<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>G. Bowes</dc:contributor>
  <dc:creator>Jon E. Keeley</dc:creator>
  <dc:date>1982</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;The submerged aquatic plant&amp;nbsp;&lt;/span&gt;&lt;i&gt;Isoetes howellii&lt;/i&gt;&lt;span&gt;&amp;nbsp;Engelmann possesses Crassulacean acid metabolism (CAM) comparable to that known from terrestrial CAM plants. Infrared gas analysis of submerged leaves showed&amp;nbsp;&lt;/span&gt;&lt;i&gt;Isoetes&lt;/i&gt;&lt;span&gt;&amp;nbsp;was capable of net CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;uptake in both light and dark. CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;uptake rates were a function of CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;levels in the medium. At 2,500 microliters CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;per liter (gas phase, equivalent to 1.79 milligrams per liter aqueous phase),&amp;nbsp;&lt;/span&gt;&lt;i&gt;Isoetes&lt;/i&gt;&lt;span&gt;&amp;nbsp;leaves showed continuous uptake in both the light and dark. At this CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;level, photosynthetic rates were light saturated at about 10% full sunlight and were about 3-fold greater than dark CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;uptake rates. In the dark, CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;uptake rates were also a function of length of time in the night period. Measurements of dark CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;uptake showed that, at both 2,500 and 500 microliters CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;per liter, rates declined during the night period. At the higher CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;level, dark CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;uptake rates at 0600 h were 75% less than at 1800 h. At 500 microliters CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;per liter, net CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;uptake in the dark at 1800 h was replaced by net CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;evolution in the dark at 0600 h. At both CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;levels, the overnight decline in net CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;uptake was marked by periodic bursts of accelerated CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;uptake. CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;uptake in the light was similar at 1% and 21% O&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;, and this held for leaves intact as well as leaves split longitudinally. Estimating the contribution of light&amp;nbsp;&lt;/span&gt;&lt;i&gt;versus&lt;/i&gt;&lt;span&gt;&amp;nbsp;dark CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;uptake to the total carbon gain is complicated by the diurnal flux in CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;availability under field conditions.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1104/pp.70.5.1455</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Oxford Academic</dc:publisher>
  <dc:title>Gas exchange characteristics of the submerged aquatic Crassulacean acid metabolism plant, Isoetes howellii</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>