The aveolus is surrounded by capillaries. So capillaries carry deoxygenated blood to the alveolus where the oxygen from the alveolus diffuses into the blood in the capillaries. The deoxygenated blood is now oxygenated and is carried out of the lung via capillaries that then merge into the pulmonary vein.
In other words, alveolus does not have oxygenated blood it just puts oxygen into the deoxygenated blood hat this brought in.
Water quality testing would be the best approach.
One is through turgidity. this occurs before ground tissue ( collenchyma and sclerenchyma cells) become well developed to give structural support to the plant as it grows bigger. The xylem tissue (composed of rigid tissue) of the young plant render this support and also maintaining osmotic turgidity of the surrounding plant cells.
