Influence of radiation and drought on gas exchange of Austrocedrus chilensis seedlings

Gyenge, Javier; Fernández, María Elena; Schlichter, Tomás

doi:10.4067/s0717-92002007000300006

Cited by 24 publications

(42 citation statements)

References 21 publications

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“…Ser. et Bizarri, another native tree species of Patagonia (Gyenge et al 2007). Generally, increased WUE is observed with moderate stress, but as stress becomes severe, WUE decreases again (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…For example, the physiological responses of European species of the genus Quercus and Fagus are well known (Cochard et al 2000;Corcuera et al 2002;Lemoine et al 2002;Aranda et al 2004;Lendzion and Leuschner 2008), while the knowledge of the drought response of species in many other regions with Mediterranean-type climate, including northern Patagonia on the western rim of South America, is limited to just a few species (Suarez et al 2004;Gyenge et al 2007;Martinez Pastur et al 2007;Piper et al 2007;Peri et al 2009), or even non-existent for other important forest species.…”

Section: Introductionmentioning

confidence: 98%

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Seedling drought stress susceptibility in two deciduous Nothofagus species of NW Patagonia

Varela

Gyenge

Fernández

et al. 2010

Trees

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The physiological capacities of seedlings to cope with drought may be subject to strong selective pressure in the context of future climate scenarios, threatening the regeneration and sustainability of forests. Characterization of the responses and the variability between species is of interest to breeding and domestication programs. In this study, our main goal was to describe some of the physiological mechanisms involved in the drought response of Nothofagus nervosa and N. obliqua, two forest species of ecological and commercial importance (high wood quality) in NW Patagonia. We tested for differences in water status, gas exchange and survival in response to a gradually imposed severe drought. Based on cavitation vulnerability curves and hydraulic conductivity measurements, we can conclude that N. obliqua stems have higher specific hydraulic conductivity and somewhat lower vulnerability to cavitation than N. nervosa stems, leading it to sustain higher stomatal conductance under non-severe drought conditions. N. obliqua had higher photosynthetic capacity than N. nervosa, due both to characteristics of its hydraulic architecture and to its higher metabolic capacity.Our results indicate that both species present characteristics of plants susceptible to water stress. Also, both species showed behavior resembling an anisohydric response. This behavior results from a lack of stomatal control over transpiration while the soil dehydrates, probably accompanied by very high vulnerability to cavitation. In contrast, both species had similar high stomatal sensitivity to vapor pressure deficit when soil water was limiting.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Seedling drought stress susceptibility in two deciduous Nothofagus species of NW Patagonia

Varela

Gyenge

Fernández

et al. 2010

Trees

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“…In forest ecosystems with high luminosity, direct sunlight during many hours reach different points of the understory, and may generate photo-inhibition in plants adapted to low radiation such as ciprés (Pearcy, 1990). Ciprés is a shade-tolerant specie (Gyenge et al, 2007), whose transpiration rate is restricted through stomatal closure, so the capacity of cooling is limited and therefore susceptible to heat stress (Gyenge et al, 2007). For this reason, in their first years as seedlings, ciprés grows better under the protection of a nurse plant (Gobbi, 2007).…”

Section: Seedling Survival and Growthmentioning

confidence: 99%

Micro-environmental changes induced by shape and size of forest openings: effects on Austrocedrus chilensis and Nothofagus dombeyi seedlings performance in a Pinus contorta plantation of Patagonia, Argentina

2016

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Aim of the study: to analyze, within a Pinus contorta plantation, the effects of artificially created small rectangular and small medium circular canopy gaps on: i) photosynthetic active radiation (PAR), and soil temperature and moisture, and ii) survival and growth of planted Austrocedrus chilensis and Nothofagus dombeyi seedlings, species which formerly composed the natural forest of the area.Study area: A 2 ha stand of a Pinus contorta stand in Los Alerces National Park, Argentina (42°43'S, 71°43'W, 490 m.a.s.l.). Material and methods:The Pinus contorta stand was 25 yr old, 22 m height and 26 cm DBH, presenting 1000 trees ha -1 of density and 53 m 2 ha -1 of basal area. In 2009, rectangular and circular gaps were created within the stand and then seedlings were planted. During two growing seasons (2010-2011 and 2011-2012), PAR, soil temperature and moisture were measured in gaps and understory (control), and seedling survival and growth in gaps.Main results: During both seasons, soil temperature did not differ among gaps and control, whereas PAR and soil moisture were lower in control than in gaps. Seedling survival was high in all gaps regardless of species and season. Seedlings showed higher diameter growth in rectangular than in circular gaps.Research highlights: Austrocedrus chilensis and N. dombeyi seedlings survival is high and their growth slightly affected, when planted in differently-sized canopy gaps within a Pinus contorta plantation in Patagonia. However, other gap sizes and stand densities should be tested before recommending which one shows better results for reconverting monocultures into former native forests.

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“…This feature is a guarantee of drought stress each summer. However, to have a better understanding of the stressful conditions during the trial, rain pulses were registered and vapor pressure deficit (VPD) was estimated with local climate data, considering that, at the species level, 2.5 kPa is the threshold beyond which Patagonian Cypress closes its stomata even when water soil content is not limiting (Gyenge et al, 2007).…”

Section: Stressful Conditionsmentioning

confidence: 99%

“…Gyenge et al (2005Gyenge et al ( , 2007Gyenge et al ( , 2008 have shown that it presents several features typical of water-spending species, such as high vulnerability to xylem cavitation and high cell water content at turgor loss point. However, they also observed that the species compensates for those vulnerabilities by means of rapid stomatal response, since even when the soil water content is not limiting, just a moderate evaporative demand (vapor pressure deficit ≈ 2.5 kPa) is enough for the species to close its stomata, thus preventing water potential to Genetic variation of Patagonian Cypress in Δ 13 C an opposite result).…”

Section: Introductionmentioning

confidence: 99%

Genetic variation in seedling water-use efficiency of Patagonian Cypress populations from contrasting precipitation regimes assessed through carbon isotope discrimination

et al. 2012

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Water-use efficiency (WUE) is a physiological parameter that plays a significant role in the evolutionary dynamics of many forest tree species. It can be estimated indirectly through carbon isotope discrimination (Δ). In general, plants of more arid origins have lower values of Δ. In order to study the degree of genetic control of this parameter and the genetic variation in Δ of Patagonian Cypress seedlings, three Argentinean natural populations chosen to represent two contrasting precipitation regimes were sampled in a common garden trial. The dry situation was represented by two neighboring marginal forest patches from the steppe, while the humid condition was represented by a population with 1,200 mm higher mean annual precipitation. Height (H) and Δ were measured in 246 five-year-old seedlings from 41 open-pollinated families. The factor 'family' had a significant effect on both variables; however heritability for Δ was found not to be significant in two out of the three populations. This could be explained by low sample size in one of them and by a real evolutionary effect in the other. An inverse association between H and Δ was verified, which is interpreted as evidence of an adaptation process at the intra-population level. The studied populations were not shown to discriminate carbon isotopes differently; hence evidence of adaptation to current environmental conditions could not be obtained. On the other hand, the arid populations proved to be quite different in terms of genetic variation, which seems to be the consequence of genetic drift and isolation.Key words: Austrocedrus chilensis; differentiation; adaptation; genetic drift. ResumenVariación genética de poblaciones naturales de Ciprés de la Cordillera con regímenes de precipitación contrastados, en la eficiencia del uso del agua de plántulas, a través de la discriminación isotópica del carbono La eficiencia en el uso del agua es un parámetro fisiológico que desempeña un rol significativo en la dinámica evolutiva de muchas especies forestales. Puede estimarse indirectamente a través de la discriminación isotópica del carbono (Δ). En general, las plantas de orígenes más áridos tienen valores de Δ más bajos. Con el propósito de estudiar el grado de control genético de Δ y la variación genética en este parámetro en plántulas de Ciprés de la Cordillera, tres poblaciones naturales elegidas para representar dos regímenes de precipitación contrastados fueron muestreadas en un ensayo de ambiente común. La condición árida estuvo representada por dos fragmentos de bosque esteparios marginales, vecinos entre sí, mientras que la condición húmeda fue representada por una población con una precipitación media anual 1.200 mm superior a la de las áridas. Se midió altura total (H) y Δ en 246 plántulas de 5 años de edad correspondientes a 41 familias de polinización abierta. El factor 'familia' tuvo un efecto significativo en ambas variables; sin embargo, la heredabilidad para Δ no resultó significativa en dos de las tres poblaciones. En una de ellas esto pod...

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Influence of radiation and drought on gas exchange of Austrocedrus chilensis seedlings

Cited by 24 publications

References 21 publications

Seedling drought stress susceptibility in two deciduous Nothofagus species of NW Patagonia

Seedling drought stress susceptibility in two deciduous Nothofagus species of NW Patagonia

Micro-environmental changes induced by shape and size of forest openings: effects on Austrocedrus chilensis and Nothofagus dombeyi seedlings performance in a Pinus contorta plantation of Patagonia, Argentina

Genetic variation in seedling water-use efficiency of Patagonian Cypress populations from contrasting precipitation regimes assessed through carbon isotope discrimination

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