Samples of Ruppia maritima collected in the lagoonar systems of Alvara
do, Sontecomapan and Nichupte were used for studying chloroplasts orie
nted movements by optical microscopy, photography and spectrophotometr
y. Three phases of chloroplast arrangement (antistrophe, parastrophe a
nd peristrophe) were observed, similar to those observed in other spec
ies. There is a relation between the movements and absorbancy.