Gas exchange and low temperature resistance in two tropical high mountain tree species from the Venezuelan Andes

Cavieres, Lohengrin A.; Rada, Fermín; García-Núñez, Carlos; Cabrera, Hernán M.

doi:10.1016/s1146-609x(00)01077-8

Cited by 59 publications

(53 citation statements)

References 21 publications

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“…The P N of P. tarapacana was low and comparable to values measured in giant rosettes of Espeletia in the Venezuelan Andes, which ranged between 1.0-3.0 µmol m -2 s -1 for E. timotensis, E. spicata, and E. schultzii at 4 200 m (Goldstein et al 1989, Rada et al 1998. In the same manner, these low P N are comparable to those measured for Podocarpus oleifolius and Espeletia neriifolia (maximum rates between 1.9 and 2.2, respectively, at 3 200 m on a cloudy day), tree species that grow at the timberline in the Venezuelan Andes, in sites characterised by a low quantum input due to cloud cover most of the year (Meinzer et al 1984, Cavieres et al 2000. Relatively higher maximum P N (8-11 µmol m -2 s -1 ) were reported for freezing tolerant Afroalpine giant rosettes (Schulze et al 1985).…”

Section: Discussionsupporting

confidence: 53%

“…Carbon gain at high altitudes is constrained mainly by thermal restrictions due to low temperatures, low CO 2 partial pressures, and low water availability in arid Cor-dilleras, and in some cases there is a low radiation input (Tranquillini 1979, Körner 1998, Cavieres et al 2000. Nevertheless, remarkably positive photosynthetic rates are reported for different tree species at tree-line (Körner 1999).…”

Section: Discussionmentioning

confidence: 99%

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Leaf Gas Exchange and Water Relations in Polylepis tarapacana at Extreme Altitudes in the Bolivian Andes

et al. 2004

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Stress-induced restrictions to carbon balance, growth, and reproduction are the causes of tree-line formation at a global scale. We studied gas exchange and water relations of Polylepis tarapacana in the field, considering the possible effects of water stress limitations imposed on net photosynthetic rate (P N ). Daily courses of microclimatic variables, gas exchange, and leaf water potential were measured in both dry-cold and wet-warm seasons at an altitude of 4 300 m. Marked differences in environmental conditions between seasons resulted in differences for the dry-cold and wet-warm seasons in mean leaf water potentials (-1.67 and -1.02 MPa, respectively) and mean leaf conductances (33.5 and 58.9 mmol m -2 s -1 , respectively), while differences in mean P N (2.5 and 2.8 µmol m -2 s -1 , respectively) were not as evident. This may be related to limitations imposed by water deficit and lower photon flux densities during dry and wet seasons, respectively. Hence P. tarapacana has coupled its gas exchange characteristics to the extreme daily and seasonal variations in temperature and water availability of high elevations.

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Section: Discussionsupporting

confidence: 53%

Section: Discussionmentioning

confidence: 99%

Leaf Gas Exchange and Water Relations in Polylepis tarapacana at Extreme Altitudes in the Bolivian Andes

et al. 2004

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“…Temperature minima during our observations never dropped below (or even approached) temperatures causing 50% injury to leaves measured under laboratory conditions (Sklenář et al, 2010(Sklenář et al, , 2012). Because we did not observe frost injury in the field and have not found any reports of it in the literature, we infer that freezing resistance of the páramo plants is sufficient to protect them from recurrent night frosts, although the situation may be different in woody species from the tree-line ecotone (Cavieres et al, 2000). However, even without direct injury, frosts may affect plants due to the sensitivity of growth to low temperatures (Körner and Woodward, 1987).…”

Section: Discussionmentioning

confidence: 91%

Temperature Microclimates of Plants in a Tropical Alpine Environment: How Much does Growth Form Matter?

Sklenář

Kučerová

Macková

et al. 2016

Arctic, Antarctic, and Alpine Research

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“…paipana presenta un promedio de conductancia estomática (115.27 mmolH 2 O/m 2 .s) menor al que se ha medido en Espeletias típicas de los páramos venezolanos como E. schultzii (150 y 100 mmolH 2 O/m 2 .s) y E. neriifolia (200-250 mmolH 2 O/m 2 .s) (Cavieres, Rada, Azócar, García-Núñez, & Cabrera, 2000;Azócar & Rada, 2006). Para poblaciones de E. schultzii se ha demostrado que la Gs se reduce en un 34 % al ascender de 2 800 a 4 200 m (Rada, Azócar, González, & Briseño, 1998), mientras que con E. neriifolia se ha establecido que la asimilación neta de CO 2 durante días nublados se reduce a valores críticos, cercanos al punto de compensación (Cavieres, et al, 2000). Estas evidencias son solo una muestra de la complejidad de las respuestas funcionales de las rosetas suculentas frente a la variabilidad ambiental de alta montaña, aunque en general sugieren que las espeletias son plantas que apuestan a rendimientos fisiológicos bajos pero seguros, gracias a características morfoanatómicas de alta adaptación al páramo.…”

Section: Discussionunclassified

“…Por otra parte, en la depresión los individuos poseen hojas más grandes que en promedio mantienen una mayor temperatura, con valores cercanos a los óptimos para la fotosíntesis en E. neriifolia a 3 200 m (19.4 ºC, Cavieres, et al, 2000). Teniendo en cuenta que en Espeletias los óptimos fisiológicos se reducen a medida que se asciende en altitud (Cavieres, et al, 2000;Azocar & Rada, 2006), puede afirmarse que a 3 509 m y con una Tfol media de 18.3 ºC, E. paipana podría realizar una fotosíntesis óptima asociada a una alta Gs.…”

Section: Discussionunclassified

Pérdida de pubescencia foliar y sus efectos fisiológicos en Espeletia paipana (Asterales, Asteraceae), en el departamento de Boyacá-Colombia

Buitrago

Vanegas

Ramos

2015

RBT

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Pérdida de pubescencia foliar y sus efectos fisiológicos enAbstract: Loss of leaf pubescence and its physiological effects on Espeletia paipana (Asterales, Asteraceae), in the Boyacá-Colombia department. Espeletia paipana is an endangered giant caulescent rosette endemic to Boyacá department. In order to establish whether a plant disease, characterized by the loss of leaf pubescence (PPF) and attributed to the pathogenic action of endophytic microorganisms, is the cause of the increasing mortality of population, the physiological performance of the species was evaluated with and without PPF. The incidence (% leaves affected in each of the 27 individuals in the current population) and severity (% leaf area affected on 135 leaves) of the PPF were monitored over a period of nine months, in three topographic zones of different heights. During four consecutive days in both dry and wet season, physiological parameters as chlorophyll content index (ICC), stomatal conductance (Gs) and leaf temperature (Tfol) were measured in healthy and affected leaves. The study was complemented with isolations and pathogenicity tests to identify the causal agent of the PPF. Overall, although the disease incidence in E. paipana was constant over time, the severity progressed surpassing 60 % of the leaf area. The increasing of severity in the upper side of leaves was attributed to the photo-oxidative effect of high radiation between 11:00 h and 14:00 h of the day. The reduction of functional leaf area because of the PPF, led to low Gs with serious implications for carbon fixation and thus limiting growth and biomass renewal. The effect of season in Tfol varied according to the topographic zone, while the ICC did not present a defined pattern with respect to the PPF; its low values could be associated with the production of other pigments. Finally, although it is not possible to ensure that Botrytis sp. is the causative of the loss of leaf pubescence, it is postulated as the most probably causal agent due to its high representativeness in the isolates and its infectious potential during the pathogenicity tests. In general, the reduction of healthy leaf biomass and decrease of physiological performance suggest that PPF affect negatively the survival of E. paipana, which means that the use of biological controllers could be a strategy to mitigate its effect on the population. Rev. Biol. Trop. 63 (3): 845-858. Epub 2015 September 01.

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Gas exchange and low temperature resistance in two tropical high mountain tree species from the Venezuelan Andes

Cited by 59 publications

References 21 publications

Leaf Gas Exchange and Water Relations in Polylepis tarapacana at Extreme Altitudes in the Bolivian Andes

Leaf Gas Exchange and Water Relations in Polylepis tarapacana at Extreme Altitudes in the Bolivian Andes

Temperature Microclimates of Plants in a Tropical Alpine Environment: How Much does Growth Form Matter?

Pérdida de pubescencia foliar y sus efectos fisiológicos en Espeletia paipana (Asterales, Asteraceae), en el departamento de Boyacá-Colombia

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