Internal pressurization and convective gas flow in some emergent freshwater macrophytes

• DOI: 10.4319/lo.1992.37.7.1420
• Publication Date: 2010-04-16T19:33:41Z
• Authors: Hans Brix; Brian K. Sorrell>; Philip T. Orr
• Keywords: Cabin pressurization; Convective mixing

Internal pressurization and convective through‐flow are demonstrated to be common attributes of wetland plants with cylindrical culms or linear leaves. Eight 14 species tested produced static internal gas pressure differentials 200–1,300 Pa relative ambient airflows 0.2 >10 cm 3 min −1 culm , depending on species. Four <100 Pa. Two did not pressurize. The driving forces gradients in temperature water vapor between the spaces atmosphere (thermal transpiration humidity‐induced pressurization). A clear diel variation flow was observed; rates were highest afternoon lowest at night, responding changes light, temperature, humidity. resistance airflow stem‐rhizome junction very high for some species, resulting a low ability convert into through rhizomes. Species potential seem have competitive advantage over that rely exclusively diffusive transport, which allows them grow deeper waters.