Effect of Powdery Mildew on Net Photosynthesis, Dark Respiration, and Kernel Composition of Pecan

Plant Disease ◽  
1984 ◽  
Vol 68 (6) ◽  
pp. 519
Author(s):  
T. R. Gottwald
Keyword(s):  
Powdery Mildew ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Kernel Composition

Two physiological races of Tsuga canadensis in Wisconsin

1975 ◽  
Vol 53 (9) ◽  
pp. 940-951 ◽  
Author(s):  
William Eickmeier ◽  
Michael Adams ◽  
Donald Lester
Keyword(s):  
Dark Respiration ◽  
Net Photosynthesis ◽  
Tsuga Canadensis ◽  
Seedling Morphology ◽  
Seed Sources ◽  
Temperature Regimes ◽  
Disjunct Populations ◽  
Use Efficiency ◽  
Osmotic Potentials ◽  
Carbon Dioxide Balance

Population differentiation in Tsuga canadensis (L.) Carr. from Wisconsin was tested by comparing seedlings grown from seed collected within the present range in the northeast and from seed collected in disjunct populations southwest of the present range. The seedlings, established in hydroponic culture, were subjected to two preconditioning temperature regimes and two water stress simulations. Net photosynthesis, dark respiration, and transpiration capacities were measured and internal leaf resistances were calculated.The southwestern Wisconsin population had a more favorable carbon dioxide balance at warmer tissue temperatures, particularly at low irradiance levels, and at higher osmotic potentials, than did the northeastern population, which was better adapted to lower tissue temperatures and lower osmotic potentials. Additional differences between seed sources in seedling morphology, transpiration rate, and water-use efficiency were found. These differences in morphology and physiological responses corresponded to the macroclimates in which these populations were found, southwestern Wisconsin being warmer and drier than the northeastern part of the state.

Productivity of Vegetable Crops in a Region of High Solar Input. III. Carbon Balance of Potato Crops

1974 ◽  
Vol 1 (2) ◽  
pp. 283 ◽  
Author(s):  
PJM Sale
Keyword(s):  
Carbon Balance ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Gas Analysis ◽  
Co2 Uptake ◽  
Co2 Efflux ◽  
Vegetable Crops ◽  
Weight Changes ◽  
Potato Crops

The carbon balance of potato crops has been studied by measuring canopy net photosynthesis and dark respiration losses with a field assimilation chamber and semi-closed gas analysis system. Results are given for the latter part of growth in both a spring-planted and a summer-planted crop. Net CO2 uptake increased with solar input to reach 35–40mg dm-2 (ground area) h-1 at 400–450 W m-2, but light saturation then occurred and little or no further uptake resulted from increases in solar input up to 1000 W m-2. This supports the previous conclusion that net photosynthesis in the potato is determined by the size of the 'sink' provided by the developing tubers. The imposed experimental variables of reduced solar input (21 and 34% shade) and soil moisture were found not to affect the relation between solar input and CO2 uptake, and the effect of chamber temperature was also very small. Dark respiration rates of the canopy were markedly sensitive to temperature, and also to the solar input prior to measurement. Respiration from the below-ground plant parts accounted for a considerable part of the total plant respiration. In all, 15–20 % of the net assimilation during daylight hours was lost by night respiration. There was little variation in CO2 efflux from uncropped soil during the experiments. Dry weight changes calculated from the gasometric measurements were in accordance with those found from previous growth analysis. * Part II, Aust. J. Agric. Res., 1973, 24, 751–62.

Response of Gas Exchange in Jointed Goatgrass (Aegilops cylindrica) to Environmental Conditions

Weed Science ◽  
1989 ◽  
Vol 37 (4) ◽  
pp. 562-569 ◽  
Author(s):  
David R. Gealy
Keyword(s):  
Soil Moisture ◽  
Gas Exchange ◽  
Environmental Conditions ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Soil Matric Potential ◽  
Dark Respiration Rate ◽  
Matric Potential ◽  
Aegilops Cylindrica ◽  
Jointed Goatgrass

Gas exchange of jointed goatgrass leaves was affected by temperature, irradiance level, and soil matric potential. Net photosynthesis of leaves under saturating irradiance (PPFD3= 1850 (μE·m–2·s−1) was optimum at about 20 C. At 25 C, net photosynthesis was nearly 90% of maximum at a PPFD of 800 μE·m–2·−1. Transpiration, and presumably water use, increased steadily with temperature from 10 to 40 C. Dark respiration rate and compensation points for light and for CO2increased exponentially, or nearly so, from 10 to 40 C. Soil moisture deficits of −130 kPa reduced net photosynthesis and transpiration by about 30 and 55%, respectively, compared to well-watered plants.

scholarly journals Net Photosynthesis and Dark Respiration of Pear Leaves Infected by Japanese Pear Rust

1990 ◽  
Vol 59 (1) ◽  
pp. 99-105 ◽  
Author(s):  
Hitoshi HONJO ◽  
Kazuo KOTOBUKI ◽  
Toshikazu ASAKURA ◽  
Fukuya KAMOTA
Keyword(s):  
Dark Respiration ◽  
Net Photosynthesis ◽  
Japanese Pear

The morphological basis of variation in net photosynthetic and respiratory responses of the mat-forming lichen species Stereocaulon virgatum and S. tomentosum

1989 ◽  
Vol 67 (1) ◽  
pp. 167-176 ◽  
Author(s):  
D. S. Coxson ◽  
J. Lancaster
Keyword(s):  
Water Vapor ◽  
Dark Respiration ◽  
Cloud Forest ◽  
A Priori ◽  
Net Photosynthesis ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Response Curves ◽  
Morphological Variations ◽  
Closed Canopy

Response patterns of net photosynthesis and dark respiration are examined in two species of Stereocaulon: S. tomentosum Fr., from early successional pine forest communities of the southern Canadian Rockies, and S. virgatum Ach., an early colonizer in tropical cloud-forest environments. These responses, measured in both intact and dissected mat segments, are described in the context of the influence of morphological variations on patterns of water vapor transport. Saturation response curves are fitted to data, allowing description of maximal rates of both net photosynthesis and dark respiration, water contents at which rates are half maximal, maximal water efficiency, and moisture compensation points. In S. tomentosum the closed-canopy nature of the lichen mat profile results in the development of a distinct shade ecotype in lower thallus segments. This canopy profile also impedes water vapor transport from within the mat profile, creating a more mesic microclimate for photobionts located at depth within the lichen mat. This stands in contrast to the open upper canopy profile of S. virgatum, which allows greater convective exchange at depth and appears to preclude the development of distinct sun–shade photobiont ecotypes. Net photosynthetic activity remains high in fully saturated thalli of S. tomentosum, yet in S. virgatum it is depressed by over 50% at full thallus saturation. This greater depression of photosynthetic uptake at full thallus saturation in the species of the more mesic environment contradicts a priori assumptions based on previous concepts of xeric–mesic response gradients in lichens. These responses are discussed in context of other selective pressures influencing lichen mat morphology.

Influence of temperature on net CO2 exchange in roses

1991 ◽  
Vol 71 (1) ◽  
pp. 235-243 ◽  
Author(s):  
J. Jiao ◽  
M. J. Tsujita ◽  
B. Grodzinski
Keyword(s):  
Dark Respiration ◽  
Net Photosynthesis ◽  
Co2 Exchange ◽  
Effect Of Temperature ◽  
Flower Bud ◽  
Temperature Range ◽  
Whole Plant ◽  
Optimal Temperature Range ◽  
Influence Of Temperature On ◽  
Whole Plants

The effect of temperature on net CO2 exchange of source and sink tissues of the flowering shoots and of whole plants was examined using single-stemmed Samantha roses. At all stages of shoot development, the optimal temperature range for whole-plant carbon (C) gain at saturating irradiance and ambient CO2 level was between 20° and 25 °C, narrower than the temperature range for optimal leaf net photosynthesis. Dark respiration increased more dramatically than photosynthesis with temperatures between 15 and 35 °C. At 25 °C, C loss due to respiration from the flower bud at colour bud stage accounted for 45% of the C loss of the flowering shoot. At low irradiance levels (e.g. 200 μmol m−2 s−1) whole-plant net photosynthesis was greater at 16° than at 22 °C because of a greater reduction in respiration. Lowering the night temperature from 27 to 17 °C also increased daily C gain due to a reduction in the C lost at night. Whole-plant net photosynthesis of plants grown and measured at enriched (1000 ± 100 μL L−1) CO2 was greater than that of plants grown and measured at ambient (350 ± 50 μL L−1) level at temperatures between 15° and 35 °C. Furthermore, the optimal temperatures for whole-plant net photosynthesis in CO2 enrichment was higher than at ambient CO2 level. Key words: Dark respiration, net photosynthesis, Rosa hybrida, temperature

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