[Ultrastructural changes caused by a herbicide, picloram in technical dosage (70,4%), in a plankton alga, Dunaliella bioculta (Volvocales)].

A study on the effects of an auxin-like herbicide-picloram (techinical grade 70,4%)--was carried out on a planktonic green Alga, Dunaliella bioculata. At concentrations about 250 mug/ml, the cellular growth decreases while at 400 mug/ml it is completely inhibited. Concentrations of 250-300 mug/ml induce the fall of flagella and an increase of the cellular volume; granulous inclusions-nuclear bodies-are observed inside the nucleus; Golgi apparatus is abnormally developed. The vascuolar system is particularly disturbed: its volume increases; vesicles, cytoplasmic and membrane fragments and osmiophilic granulations can be observed inside vacuoles under the electron microscope.