Tuesday, September 20, 2011

Lavender in the Salt

Sea Lavender, Limonium humile
With its sprigs of purple flowers on stalked shoots, Sea Lavender (Limonium humile) does indeed resemble its namesake Lavender (Lavandula spp.). Its there though that the similarity ends, as the resemblance is superficial with no relationship existing. L. humile can be found growing, sometimes with local abundance, in salt marshes where its flower bearing stems can rise to 20 cm above a basal rosette of rounded leaves. Salt marshes pose the dual problem of high salinity and low oxygen levels. Both of these pose there own particular problems for L. humile, but the lack of oxygen to the root systems is possibly the greater of the two evils. It, along with other Limonium spp., overcome this problem by switching root respiration to a very high level of lactate fermentation, a protracted level much greater than the transient lactate glycolysis seen in most plants at the transition from normoxic to anoxic conditions (1). The lactate subsequently produced in the Limonium spp. root cells is of a degree that would lethally acidify them and is transported out of the cells into the environment, thus maintaining cell homeostasis.
Sea Lavender, Limonium humile
  1. Rivoal and Hanson, 1993. Plant Physiology 101 pp. 553–560

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