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.

scholarly journals Heat Tolerance of Selected Species and Populations of Rhododendron

1995 ◽  
Vol 120 (3) ◽  
pp. 423-428 ◽  
Author(s):  
Thomas G. Ranney ◽  
Frank A. Blazich ◽  
Stuart L. Warren
Keyword(s):  
Heat Tolerance ◽  
Leaf Surface ◽  
Dark Respiration ◽  
Temperature Response ◽  
Net Photosynthesis ◽  
Tissue Weight ◽  
Unit Leaf ◽  
Leaf Surface Area ◽  
Temperature Optima ◽  
Two Populations

Temperature sensitivity of net photosynthesis (PN) was evaluated among four taxa of rhododendron including Rhododendron hyperythrum Hayata, R. russatum Balf. & Forr., and plants from two populations (northern and southern provenances) of R. catawbiense Michx. Measurements were conducted on leaves at temperatures rauging from 15 to 40C. Temperature optima for PN ranged from a low of 20C for R. russatum to a high of 25C 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 (LSD0.05 = 1.7). Rhododendron catawbiense from the southern provenance did not appear to have greater heat tolerance than plants from the northern provenance. Differences in dark respiration among taxa were related primarily to differences in tissue weight per unit leaf surface area. Temperature coefficients (Q5) for respiration did not vary in temperature response among taxa. Differences in heat tolerance appeared to result from a combination of stomatal and nonstomatal limitations on PN at high temperatures.

scholarly journals Heat Tolerance of Selected Provenances of Atlantic White Cedar

1999 ◽  
Vol 124 (5) ◽  
pp. 492-497 ◽  
Author(s):  
Laura G. Jull ◽  
Thomas G. Ranney ◽  
Frank A. Blazich
Keyword(s):  
High Temperatures ◽  
Heat Tolerance ◽  
Growth Rates ◽  
Dark Respiration ◽  
Mineral Nutrient ◽  
Limiting Factor ◽  
Temperature Sensitive ◽  
White Cedar ◽  
Atlantic White Cedar ◽  
Temperature Regimes

Seedlings of six provenances of Atlantic white cedar [Chamaecyparis thyoides (L.) B.S.P.] (Escambia Co., Ala., Santa Rosa Co., Fla., Wayne Co., N.C., Burlington Co., N.J., New London Co., Conn., and Barnstable Co., Mass.) were grown in controlled-environment chambers for 12 weeks under 16-hour photoperiods with 16-hour days/8-hour nights of 22/18 °C, 26/22 °C, 30/26 °C, 34/30 °C or 38/34 °C. Considerable variation in height, foliage color, and overall plant size was observed among plants from the various provenances. Seedlings from the two most northern provenances (Massachusetts and Connecticut) were most heat sensitive as indicated by decreasing growth rates at temperature regimes >22/18 °C. In contrast, plants from New Jersey and the three southern provenances (North Carolina, Florida, and Alabama) exhibited greater heat tolerance as indicated by steady or increasing growth rates and greater top and root dry weights as temperature regimes increased above 22/18 °C. Growth rates of seedlings from the four aforementioned provenances decreased rapidly at temperature regimes >30/26 °C suggesting low species tolerance to high temperatures. There were no significant differences in seedling dry matter production among provenances when temperature regimes were ≥34/30 °C. Net shoot photosynthesis and dark respiration of plants did not vary by provenance; however, net photosynthesis was temperature sensitive and decreased at temperature regimes >26/22 °C. Foliar respiration rates increased as temperature increased from 22/18 °C to 26/22 °C, but then remained relatively constant or decreased at higher temperature regimes. Plants at temperatures ≥34/30 °C exhibited severe stunting, chlorosis, and necrosis on branch tips. However, tissue concentrations of N, P, K, Ca, Mg, Fe, Zn, Cu, and Mn generally increased with temperature regimes >30/26 °C indicating that mineral nutrient concentration was not a limiting factor at high temperatures.

scholarly journals Evaluation of Heat and Flood Tolerance among Diverse Taxa of Hollies (Ilex)

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 600d-600
Author(s):  
Thomas G. Ranney ◽  
John M. Ruter ◽  
Clifford D. Ruth
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosynthetic Capacity ◽  
Root Zone ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Flood Tolerance ◽  
Sensitive Species ◽  
Photosynthetic Rates ◽  
Temperature Responses ◽  
Temperature Optima

Temperature sensitivity of net photosynthesis (PSN), dark respiration, and chlorophyll fluorescence was evaluated among three taxa of hollies including I. aquifolium, I. cornuta, and I. rugosa. Variations in foliar heat tolerance among these species were expressed as differential temperature responses for PSN. Temperature optima for PSN was 22.0, 26.3 and 27.9 umol·m–2·s–1 for I. rugosa, I. cornuta, and I. aquifolium, respectively. Differences in temperature optima for PSN and thermotolerance of PSN appeared to result from a combination of stomatal and nonstomatal limitations. At 40°C, potential photosynthetic capacity, measured under saturating CO2, was 4.1, 9.4, and 14.8 μmol·m–2·s–1 for I. rugosa, I. aquifolium, and I. cornuta, respectively. Based on these results, I. rugosa was identified as the most heat-sensitive species followed by I. aquifolium then I. cornuta. Comparative tolerance to root-zone inundation was evaluated among 14 holly taxa. Following 8 weeks of flooding, four of the taxa: I. cornuta `Burfordii', I. × `Nellie R. Stevens', I. cassine, and I. × attenuata `Foster's #2' performed remarkably well during and after flooding with photosynthetic rates > 40% of the controls, root ratings >75% of the controls, <5% of the foliage showing deterioration, and 100% survival. Conversely, I. crenata `Convexa', Ilex × meserveae `Blue Princess', I. rugosa and I. aquifolium `Sparkler' did not tolerate flooding well as indicated by severely depressed photosynthetic rates, deterioration of foliage and roots, and decreased survival. The remaining taxa were intermediate.0

scholarly journals Foliar Heat Tolerance of Three Holly Species (Ilex spp.): Responses of Chlorophyll Fluorescence and Leaf Gas Exchange to Supraoptimal Leaf Temperatures

1997 ◽  
Vol 122 (4) ◽  
pp. 499-503 ◽  
Author(s):  
Thomas G. Ranney ◽  
John M. Ruter
Keyword(s):  
Chlorophyll Fluorescence ◽  
Heat Tolerance ◽  
Photosynthetic Capacity ◽  
Dark Respiration ◽  
Leaf Gas Exchange ◽  
Temperature Threshold ◽  
Contributing Factors ◽  
Ilex Cornuta ◽  
Temperature Responses ◽  
Temperature Optima

Temperature sensitivity of CO2 assimilation (ACO2), dark respiration, and chlorophyll fluorescence was evaluated among three taxa of hollies including I. aquifolium L., I. cornuta Lindl. & Paxt., and I. rugosa Friedr. Schmidt. Variations in foliar heat tolerance among these species were manifested in temperature responses for ACO2. Temperature optima of ACO2 for I. rugosa, I. cornuta, and I. aquifolium were 22.0, 26.3, and 27.9 °C, respectively (LSD0.05 = 2.9). Temperature responses of respiration were similar among taxa and did not appear to be contributing factors to variations in ACO2. At 40 °C, potential photosynthetic capacity, measured under saturating CO2, was 4.1, 9.4, and 14.8 μmol·m-2·s-1 for I. rugosa, I. aquifolium, and I. cornuta, respectively (LSD0.05 = 5.1). Variations in the relative dark-acclimated fluorescence temperature curves were used to assess thresholds for irreversible heat injury. The critical fluorescence temperature threshold (TC) was similar (48.0 °C) for all taxa. The fluorescence temperature peaks (TP) were 52.0, 52.8, and 53.5 °C for I. rugosa, I. cornuta, and I. aquifolium, respectively (LSD0.05 = 0.9). Based on these results, I. rugosa was the most heat-sensitive species, followed by I. aquifolium and I. cornuta. Ilex cornuta also had substantially greater potential photosynthetic capacity than the other species at 40 °C, indicating superior metabolic tolerance to high temperatures.

scholarly journals Basal tolerance to heat and cold exposure of the spotted wing drosophila,Drosophila suzukii

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3112 ◽  
Author(s):  
Thomas Enriquez ◽  
Hervé Colinet
Keyword(s):  
High Temperatures ◽  
Heat Tolerance ◽  
Thermal Tolerance ◽  
Abiotic Factors ◽  
Methodological Approach ◽  
Spotted Wing Drosophila ◽  
Basic Knowledge ◽  
Drosophila Suzukii ◽  
Cold Tolerant ◽  
C 30

The spotted wing Drosophila,Drosophila suzukii, is a new pest in Europe and America which causes severe damages, mostly to stone fruit crops. Temperature and humidity are among the most important abiotic factors governing insect development and fitness. In many situations, temperature can become stressful thus compromising survival. The ability to cope with thermal stress depends on basal level of thermal tolerance. Basic knowledge on temperature-dependent mortality ofD. suzukiiis essential to facilitate management of this pest. The objective of the present study was to investigateD. suzukiibasal cold and heat tolerance. Adults and pupae were subjected to six low temperatures (−5–7.5 °C) and seven high temperatures (30–37 °C) for various durations, and survival-time-temperature relationships were investigated. Data showed that males were globally more cold tolerant than females. At temperature above 5 °C, adult cold mortality became minor even after prolonged exposures (e.g., only 20% mortality after one month at 7.5 °C). Heat tolerance of males was lower than that of females at the highest tested temperatures (34, 35 and 37 °C). Pupae appeared much less cold tolerant than adults at all temperatures (e.g., Lt50at 5° C: 4–5 d for adultsvs.21 h for pupae). Pupae were more heat tolerant than adults at the most extreme high temperatures (e.g., Lt50at 37 °C: 30 min for adultsvs.4 h for pupae). The pupal thermal tolerance was further investigated under lowvs.high humidity. Low relative humidity did not affect pupal cold survival, but it reduced survival under heat stress. Overall, this study shows that survival ofD. suzukiiunder heat and cold conditions can vary with stress intensity, duration, humidity, sex and stage, and the methodological approach used here, which was based on thermal tolerance landscapes, provides a comprehensive description ofD. suzukiithermal tolerance and limits.

Induction of Heat Shock Protein Genes is the Hallmark of Egg Heat Tolerance in Agasicles hygrophila (Coleoptera: Chrysomelidae)

2020 ◽  
Vol 113 (4) ◽  
pp. 1972-1981
Author(s):  
Dong Jia ◽  
Yan-Hong Liu ◽  
Bin Zhang ◽  
Zhou-Yu Ji ◽  
Yuan-Xin Wang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
High Temperatures ◽  
Heat Tolerance ◽  
Invasive Plant ◽  
Alternanthera Philoxeroides ◽  
Alligator Weed ◽  
Natural Habitats ◽  
Hsp Genes

Abstract Insects are ecotothermic organisms. Their development, survival, reproduction as well as distribution and abundance are affected by temperature. Heat shock protein (HSP) gene expression is closely associated with temperature variation and influences the adaptation of organisms to adverse environments. The beetle Agasicles hygrophila has successfully been used for biological control of the invasive plant alligator weed (Alternanthera philoxeroides). As A. hygrophila populations are substantially inhibited by high temperatures in the summer, increasing global temperatures may limit the efficacy of this control agent. We previously established that A. hygrophila eggs have low tolerance to heat and this factored into the decreased numbers of A. hygrophila beetles at temperatures of 37.5°C and above. Here, we identified 26 HSP genes in A. hygrophila and examined the relationship between the transcript levels of these genes and heat tolerance. The temperature at which the expression of these 21 HSP genes peaked (Tpeak) was 37.5°C, which is in line with the limit of the high temperatures that A. hygrophila eggs tolerate. Therefore, we speculate that the Tpeak of HSP gene expression in eggs indicates the upper limit of temperatures that A. hygrophila eggs tolerate. This study identifies HSP genes as potential robust biomarkers and emphasizes that determining species’ heat tolerance in their natural habitats remains an important consideration for biocontrol. HSP gene expression data provide information about a species’ heat tolerance and may be used to predict its geographical distribution.

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.

Sign in / Sign up

Export Citation Format

Share Document