent

Examples of cohesion–tension theory of sap ascent in the following topics:

• Movement of Water and Minerals in the Xylem

  • At night, when stomata close and transpiration stops, the water is held in the stem and leaf by the cohesion of water molecules to each other as well as the adhesion of water to the cell walls of the xylem vessels and tracheids.
  • This is called the cohesion–tension theory of sap ascent.
  • The cohesion-tension theory explains how water moves up through the xylem.
  • The formation of gas bubbles in the xylem is detrimental since it interrupts the continuous stream of water from the base to the top of the plant, causing a break (embolism) in the flow of xylem sap.
  • The cohesion–tension theory of sap ascent is shown.

• The Functionalist Perspective

  • According to the functionalist perspective, race and ethnicity are two of the various parts of a cohesive society.
  • Functionalism addresses society as a whole in terms of the function of its constituent elements; namely norms, customs, traditions, and institutions.
  • In the 1960s, functionalism was criticized for being unable to account for social change, or for structural contradictions and conflict (and thus was often called "consensus theory"), and for ignoring systematic inequalities including race, gender, and class, which cause tension and conflict.
  • It is less well-adapted to understanding individual discrimination because it ignores the inequalities that cause tension and conflict.
  • During the turbulent 1960s, functionalism was often called "consensus theory," criticized for being unable to account for social change or structural contradictions and conflict, including inequalities related to race, gender, class, and other social factors that are a source of oppression and conflict.

• Elton Mayo

  • The research he conducted under the Hawthorne Studies of the 1930s showed the importance of groups in affecting the behavior of individuals at work.
  • Where norms of cooperation and higher output were established because of a feeling of importance, physical conditions or financial incentives had little motivational value.
  • He suggested a tension between workers' "logic of sentiment" and managers' "logic of cost and efficiency" which could lead to conflict within organizations.
  • Cohesive and good leadership is needed to communicate goals and to ensure effective and coherent decision making.
  • However, this theory has been contested, as Mayo's purported role in the human relations movement has been questioned.