The photosynthetic characteristics of saplings of eight canopy tree species in a disturbed neotropical rain forest

Authors: Vera, N.E., Finegan, B. and Newton, A.C.

Journal: Photosynthetica

Volume: 36

Issue: 3

Pages: 407-422

ISSN: 0300-3604

DOI: 10.1023/A:1007076103204

Abstract:

Foliar gas exchange characteristics, understorey microclimate, and crown irradiation were assessed for saplings of eight canopy tree species in two plots of neotropical rain forest with different degrees of canopy opening. Species studied belonged to different putative guilds: shade intolerants (both short-lived - pioneers - and long-lived), intermediates, and shade-tolerants. A considerable overlap was recorded between species in values of the photosynthetic rate per unit leaf area (P(N)). The highest median P(N) (1.26 μmol m-2 s-1) was recorded in the pioneer Croton killipianus, while slightly lower median values were recorded in Simarouba amara and Pentaclethra macroloba, and markedly lower values in two species of Vochysiaceae (Qualea paraense and Vochysia ferruginea), both putative intolerants. Highest median stomatal conductance (g(s)) was also shown by C. killipianus, while S. amara, P. macroloba, and L. procera exhibited intermediate values, and the lowest g(s) was shown by V. ferruginea and Q. paraense. Overall irradiance and crown irradiation, P(N), and g(s) of saplings were higher in the plot which had previously received a silvicultural treatment. Most values of photosynthetic photon flux density (PPFD) were <100 μmol m-2 s-1 in both plots, with short-lived peaks of up to 2000 μmol m-2 s-1 in the treated plot. When the relationship between P(N) and irradiance (I) was examined by fitting P(N)/I curves, the degree of fit varied markedly between species, values of the regression coefficient r2 were between 0.09 and 0.51. No significant differences between species were recorded in P(max) and species also demonstrated little variation in the predicted values of dark respiration (R(D)), values varying between -0.51 and -1.46 μmol m-2s-1 in Q. paraense and Minquartia guianensis, respectively. Fitted values of apparent quantum efficiency were also fairly uniform, generally falling within the range 0.02-0.03 mol(CO2) mol-1(photon).

Source: Scopus

The photosynthetic characteristics of saplings of eight canopy tree species in a disturbed neotropical rain forest

Authors: Vera, N.E., Finegan, B. and Newton, A.C.

Journal: PHOTOSYNTHETICA

Volume: 36

Issue: 3

Pages: 407-422

eISSN: 1573-9058

ISSN: 0300-3604

DOI: 10.1023/A:1007076103204

Source: Web of Science (Lite)

Preferred by: Adrian Newton