%0 Journal Article
%T Gas Exchange Rates of Texas Persimmon (&lt;i&gt;Diospyros texana&lt;/i&gt;) in Central Texas Woodlands
%A Matthew B. Grunstra
%A Oscar W. Van Auken
%J American Journal of Plant Sciences
%P 329-348
%@ 2158-2750
%D 2024
%I Scientific Research Publishing
%R 10.4236/ajps.2024.155024
%X &lt;i&gt;Diospyros texana&lt;/i&gt; (Texas persimmon) is a secondary species in most &lt;i&gt;Junip&lt;/i&gt;&lt;i&gt;e&lt;/i&gt;&lt;i&gt;rus ashei/Quercus fusiformis&lt;/i&gt;&lt;i&gt; &lt;/i&gt;woodlands in central Texas. It has high density, but plants are mostly in the community understory. Light response curves at ambient and elevated levels of CO&lt;sub&gt;2&lt;/sub&gt; and temperature were measured for &lt;i&gt;D. texana&lt;/i&gt;. The &lt;i&gt;A&lt;/i&gt;&lt;i&gt;&lt;sub&gt;net&lt;/sub&gt;&lt;/i&gt; (photosynthetic rate) increased significantly as both light level and CO&lt;sub&gt;2&lt;/sub&gt; levels increased but not temperature. The &lt;i&gt;A&lt;/i&gt;&lt;i&gt;&lt;sub&gt;max&lt;/sub&gt;&lt;/i&gt; (maximum photosynthetic rate) of &lt;i&gt;D. texana&lt;/i&gt; in full sun at elevated levels of CO&lt;sub&gt;2&lt;/sub&gt; was increased for all treatments. Stomatal conductance increased with levels of CO&lt;sub&gt;2&lt;/sub&gt; but only if the interaction was removed from the model. Intercellular levels of CO&lt;sub&gt;2&lt;/sub&gt; increased with both temperature and CO&lt;sub&gt;2&lt;/sub&gt; treatments as did water use efficiency (WUE). Furthermore, light saturation (&lt;i&gt;L&lt;/i&gt;&lt;i&gt;&lt;sub&gt;sat&lt;/sub&gt;&lt;/i&gt;) increased with CO&lt;sub&gt;2&lt;/sub&gt; treatments and light compensation (&lt;i&gt;L&lt;/i&gt;&lt;i&gt;&lt;sub&gt;cp&lt;/sub&gt;&lt;/i&gt;) increased with temperature. The dark respiration (&lt;i&gt;R&lt;/i&gt;&lt;i&gt;&lt;sub&gt;d&lt;/sub&gt;&lt;/i&gt;) increased with both temperature and CO&lt;sub&gt;2&lt;/sub&gt; treatments. Markov population models suggested &lt;i&gt;D. texana&lt;/i&gt; populations would remain ecologically similar in the future. However, sub-canopy light levels and herbivory should be considered when examining population projections. For example, &lt;i&gt;Juniperus ashei&lt;/i&gt; juveniles are not recruited into any canopy unless there are high light levels. Herbivory reduces the success of &lt;i&gt;Quercus&lt;/i&gt; juveniles from reaching the canopy. These factors do not seem to be a problem for &lt;i&gt;D. texana&lt;/i&gt; juveniles which would allow them to reach the canopy without need of a high light gap and are not prevented by herbivory. Thus, &lt;i&gt;Juniperus/Quercus&lt;/i&gt; woodlands will change in the future to woodlands with &lt;i&gt;D. texana&lt;/i&gt; a more common species.
%K Replacement Dynamics
%K Ecological Succession
%K CO&lt
%K sub&gt
%K 2&lt
%K /sub&gt
%K Concentrations
%K Temperature Levels
%K Photosynthetic Rates
%K Drought Tolerance
%K Herbivory
%K Species Replacement
%K Encroachment
%K Juniper
%U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=133340