Browsing by Author "Werner, C."
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- Invasão por esteva e seca: qual o efeito nas árvores e ecossistema ?Publication . Caldeira, M.C.; Lecomte, X.; David, T.S.; Pinto, J.G.; Bugalho, M.N.; Werner, C.
- Montado com esteva: qual o efeito da disponibilidade de água para as árvores?Publication . Caldeira, M.Conceição; Lecomte, X.; David, T.S.; Werner, C.; David, J.S.; Rye, R.
- Restoration of a limestone quarry: effect of soil amendments on the establishment of native Mediterranean sclerophyllous shrubsPublication . Clemente, A. S.; Werner, C.; Máguas, C.; Cabral, M. S.; Martins-Loução, M. A.; Correia, O.Limestone quarries are spread over theMediterranean Basin and have a strong environmental impact on the landscape, causing vegetation losses and soil losses. A reclamation project was conducted in a limestone quarry, situated in Arra´bida Natural Park (southwest Portugal), that is dominated by mediterranean vegetation. Revegetation was conducted using three evergreen sclerophyllous shrub species (Ceratonia siliqua, Olea europaea, and Pistacia lentiscus), and new techniques were assayed to improve plant water status and nutrient status during the first phases after plantation. A water-holding polymer (gel), fertilizer, and mycorrhiza inoculum were applied in a factorial experiment in a randomized complete block design. The success of these techniques was evaluated during 1.5 years, through monitoring of growth and ecophysiology of plants. Plant survival was high, the lowest values (95%) being recorded in C. siliqua. There were species-specific responses to the treatments applied. Ceratonia siliqua showed the highest growth rates and was the only species with growth stimulated by fertilizer application. However, the application of fertilizer induced changes in leaf characteristics of the other two species, increasing chlorophyll and nitrogen contents. Mycorrhiza inoculumhad no effect on plant response. The addition of the water-holding polymer induced higher midday plant water potentials in C. siliqua, O. europaea, and P. lentiscus, but in the latter two species the simultaneous addition of gel and fertilizer induced the lowest water potentials. The addition of fertilizer and gel is recommended in future revegetation programs but not the combination of both when revegetating with O. europaea and P. lentiscus. The results of this experiment indicate that the use of these mediterranean species, adapted to nutrient and water stress, can circumvent harsh conditions of the quarry.
- Volatile diterpene emission by two Mediterranean Cistaceae shrubsPublication . Yáñez-Serrano, A.M.; Fasbender, L.; Kreuzwieser, J.; Dubbert, D.; Haberstroh, S.; Lobo-do-Vale, R.; Caldeira, M.C.; Werner, C.Mediterranean vegetation emits a wide range of biogenic volatile organic compounds (BVOCs) among which isoprenoids present quantitatively the most important compound class. Here, we investigated the isoprenoid emission from two Mediterranean Cistaceae shrubs, Halimium halimifolium and Cistus ladanifer, under controlled and natural conditions, respectively. For the first time, diurnal emission patterns of the diterpene kaurene were detected in real-time by Proton-Transfer-Reaction-Timeof- Flight-Mass-Spectrometer. Kaurene emissions were strongly variable among H. halimifolium plants, ranging from 0.01 ± 0.003 to 0.06 ± 0.01 nmol m−2 s−1 in low and high emitting individuals, respectively. They were in the same order of magnitude as monoterpene (0.01 ± 0.01 to 0.11 ± 0.04 nmol m−2 s−1) and sesquiterpene (0.01 ± 0.01 to 0.52 nmol m−2 s−1) emission rates. Comparable range and variability was found for C. ladanifer under natural conditions. Labelling with 13C-pyruvate suggested that emitted kaurene was not derived from de novo biosynthesis. The high kaurene content in leaves, the weak relationship with ecophysiological parameters and the tendency of higher emissions with increasing temperatures in the field indicate an emission from storage pools. This study highlights significant emissions of kaurene from two Mediterranean shrub species, indicating that the release of diterpenes into the atmosphere should probably deserve more attention in the future