An Ecologial Significance of Seasonal Leaf Variability in a Desert Shrub

Cunningham, Gary L.; Strain, Boyd R.

doi:10.2307/1933890

Cited by 89 publications

(45 citation statements)

References 11 publications

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“…A few desert perennials remain photosynthetically active throughout a wide range of environmental temperatures and are capable of rapidly responding to precipitation (1,6,10). Others are photosynthetically inactive during some portion of the year and become active during periods of low water stress at moderate air temperatures (5,8,11) or high air temperature (4). We report here the results of a field study with a desert cactus, indicating not only the persistence of photosynthetic activity during periods of drought, but a dramatic, rapid shift in the level of metabolic activity in response to precipitation.…”

mentioning

confidence: 78%

Drought Adaptation in Opuntia basilaris

Szarek¹,

Johnson²,

Ting³

1973

Plant Physiol.

146

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Contrasting metabolic regimes operate in Opuntia basilaris Engelm. and Bigelov, before and after precipitation. During periods of drought, atmospheric CO2 exchange and transpiration are greatly reduced throughout the day/night cycle by stomatal closure and a highly impervious cuticle. The hypothesis is that endogenously produced C02 is retained and recycled through dark CO2 fixation, organic acid transformations, photosynthesis, and respiration. Immediately following precipitation, nighttime stomatal opening is initiated, permitting increased atmospheric C02 assimilation and organic acid synthesis.

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confidence: 78%

Drought Adaptation in Opuntia basilaris

Szarek¹,

Johnson²,

Ting³

1973

Plant Physiol.

146

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“…The amount of leaf pubescence was measured by carefuIly shaving the leaves on both surfaces, then drying and weighing the hairs. Density thickness (dry weight per unit surface of leaves; Cunningham and Strain, 1969) was measured periodically on both species, taking disks of known area with a cork borer.…”

Section: Methodsmentioning

confidence: 99%

Morphological and physiological correlates of niche breadth in two species of Espeletia (Compositae) in the Venezuelan Andes

Baruch

Smith

1979

Oecologia

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We compared adaptive strategies in two plants of Venezuelan páramos (alpine areas): the widely distributed, caulescent, and pubescent Espeletia schultzii Wedd. with the acaulescent, nearly glabrous E. atropurpurea A.C. Smith which is restricted to mesic sites just above treeline. Both species occur together at 3,450 m, near treeline.Physiologically, E. schultzii was more drought resistant than E. atropurpurea, and was better adapted for carbon dioxide fixation under low temperatures. The densely pubescent leaves of E. schultzii are highly reflective; this increases the intensity of light needed for photosynthetic saturation and influences leaf temperature. Leaf pubescence may reduce the level of insect predation.Measurements of leaf productivity indicate higher values for E. atropurpurea during the rainy season and higher values for E. schultzii during the dry season. However, annual values of leaf productivity are similar for both species.Benefits of specialization in E. atropurpurea include reduced costs for stem and leaf hair production, higher growth rates during the rainy season and the ability to grow beneath canopies of some larger arborescent species. Costs of specialization include lower growth rates during the dry season, great susceptibility to insect predation and restriction to low elevation, mesic sites.

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“…4), and specific leaf weight. These structural changes may influence P N through the physical component of rM, or, alternatively, they may simply parallel changes in some other factor such as photosynthetic enzyme activity which determines r M and P N. The latter seems more likely because when Siratro and green panic grown at the highest illuminance are compared and in other instances (Pearce, Brown, and Blaser 1968;Cunningham, and Strain 1969), there is a negative correlation between leaf thickness, specific leaf weight, andPN .…”

Section: **mentioning

confidence: 99%

Photosynthesis of Tropical Pasture Plants II. Temperature and Illuminance History

Ludlow¹,

Wilson²

1971

Aust. Jnl. Of Bio. Sci.

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Grasses and legumes were grown at two temperatures in controlled-environment rooms and at three illuminances (obtained by shading) in a glasshouse. Carbon dioxide and water vapour exchange of leaves were measured in an open gas analysis system.Net photosynthetic rates of grasses and legumes grown at 20°C and measured at 30°C were lower (and transfer resistances were concomitantly higher) than values for plants grown at 30°C, but almost complete acclimatization to the higher temperature occurred within 15 hr. Dark respiration rates varied with species and with illuminance prior to measurement, but were unaffected by growth temperature.Shading markedly affected the anatomy and the photosynthetic characteristics of both grass and legume leaves. Shaded leaves were thinner and contained fewer, smaller, and less densely packed cells than unshaded leaves. Light saturation point, light compensation point, and dark respiration rate declined as the level of shading increased, but the initial slope of the light response curve was unaffected. The lower net photosynthetic rate of shaded leaves was associated with increased stomatal and mesophyll resistances, and it is argued that the latter arose from higher carboxylation resistances. Net photosynthetic rate was positively related to leaf thickness, specific leaf weight, and the reciprocal of mesophyll resistance. These relationships and the relationship between net photosynthesis and chlorophyll content are discussed.

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An Ecologial Significance of Seasonal Leaf Variability in a Desert Shrub

Cited by 89 publications

References 11 publications

Drought Adaptation in Opuntia basilaris

Drought Adaptation in Opuntia basilaris

Morphological and physiological correlates of niche breadth in two species of Espeletia (Compositae) in the Venezuelan Andes

Photosynthesis of Tropical Pasture Plants II. Temperature and Illuminance History

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