Summary
A comparison of photosynthetic adaptations of desert ephemerals from sun and shade environments has shown differences in the magnitude and timing of maximum CO2 assimilation. Photosynthetic rates of species from the sun environment were significantly higher, and maximum observed levels occurred both earlier in the day and earlier in the growing season. For plants of both sites the CO2 assimilation rates were relatively low when the soil water content was highest in the winter months. Anatomical modifications of specific leaf weight occurred for species of both environments, but were not correlated with improved water use efficiency. Throughout the growing season the stomatal conductance of most species was higher than 0.30 cm/s and effects a maximization of photosynthesis when water is available, at the expense of water use efficiency.
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References
Armond PA, Mooney HA (1978) Correlation of photosynthetic unit size and density with photosynthetic capacity. Carnegie Inst Wash Yb 77:234–237
Beatley JS (1967) Survival of winter annuals in the northern Mojave Desert. Ecology 48:745–750
Chabot BF, Jurik TW, Chabot JF (1979) Influence of instantaneous and integrated light-influx density ofleaf anatomy and photosynthesis. Amer J Bot 66:940–945
Clough JM, Alberte RS, Teeri JA (1979) Photosynthetic adaptation of Solanum dulcamara L. to sun and shade environments. II. Physiological characterization of phenotypic response to environment. Plant Physiol 64:25–30
Forseth I, Ehleringer JR (1980) Solar tracking response to drought in a desert annual. Oecologia (Berl) 44:159–163
Johnson HB, Rowlands PG, Ting IP (1979) Tritium and carbon-14 double isotope porometer for simultaneous measurements of transpiration and photosynthesis. Photosynthetica 13:409–418
Jurik TW, Chabot JF, Chabot BF (1979) Ontogeny of photosynthetic performance in Fragaria virginiana under changing light regimes. Plant Physiol 63:542–547
Monson RK, Szarek SR (1979) Ecophysiological studies of Sonoran Desert plants. V. Photosynthetic adaptations of Machaeranthera gracilis, a winter annual. Oecologia (Berl) 41:317–327
Mooney HA, Ehleringer JR (1978) The carbon gain benefits of solar tracking in a desert annual. Plant, Cell & Environ. 1:307–311
Mooney HA, Ehleringer J, Berry JA (1976) High photosynthetic capacity of a winter annual in Death Valley. Science 194:322–324
Mulroy TW, Rundel PW (1977) Annual plants: adaptations to desert environments. Bioscience 27:109–114
Nobel PS (1976) Photosynthetic rates of sun vs. shade leaves of Hyptis emoryi. Plant Physiol 58:218–223
Nobel PS (1977) Internal leaf area and cellular CO2 resistance: photosynthetic implications of variations with growth conditions and plant species. Physiologia Plant 40:137–144
Patten DT (1978) Productivity and production efficiency of an upper Sonoran Desert ephemeral community. Amer J Bot 65:891–985
Smith WK, Nobel PS (1977) Influences of seasonal changes in leaf morphology on water-use efficiency for three desert broadleaf shrubs. Ecology 58:1033–1043
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Wallace, C.S., Szarek, S.R. Ecophysiological studies of Sonoran Desert plants. VII. Photosynthetic gas exchange of winter ephemerals from sun and shade environments. Oecologia 51, 57–61 (1981). https://doi.org/10.1007/BF00344653
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DOI: https://doi.org/10.1007/BF00344653