01570nas a2200217   4500008004100000245008700041210006900128260001200197300001200209490000700221520087200228653001101100653002801111653001001139653001101149653001301160653002901173100001401202700002001216856011601236       1996                        eng d00aThe effect of increased water level on Isoetes lacustris L. in Lake Baciver, Spain0 aeffect of increased water level on Isoetes lacustris L in Lake B  c1996///  a57 - 590 v343 aTen months after flooding lake Baciver, water levels were 5.5 m higher than the previous normal and the area formally occupied by the Isoetes population was reduced. All Isoetes originally present below 0.6 m died, and only plants standing between 5.8 and 6.1 m (new depth) survived. As irradiance decreased, remaining individuals produced fewer leaves, but their biomass production was higher, as leaf length increased in response to the diminished available irradiance. Because leaf mortality was excessive, regeneration capacity, population performance and dynamics were adversely affected. In 1992, no new production occurred in Isoetes lacustris individuals surviving after the winter. We suggest that low surface oxygen levels at the water column under the ice, and total anoxia below 6 m depth, caused the demise of the I. lacustris population in Lake Baciver.10aAnoxia10aLeaf primary production10aLight10aOxygen10aPyrenees10aWater level fluctuations1 aGacia, E.1 aBallesteros, E.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-0030188498&partnerID=40&md5=76a5af33fa658c06abddf82d836c45a502382nas a2200229   4500008004100000245010700041210006900148260001200217300001600229490000700245520162100252653002601873653001101899653002401910653001601934653001201950653002101962653001901983653001602002100001802018856011602036       2004                        eng d00aRegulation of root anaerobiosis and carbon translocation by light and root aeration in Isoetes alpinus0 aRegulation of root anaerobiosis and carbon translocation by ligh  c2004///  a1102 - 11110 v273 aThe activity of alcohol dehydrogenase (ADH) was measured in corms and roots of the submerged freshwater macrophyte Isoetes alpinus Kirk. growing in situ, and related to its capacity for internal oxygen transport and to carbohydrate translocation. ADH activity was present in roots but not corms at uniform activity (0.15-0.35 × 10-6 mol g-1 fresh weight s-1) over the entire plant depth range (3-7 m depth), and was intermediate to that developed in excised roots after 1-week exposure to either dissolved oxygen at air-saturation or to anoxia. Responses of photosynthesis and root oxygen release to light intensity confirmed that shoot-to-root oxygen transport saturated at similar light intensities to photosynthetic oxygen evolution, but was positive in the dark and at irradiances below the compensation point for photosynthesis, due to contributions to transport by oxygen diffusion from the external medium. Transport of 14C-labelled photo-assimilates to roots nevertheless ceased when intact plants were exposed to a combination of leaf darkness and root external anoxia, even when high 14C concentrations were present in shoots, but remained high when the roots were provided with external oxygen. The lack of any control over permeability of the root surface to gases in this species suggested that ADH activity and reduced translocation is most likely caused by development of hypoxic tissues in the apical tissue. These results suggest that reductions in ambient light intensity may have indirect effects on I. alpinus viability by increasing the degree of root hypoxia and impairing carbon partitioning.10aAlcohol dehydrogenase10aAnoxia10aAquatic macrophytes10aAssimilates10aLacunae10aOxygen transport10aPhotosynthesis10aRespiration1 aSorrell, B.K.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-4544301436&partnerID=40&md5=3f174fe3d7839650597cfe52d3369b91