Ecophysiology of Two Solar-Tracking Desert Winter Annuals. I. Photosynthetic Acclimation to Growth Temperature

1982 ◽  
Vol 9 (3) ◽  
pp. 321 ◽  
Author(s):  
IN Forseth ◽  
JR Ehleringer
Keyword(s):  
High Temperatures ◽  
Meteorological Conditions ◽  
Death Valley ◽  
Photosynthetic Acclimation ◽  
Plant Life ◽  
Solar Tracking ◽  
Thermal Death ◽  
Winter Annuals ◽  
Growth Chambers ◽  
Temperature Optima

The ability of two solar-tracking desert winter annuals, Lupinus arizonicus Watson and Malvastrum rotundifolium Gray, to acclimate their photosynthetic characteristics to different growth temperatures was examined. Plants were grown in growth chambers under 25/15°C and 40/30°C thermal regimes. The plants grown at 40/30°C were also subjected to a drying cycle in order to assess whether or not drought affected the photosynthetic acclimation to high temperatures. Both species exhibited shifts in their temperature optima and thermal death points for photosynthesis. The droughted plants showed no further acclimation than did the watered plants grown at 40/30°C. Using representative meteorological conditions measured in Death Valley, California, it was predicted that photosynthetic acclimation plays only a small role in enhancing daily carbon-gaining ability for late-season conditions. However, under conditions of drought stress and high temperatures, the acclimation may prevent thermal death and extend plant life.

Reproductive Responses of Capsicum annuum to High Temperatures

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 543c-543
Author(s):  
Ami N. Erickson ◽  
Albert H. Markhart
Keyword(s):  
Capsicum Annuum ◽  
High Temperatures ◽  
Fruit Development ◽  
Flower Development ◽  
Fruit Set ◽  
Fruit Production ◽  
Yield Reduction ◽  
Bud Size ◽  
Growth Chambers ◽  
Constant Growth

Fruit yield reduction due to high temperatures has been widely observed in Solanaceous crops. Our past experiments have demonstrated that Capsicum annuum cultivars Ace and Bell Boy completely fail to produce fruit when grown at constant 33 °C. However, flowers are produced, continually. To determine which stages of flower development are sensitive to high temperatures, pepper buds, ranging in size from 1 mm to anthesis, were exposed to high temperatures for 6 hr, 48 hr, 5 days, or for the duration of the experiment. Fruit set for each bud size was determined. Exposure to high temperatures at anthesis and at the 2-mm size stage for 2 or more days significantly reduced fruit production. To determine whether inhibition of pollination, inhibition of fertilization, and/or injury to the female or male structures prevents fruit production at high temperatures, flowers from pepper cultivars Ace and Bell Boy were grown until flowers on the 8th or 9th node were 11 mm in length. Plants were divided between 25 °C and 33 °C constant growth chambers for 2 to 4 days until anthesis. At anthesis, flowers from both treatments were cross-pollinated in all combination, and crosses were equally divided between 33 or 25 °C growth chambers until fruit set or flowers abscised. All flower crosses resulted in 80% to 100% fruit set when post-pollination temperatures were 25 °C. However, post-pollination temperatures of 33 °C significantly reduced fruit production. Reduced fruit set by flowers exposed to high temperatures during anthesis and pollination is not a result of inviable pollen or ovule, but an inhibition of fertilization or initial fruit development.

Photosynthetic Adaptation to High Temperatures: A Field Study in Death Valley, California

Science ◽  
1972 ◽  
Vol 175 (4023) ◽  
pp. 786-789 ◽  
Author(s):  
O. Bjorkman ◽  
R. W. Pearcy ◽  
A. T. Harrison ◽  
H. Mooney
Keyword(s):  
Field Study ◽  
High Temperatures ◽  
Death Valley ◽  
Photosynthetic Adaptation

scholarly journals Meteorological Conditions at Racetrack Playa, Death Valley National Park: Implications for Rock Production and Transport

2011 ◽  
Vol 50 (12) ◽  
pp. 2361-2375 ◽  
Author(s):  
Ralph D. Lorenz ◽  
Brian K. Jackson ◽  
Jason W. Barnes ◽  
Joseph N. Spitale ◽  
Jani Radebaugh ◽  
...  
Keyword(s):  
National Park ◽  
Probability Distributions ◽  
Meteorological Data ◽  
Time Lapse ◽  
Meteorological Conditions ◽  
Death Valley ◽  
Trail Formation ◽  
Strong Winds ◽  
Death Valley National Park

AbstractThree decades of weather records at meteorological stations near Death Valley National Park are analyzed in an attempt to gauge the frequency of conditions that might form and erase the famous trails of wind-blown rocks in the mud of Racetrack Playa. Trail formation requires the playa to be wet, followed by strong winds and/or freezing conditions. Weather records are compared with a limited set of meteorological data that were acquired in situ at the playa over three winters and that indicate freezing on 50, 29, and 15 nights during the winters of 2007/08–09/10, respectively, as well as with the hydrological condition of the playa as determined by time-lapse cameras that observed flooding over ~1, ~5, and ~40 days, respectively, during those winters. Measurements at the nearby Panamint and Hunter Mountain stations are found to be a useful, if imperfect (~50%), indicator of Racetrack Playa conditions and give some features of Racetrack Playa’s micrometeorological behavior. Wind speed probability distributions suggest that winds that are fast enough to cause unassisted rock motion are rare and therefore that freezing of water on the playa has a role in a significant fraction of movement events.

scholarly journals EARLY TEMPERATURES INFLUENCE BROCCOLI GROWTH AND HEAD QUALITY

HortScience ◽  
1990 ◽  
Vol 25 (8) ◽  
pp. 865C-865
Author(s):  
A. R. Jones ◽  
D. C. Sanders ◽  
R. J. Dufault
Keyword(s):  
Plant Growth ◽  
Brassica Oleracea ◽  
High Temperatures ◽  
Development Stage ◽  
Head Development ◽  
Tolerant Plant ◽  
Growth Chambers ◽  
Heat Tolerant

Three broccoli (Brassica oleracea L. Italica group) cultivars (Baccus, Packman, and Southern Comet) were grown for 14, 24, or 34 days at 22/18C (day/night) in a greenhouse. Then plants were moved to growth chambers where temperatures were maintained at 26/22, 30/26, or 34/30C and were grown for 1, 2, or 3 weeks before returning them to the greenhouse. A1 varieties when exposed to high temperatures developed smaller heads Packman when exposed to high temperatures resulted in a reduction in uniformity. Other cultivars were not effected. Lack of openness, an important marketable characteristic was reduced by high temperatures. However, Baccus at 34 days old was not effected by the heat. We would expect this response since this is the head development stage and cultivar is heat tolerant. Plant exposed to high temperatures developed heads earlier when held for 3 weeks. When plants were held at 36/30C for 3 weeks, the largest reduction in plant growth was recorded. However, all plants showed a reduction in growth when exposed to high temperatures.

Ecophysiology of two solar tracking desert winter annuals

Oecologia ◽  
1983 ◽  
Vol 57 (3) ◽  
pp. 344-351 ◽  
Author(s):  
I. N. Forseth ◽  
J. R. Ehleringer
Keyword(s):  
Solar Tracking ◽  
Winter Annuals

scholarly journals The Influence of Starvation on the Thermal Death-Point on Insects

1934 ◽  
Vol 11 (1) ◽  
pp. 48-53
Author(s):  
MELLANBY KENNETH
Keyword(s):  
High Temperatures ◽  
Moist Air ◽  
Dry Air ◽  
Pediculus Humanus ◽  
Thermal Death ◽  
Thermal Death Point ◽  
Food Reserves

Experiments are described in which newly hatched larval lice (Pediculus humanus corporis) and adult C. fatigans were exposed to high temperatures. The humidity was controlled, and the exposures lasted for either 1 or 24 hours. Larval lice, whether fed or unfed, withstood 46.5° C. for 1 hour, while the Culex were much less resistant--they only withstood a temperature of 39° C. The humidity of the air did not affect these results. When exposed for 24 hours, larval lice which had fed withstood 38° C. in moist air. They only withstood 33° C. in dry air, as they were killed by desiccation at higher temperatures. Mosquitoes (C. fatigans) which had gorged gave similar results. They survived 37° C. for 24 hours in moist air, and only 32° C. in dry. Unfed lice or mosquitoes behaved differently, as they could not withstand such high temperatures for periods of 24 hours. This was because they had small food reserves, and at high temperatures their rate of metabolism was so increased that they died of starvation.

scholarly journals 195 PHYSIOLOGICAL STUDY OF HEAT TOLERANCE IN RHODODENDRON SPP.

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 457b-457
Author(s):  
Thomas G. Ranney ◽  
Frank A. Blazich ◽  
Stewart L. Warren
Keyword(s):  
High Temperatures ◽  
Heat Tolerance ◽  
Temperature Sensitivity ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Physiological Study ◽  
Temperature Optima ◽  
Two Populations

Temperature sensitivity of net photosynthesis (Pn) was evaluated among 4 taxa of rhododendron including Rhododendron hyperythrum, R. russatum, and plants from two populations (northern and southern provenances) of R. catawbiense. Measurements were conducted on individual leaves at temperatures ranging from 15 to 40C. Temperature optima for Pn ranged from a low of ∼21 C for R. russatum to a high of ∼27C for R. hyperythrum. At 40C, Pn rates for R. hyperythrum, R. catawbiense (northern provenance), R. catawbiense (southern provenance), and R. russatum were 7.8, 5.7, 3.5, and 0.2 μmol·m-2·s-1, respectively. R. catawbiense from the southern provenance did not appear to have greater heat tolerance than plants from the northern provenance. There was no difference in temperature sensitivity of dark respiration among the taxa. Variations in heat tolerance among species appeared to result from a combination of stomatal and nonstomatal limitations on Pn at high temperatures.

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