Daily and seasonal trends of gas exchange in Pistacia lentiscus L.

Abstract

The spring-summer photosynthetic behaviour of Pistacia lentiscus, a spontaneous evergreen bush of the Mediterranean macchia, was followed during two consecutive years. Outdoor measurements were carried out monthly in the period from May to September in the years 2004 and 2005. Mean values of net photosynthesis (P N ) of external tests show a typical daily trend: a rise until the maximum followed by a decline of assimilation with lower values maintained until the end of day. External data were validated by light-response curves, obtained under different thermal regimes in controlled conditions. External trials and measures in controlled conditions confirm an elevated photosynthetic activity below 30°C and a decrease over that limit. The results obtained evidence that the CO 2 assimilation of the P. lentiscus is influenced by stressful temperatures. The ecophysiological response to this limiting factor is an adaptation that concentrates on the photosynthetic activity in the hours of the day and in the periods of the year in which temperatures are more favourable.

PHOTOSYNTHETIC PERFORMANCE AND LEAF WATER POTENTIAL OF GULUPA (Passiflora edulis Sims, PASSIFLORACEAE) IN THE REPRODUCTIVE PHASE IN THREE LOCATIONS IN THE COLOMBIAN ANDES

“…In the three locations, the environmental conditions during the morning favored an increase in the WUE e due to the fact that there are suitable radiation for an increase in photosynthesis while the VPD, temperature, and humidity conditions do not hazard an excessive loss of water by the leaf surface (Bucci et al, 2003;Zweifel et al, 2007;Mengistut et al, 2011). This has also been observed in plants in temperate (Bassow and Bazzas, 1998), Mediterranean (Chaumont et al, 1994;Gatti and Rossi, 2010) and tropical Savanna zones (Eamus et al, 1999).…”

Impacts of scenarios RCP4.5 and RCP8.5 on plant physiology in Tapajos National Forest in the Brazilian Amazon using the ED2.2 model

“…Plant respiration can increase exponentially with increasing temperature, however, photosynthetic rates are known to increase until they reach the ideal temperature and then decrease (Fitter 1981). For example, the photosynthetic activity of Pistacia lentiscus in the field was high when the temperature was below 30° C, and decreased above this limit, showing that the increase in temperature influences the assimilation of CO 2 (Gatti et al 2010).…”