Energy balance analysis of nighttime leaf temperatures and frost formation in a subalpine environment

Jordan, Dean N.; Smith, William K.

doi:10.1016/0168-1923(94)90020-5

Cited by 74 publications

(63 citation statements)

References 29 publications

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“…Consequently, they were poorly adapted to shedding surface moisture. Species in open habitats had a high susceptibility to leaf surface wetting throughout the growing season because radiationai cooling is important for driving leaf temperatures below air and dewpoint temperatures (Jordan & Smith 1994). As a result, leaves in open habitats had temperatures below dewpoint temperatures for long periods during any 24 h period and were frequently wet during morning hours.…”

Section: Correspondence Between Leaf Surface Characteristics and Suscmentioning

confidence: 99%

Patterns of leaf surface wetness for montane and subalpine plants

Brewer

Smith

1997

Plant Cell & Environment

168

148

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The frequency and duration of water on leaf surfaces have important consequences for plant growth and photosynthetic gas exchange. The objective of the present study was to compare the frequency and duration of leaf wetness under natural field conditions among species and to identify variation in structural features of leaves that may reduce surface wetness. During June-Septemher 1992 in the central Rocky Mountains (USA), natural leaf wetting due to rain and dewfall was observed on 79 of 89 nights in open meadow habitats compared to only 29 of 89 nights in the understorey. Dew formation occurred at relative humidities that were often well below 100% because of radiational heat exchange with cold night skies and low wind speeds (< 0-5 m s~*). A survey of 50 subalpine/montane species showed that structural characteristics associated with the occurrence and duration of leaf surface wetness differed among species and habitats. Both adaxial and abaxial surfaces accumulated moisture during rain and dewfall events. Leaf surfaces of open-meadow species were less wettable {P = 0-008), and had lower droplet retention (F = 0-015) and more stomata {P = 0-017) than adjacent understorey species. Also, leaf trichomes reduced the area of leaf surface covered by moisture. Ecophysiological importance is suggested by the high frequency of leaf wetting events in open microsites, influences on growth and gas exchange, and correspondence between leaf surface wettability and habitat.

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Section: Correspondence Between Leaf Surface Characteristics and Suscmentioning

confidence: 99%

Patterns of leaf surface wetness for montane and subalpine plants

Brewer

Smith

1997

Plant Cell & Environment

168

148

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“…However, aerodynamic decoupling also has a price during clear nights, when *Email: ch.koerner@unibas.ch ground vegetation undergoes stronger radiative cooling (down to 7 K below ambient) than do upright structures (e.g. Squeo et al 1991;Jordan and Smith 1994;Wesche et al 2008). In addition, small herbaceous growth forms have more developmental flexibility, shorter life cycles and shorter leaf life span and thus, can use shorter, climatically more favourable periods during the year than evergreen treeline trees.…”

Section: Introductionmentioning

confidence: 99%

Winter crop growth at low temperature may hold the answer for alpine treeline formation

Körner¹

2008

Plant Ecology & Diversity

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Background: Undisturbed high elevation treelines follow a common growing season isotherm, irrespective of latitude. Small stature plants thrive at much higher elevations because they grow in a favourable microclimate near the ground, whereas trees are aerodynamically coupled to free atmospheric circulation, hence the uniform treeline elevation in a given region. Aims: I argue that the treeline results from tree architecture and not from a tree-specific inferior physiology. At tissue level, all cold adapted higher plants (including winter crops) face similar temperature related limitations and are constrained by similar thermal thresholds. Methods: In order to explore this hypothesis, winter rape and winter oat were grown in the field and the daily rate of leaf expansion was measured during early winter, with temperatures similar to those at treeline at the beginning of the growing season (monthly mean temperature of 5 °C). Results: Leaves of these winter crops only grew when the degree hours above 5 °C for a given day exceeded zero. Rape and oats showed very similar responses. The data support a common temperature threshold for tissue formation in winter crops and treeline trees. Conclusions: A literature survey revealed lower temperature thresholds (close to freezing point) in arctic and Antarctic algae. It appears that the formation of complex, partly lignified tissue does not happen below 5 °C, whereas such temperatures exert little constraints on photosynthesis. The study illustrates that tissue growth in winter crops can help understand growth of treeline trees, given that both exhibit similar minimum temperature requirements for meristem functioning.

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“…• C below air temperature [10]. Thus, even in normal years, needles of P. canariensis seedlings may experience temperatures down to -13…”

Section: Discussionmentioning

confidence: 99%

“…The temperature range associated with frost damage (LT 10 -LT 100 ) differed significantly between needle ages. While currently expanding 10 ) and recorded at mean at 4.3…”

Section: Relationship Between Freezing Exotherms and Frost Damagementioning

confidence: 99%

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Ice nucleation and frost resistance of Pinus canariensis seedlings bearing needles in three different developmental states

et al. 2007

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-Frost resistance and ice formation in different developmental states of needles of P. canariensis seedlings were assessed. Regrowth after frost damage was used to determine the overall frost survival capacity. Two distinct freezing exotherms (E1, E2) were registered. E1 was between -1.7 and -2.0• C. Initial frost damage (LT 10 ) was 1.5-2.7• C below E1. E2 was between -5.6 and -6.0• C, and either corresponded with LT 50 or occurred in between LT 10 and LT 50 . Current year needles were less frost resistant than 1-year-old needles. The overall recuperation capacity of seedlings revealed that frost survival may be underestimated when only needle damage is assessed. Freezing of seedlings with or without roots had no effect on the frost resistance of needles but recuperation capacity was significantly affected. Seedlings survived -10• C during summer indicating that they withstand the lowest naturally occurring frosts in Tenerife. extracellular ice formation / freezing exotherm / Pinus canariensis / regrowth / subzero temperatures Résumé -Nucléation de glace et résistance au froid de semis de Pinus canariensis portant des aiguilles à trois différents stades de dévelop-pement. La résistance au froid et la formation de glace dans des aiguilles à différents stades de développement ont été déterminées chez des semis de Pinus canariensis. La repousse après les dommages du froid a été utilisée pour déterminer l'ensemble de la capacité de résistance au froid. Deux exothermes de congélation (E1, E2) ont été enregistrés. E1 était entre -1,7 et -2,0• C. Les premiers dommages du froid (LT 1 0) ont été constatés entre 1,5 et 2,7• C sous E1. E2 était entre -5,6 et -6,0• C et soit correspondait à LT 5 0 ou arrivait entre LT10 et LT50. Les aiguilles de l'année en cours ont été moins résistantes au froid que les aiguilles âgées de 1 an. La capacité de récupération globale des semis a révélé que la survie au froid pouvait être sous estimée quand on détermine seulement les dommages subis par les feuilles. La congélation des semis avec ou sans racines n'a pas eu d'effet sur la résistance au froid des aiguilles, mais la capacité de récupération a été significativement affectée. Les semis ont survécu à -10• C pendant l'été indiquant qu'ils étaient capables de résister aux basses températures qui se produisent à Ténérife. formation de glace extra cellulaire / exotherme de gel / Pinus canariensis / repousse / températures en dessous de zéro Abbreviations: LT 10 : Temperature at 10% frost damage ; LT 50 : Temperature at 50% frost damage ; LT 100 : Temperature at 100% frost damage ; E1: High temperature freezing exotherm ; E2: Low temperature freezing exotherm ; ΦPSII: Photochemical Efficiency of Photosystem II.

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Energy balance analysis of nighttime leaf temperatures and frost formation in a subalpine environment

Cited by 74 publications

References 29 publications

Patterns of leaf surface wetness for montane and subalpine plants

Patterns of leaf surface wetness for montane and subalpine plants

Winter crop growth at low temperature may hold the answer for alpine treeline formation

Ice nucleation and frost resistance of Pinus canariensis seedlings bearing needles in three different developmental states

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