PT  - JOURNAL ARTICLE
AU  - Sobrado, M. A.
TI  - Leaf characteristics and diurnal variation of chlorophyll fluorescence in leaves of the 'bana' vegetation of the amazon region
DP  - 2008 Jun 1
TA  - Photosynthetica
PG  - 202--
VI  - 46
IP  - 2
AID - 10.1007/s11099-008-0033-9
IS  - 03003604
AB  - In six dominant species of the Amazonian 'Bana' vegetation, leaf blade characteristics, pigment composition, and chlorophyll (Chl) fluorescence parameters were measured in young and mature leaves under field conditions. Leaf δ&lt;sup&gt;13&lt;/sup&gt;C was comparable in the six species, which suggested that both expanding and expanded leaves contained organic matter fixed under similar intercellular and ambient CO&lt;sub&gt;2&lt;/sub&gt; concentration (C &lt;sub&gt;i&lt;/sub&gt;/C &lt;sub&gt;a&lt;/sub&gt;). High leaf C/N and negative δ&lt;sup&gt;15&lt;/sup&gt;N values found in this habitat were consistent with the extreme soil N-deficiency. Analysis of Chl and carotenoids showed that expanding leaves had an incomplete development of photosynthetic antenna when compared to adult leaves. Dynamic inactivation of photosystem 2 (PS2) at midday was observed at both leaf ages as F&lt;sub&gt;v&lt;/sub&gt;/F&lt;sub&gt;m&lt;/sub&gt; decreased compared to predawn values. Adult leaves reached overnight F&lt;sub&gt;v&lt;/sub&gt;/F&lt;sub&gt;m&lt;/sub&gt; ratios typical of healthy leaves. Overnight recovery of F&lt;sub&gt;v&lt;/sub&gt;/F&lt;sub&gt;m&lt;/sub&gt; in expanding leaves was incomplete. F&lt;sub&gt;0&lt;/sub&gt; remained unchanged from midday to predawn and F&lt;sub&gt;v&lt;/sub&gt; tended to increase from midday to predawn. The recovery from midday depression observed in adult leaves suggested an acclimatory down-regulation associated with photo-protection and non-damage of PS2.