A SURVEY OF ANATOMICAL ADAPTATIONS IN ROMANIAN HALOPHYTES. TOWARDS AN ECOLOGICAL INTERPRETATION

摘要

A number of 50 halophytes vegetating on salty areas from Romania has been anatomically investigated. These species present various anatomical adaptations that are correlated with environmental factors: soil salinity and humidity. The relevance and significance of each adaptation is discussed in accordance with ecological factors, regarded naturally as a part of salinized ecosystems, which would have contributed - during the evolution - to induce such responses in halophytes. The great diversity in the nature of saline areas in Romania provides an ideal scenario for studying halophytes' adaptations. Thus, various anatomical responses to environmental factors are described and discussed. Succulence occurs both in hygro-halophytes, as well in xero-halophytes, with precise ecological significance in both situations. The successive cambia phenomenon has been evidenced in chenopods species and an evolutionary and ecological value has been presumably attributed to it. Secretory structures are also present in a distinct class of halophytes, cryno-halophytes, and seem to be an efficient mechanism in salt removal from aerial organs of halophytes. Kranz anatomy, a special foliar configuration related to C_4 photosynthesis has been identified in several species, especially from Chenopodi-aceae. Bulliform cells, a quite common feature in many grasses, were evidenced in amphibious halophytes, a special and new described sub-class in halophytes.