COMPARATIVE-STUDY OF THE LACUNAR SYSTEMS OF EICHHORNIA-CRASSIPES (MART.) SOLMS. E PISTIA-STRATIOTES L

The lacunar system of aquatic plants is related to internal transport of gases, supplying oxygen to submerged or underground organs. Eichhor nia crassipes and Pistia stratiotes are emergent macrophytes that occu r in poluted waters, with low oxygen content. In order to verify the c ontinuity of their lacunar systems, the anatomy of vegetative organs w ere studied in both species. It was observed that all organs present w ell developed lacunar system. However, only E. crassipes has a continu ous lacunar system. The importance of this system is discussed.