scholarly journals Enhanced growth of Juniperus thurifera under a warmer climate is explained by a positive carbon gain under cold and drought

2012 ◽  
Vol 32 (3) ◽  
pp. 326-336 ◽  
Author(s):  
T. E. Gimeno ◽  
J. J. Camarero ◽  
E. Granda ◽  
B. Pias ◽  
F. Valladares
Keyword(s):  
Carbon Gain ◽  
Juniperus Thurifera

Effects of moisture supply in the dry season and subsequent defoliation on persistence of the savanna grasses Themeda triandra, Heteropogon contortus and Panicum maximum

1992 ◽  
Vol 43 (2) ◽  
pp. 241 ◽  
Author(s):  
JJ Mott ◽  
MM Ludlow ◽  
JH Richards ◽  
AD Parsons
Keyword(s):  
Growing Season ◽  
Close Correlation ◽  
Dry Season ◽  
Carbon Gain ◽  
Panicum Maximum ◽  
Wet Season ◽  
Themeda Triandra ◽  
Heteropogon Contortus ◽  
Moisture Conditions ◽  
Sheath Material

The close correlation between grazing-induced mortality and major climatic patterns in Australian savannas, led us to the hypothesis that moisture conditions during the dry, non-growing season could affect sensitivity to grazing in the subsequent growing season. Using three widespread savanna species (Themeda triandra, Heteropogon contortus and Panicum maximum), this hypothesis was tested experimentally and the mechanisms controlling this response examined and quantified. In T. triandra drought during the dry season led to major mortality in defoliated plants in the next growing season. This mortality was caused by a synchrony of tillering at the commencement of the wet season, leaving few buds for replacement once parent tillers were killed by defoliation. T. triandra was also the most sensitive species to defoliation. This sensitivity was due to the poor ability of the plant to maintain positive carbon gain after defoliation. Several factors contributed to this poor ability, including: low total photosynthetic rate, low specific leaf area, and a large proportion of sheath material with poor photosynthetic capacity remaining after cutting. Both H. contortus and P. maximum growing under irrigated and fertilized conditions did not display any effects of previous moisture treatments when defoliated during the next wet season and were much less sensitive to defoliation than T. triandra.

Oxygenated diterpenes and other constituents from Moroccan Juniperus phoenicea and Juniperus thurifera var. africana

2004 ◽  
Vol 65 (17) ◽  
pp. 2507-2515 ◽  
Author(s):  
Alejandro F. Barrero ◽  
José F. Quı́lez del Moral ◽  
M. Mar Herrador ◽  
Mohamed Akssira ◽  
Ahmed Bennamara ◽  
...  
Keyword(s):  
Juniperus Thurifera ◽  
Juniperus Phoenicea

Valorisation des huiles essentielles de Juniperus thurifera et de Juniperus oxycedrus du Maroc

2010 ◽  
Vol 8 (3) ◽  
pp. 166-170 ◽  
Author(s):  
N. Mansouri ◽  
B. Satrani ◽  
M. Ghanmi ◽  
L. El ghadraoui ◽  
A. Aafi ◽  
...  
Keyword(s):  
Huiles Essentielles ◽  
Juniperus Thurifera ◽  
Juniperus Oxycedrus

Lichen carbon gain under tropical conditions: water relations and CO2 exchange of Lobariaceae species of a lower montane rainforest in Panama

2004 ◽  
Vol 36 (5) ◽  
pp. 329-342 ◽  
Author(s):  
Otto L. LANGE ◽  
Burkhard BÜDEL ◽  
Angelika MEYER ◽  
Hans ZELLNER ◽  
Gerhard ZOTZ
Keyword(s):  
Water Relations ◽  
Carbon Fixation ◽  
Nitrogen Concentration ◽  
Carbon Gain ◽  
Carbon Loss ◽  
Natural Conditions ◽  
Low Light ◽  
Green Algal ◽  
Tropical Conditions ◽  
Montane Rainforest

Diel (24-h) time courses of microclimate, water relations, and CO2 exchange were measured under quasi-natural conditions at a forest edge in a lower montane, tropical rainforest in Panama for six Lobariaceae (Lobaria crenulata, L. dissecta, Pseudocyphellaria aurata, P. intricata, Sticta sublimbata, S. weigelii). Responses to experimentally controlled water content (WC), photosynthetic photon fluence rate (PPFR), and temperature were studied in most detail with P. aurata.Photosynthesis was well adapted to high temperatures, and all species exhibited ‘shade plant’ characteristics with low light compensation points and low light saturation. Lobaria and Pseudocyphellaria species suffered from a strong depression of net photosynthesis (NP) at suprasaturating WC; suprasaturation depression was less in cyphellate Sticta species.Photosynthetic capacity correlated with thallus nitrogen concentration, and maximal NP rates of the cyanobacterial Sticta species was 4 to 5 times higher than that of the green algal Lobaria species. However, high rates of NP were uncommon and brief events under natural conditions; the different environmental factors were rarely optimal simultaneously. Similar to earlier observations with other rainforest lichens, NP ceased during the period of highest irradiation on most days due to desiccation. During moist periods low light often limited carbon fixation, and high thallus hydration was often detrimental to NP. In spite of these limitations the maximal daily integrated net photosynthetic carbon income (ΣNP) was quite high especially for the Sticta species [17·3 and 24·1 mgC (gC)−1 day−1 for S. sublimbata and S. weigelii, respectively]. High nocturnal carbon loss, due to high night temperatures and continuous hydration, resulted in frequent negative diel carbon balances (ΣC) in all species. The average nocturnal carbon loss amounted to 83 and 70% ΣNP for P. aurata and P. intricata, respectively and to 64 and 59% of ΣNP for S. sublimbata and S. weigelii, respectively. Their average diel ΣC was as high as 3·7 and 5·3 mgC (gC)−1 day−1. In contrast, ΣC was much lower for the other species, it amounted to only 0·18 mgC (gC)−1 day−1 for L. crenulata. Thus, the Sticta species stood out amongst the species studied for their most successful adaptation of photosynthetic productivity to the habitat conditions in the lower montane rainforest.

Competitive strategies in adult beech and spruce: space-related foliar carbon investment versus carbon gain

Oecologia ◽  
2005 ◽  
Vol 146 (3) ◽  
pp. 337-349 ◽  
Author(s):  
I. M. Reiter ◽  
K. -H. Häberle ◽  
A. J. Nunn ◽  
C. Heerdt ◽  
H. Reitmayer ◽  
...  
Keyword(s):  
Carbon Gain ◽  
Competitive Strategies
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