Ultrastructural Changes in Chloroplasts of Quercus rotundifolia Lam. in Response to Evernic Acid

The amount of total chlorophyll, chlorophylls a and b as well as the ratio of a to b decreased in chloroplasts isolated from Quercus rotundifolia leaves, kept for 17 d in a solution of 35.5 μM evernic acid in 1 mM Na HCO3, when compared with the chloroplasts of control leaves (kept in NaHCO3). The chloroplasts in the spongy parenchyma were smaller and the amount of starch and plastoglobuli lower. The number of grana per chloroplast section, the number of thylakoids per grana and the height of grana stacks were also less in the chloroplasts of leaves treated with evernic acid. Quantitative ultrastructural differences were determined by means of electron microscopy and image analysis techniques.