Structural response of marine and estuarine plants of Halophila ovalis (R. Br.) Hook. f. to long-term hyposalinity

摘要: An unusual double membrane structure, or 'annulus' located within leaf blade epidermal cells of the euryhaline seagrass Halophila ovalis may be an important site for ion transport and storage during osmotic adjustment. Cuttings marine estuarine H. were cultured 4 weeks in enriched seawater at 35‰ 25‰, respectively (the salinities which they growing time collection) 15‰ below these habitat salinities. In a second experiment, plants low salinity returned to their Paradermal sections severed leaves revealed that structure was fact tonoplast encircled by protoplast present only plants. Cell responses differed between Marine intolerant prolonged exposure (20‰). Plant mortality reached 75% 3 weeks, continued deteriorate following return (35‰). Estuarine healthy 20‰ grew well 10‰, but appeared stressed after weeks. Chloroplasts swollen few number, while number with visible vacuoles increased under conditions. Leaf senescence accelerated approximately 1 week when compared control grown surface area, internode length rhizome diameter decreased salinity. These structural changes reversed 25‰ Differences tolerance result from acclimation emergence ecotypes, as occurs algae wide distributions.