Summer Air Temperatures as a Factor Affecting Net Photosynthesis and Distribution of Eastern Hemlock (Tsuga canadensis L. (Carriere)) in Southwestern Wisconsin

1971 ◽  
Vol 85 (1) ◽  
pp. 1 ◽  
Author(s):  
Michael S. Adams ◽  
Orie L. Loucks
Keyword(s):  
Net Photosynthesis ◽  
Tsuga Canadensis ◽  
Eastern Hemlock ◽  
Air Temperatures

Impact of hemlock woolly adelgid (Adelges tsugae) infestation on xylem structure and function and leaf physiology in eastern hemlock (Tsuga canadensis)

2018 ◽  
Vol 45 (5) ◽  
pp. 501 ◽  
Author(s):  
Brett A. Huggett ◽  
Jessica A. Savage ◽  
Guang-You Hao ◽  
Evan L. Preisser ◽  
N. Michele Holbrook
Keyword(s):  
Hydraulic Conductivity ◽  
Net Photosynthesis ◽  
Tsuga Canadensis ◽  
Hemlock Woolly Adelgid ◽  
Adelges Tsugae ◽  
Eastern Hemlock ◽  
Xylem Structure ◽  
Leaf Physiology ◽  
Vulnerability To Cavitation ◽  
Needle Loss

Hemlock woolly adelgid (Adelges tsugae Annand) (HWA) is an invasive insect that feeds upon the foliage of eastern hemlock (Tsuga canadensis (L.) Carrière) trees, leading to a decline in health and often mortality. The exact mechanism leading to the demise of eastern hemlocks remains uncertain because little is known about how HWA infestation directly alters the host’s physiology. To evaluate the physiological responses of eastern hemlock during early infestation of HWA, we measured needle loss, xylem hydraulic conductivity, vulnerability to cavitation, tracheid anatomy, leaf-level gas exchange, leaf water potential and foliar cation and nutrient levels on HWA-infested and noninfested even-aged trees in an experimental garden. HWA infestation resulted in higher xylem hydraulic conductivity correlated with an increase in average tracheid lumen area and no difference in vulnerability to cavitation, indicating that needle loss associated with HWA infestation could not be attributed to reduced xylem transport capacity. HWA-infested trees exhibited higher rates of net photosynthesis and significant changes in foliar nutrient partitioning, but showed no differences in branch increment growth rates compared with noninfested trees. This study suggests that HWA-induced decline in the health of eastern hemlock trees is not initially caused by compromised water relations or needle loss.

Frost hardiness and winter photosynthesis of Thujapiicata and Pseudotsugamenzlesll seedlings grown at three rates of nitrogen and phosphorus supply

1995 ◽  
Vol 25 (1) ◽  
pp. 18-28 ◽  
Author(s):  
B.J. Hawkins ◽  
M. Davradou ◽  
D. Pier ◽  
R. Shortt
Keyword(s):  
Net Photosynthesis ◽  
Douglas Fir ◽  
Frost Hardiness ◽  
Nutrient Concentrations ◽  
Nitrogen And Phosphorus ◽  
Red Cedar ◽  
Air Temperatures ◽  
Foliar Nutrient ◽  
One Year ◽  
P Supply

One-year-old seedlings of western red cedar (Thujapiicata Donn ex D.Don) and Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) were grown for one season in five nutrient treatments with nitrogen (N) supplied in solution at rates of 20, 100, or 250 mg•L−1 and phosphorus (P) supplied at rates of 4, 20, or 60 mg•L−1. Growth, onset of dormancy, frost hardiness on six dates, and foliar nutrient concentrations in autumn and spring were measured. Midwinter rates of net photosynthesis and transpiration were measured at air temperatures of 4, 7, and 11 °C in seedlings from all nutrient treatments. Recovery of net photosynthesis and transpiration in whole seedlings from the three N treatments was assessed at intervals for 28 days after the seedlings were frozen to −5, −15, and −25°C. Foliar N content differed significantly among nutrient treatments and was positively correlated with supply. Mitotic activity ceased earliest in plants with low N supply. Douglas-fir seedlings in the low-N treatment also ceased height growth earliest. These differences in growth had no significant correlation with frost hardiness. No consistent differences in frost hardiness among nutrient treatments were observed. Higher rates of N and P supply resulted in higher rates of winter net photosynthesis. Net photosynthesis was reduced dramatically by night frost, with greater damage occurring at lower temperatures. Net photosynthesis recovery occurred most quickly in seedlings with the midrate of N and P supply.

scholarly journals Effect of Radiation and Temperature on Cranberry Photosynthesis and Characterization of Diurnal Change in Photosynthesis

2004 ◽  
Vol 129 (1) ◽  
pp. 106-111 ◽  
Author(s):  
S. Kumudini
Keyword(s):  
Net Photosynthesis ◽  
Vaccinium Macrocarpon ◽  
Controlled Environment ◽  
Photosynthetic Response ◽  
Radiation Level ◽  
Photosynthetic Rates ◽  
Air Temperatures ◽  
Predicted Values ◽  
The Impact

Cranberry [Vaccinium macrocarpon (Ait.)] yield has been associated with photosynthate supply. However, the impact of temperature and radiation on photosynthesis of the cranberry plant is not well understood. The objective of this experiment was to characterize the photosynthetic response to radiation and temperature in order to develop a model for estimation of cranberry photosynthetic rates. Two cranberry cultivars, `Stevens' and `Ben Lear', were tested for photosynthetic response at air temperatures ranging from 15 to 35 °C and radiation intensities from 200 to 1200 μmol·m-2·s-1. Depending on temperature, maximum photosynthesis (Pmax) was ≈10 or 12 μmol CO2/m2/s (net photosynthesis) and the saturating radiation level was estimated to be 600 to 800 μmol·m-2·s-1. Cranberry quantum yield was estimated as 0.03 mol CO2/mol photon. Both models; Blackman and the nonrectangular hyperbola with a Θ (angle of curvature) of 0.99 were a good fit for measured photosynthetic rates under controlled environment conditions. The disparity between modeled predicted values, and observed values in the field around midday, indicates a reduction in potential photosynthetic rates in a diurnal cycle that is consistent with the phenomenon of midday depression.

scholarly journals LOGS AS REFUGES FROM FUNGAL PATHOGENS FOR SEEDS OF EASTERN HEMLOCK (TSUGA CANADENSIS)

Ecology ◽  
2004 ◽  
Vol 85 (1) ◽  
pp. 284-289 ◽  
Author(s):  
D. L. O'Hanlon-Manners ◽  
P. M. Kotanen
Keyword(s):  
Fungal Pathogens ◽  
Tsuga Canadensis ◽  
Eastern Hemlock

USE OF THE RELATIVE TURGIDITY TECHNIQUE FOR MEASUREMENT OF WATER STRESSES IN GYMNOSPERM LEAVES

1965 ◽  
Vol 43 (2) ◽  
pp. 305-316 ◽  
Author(s):  
J. J. Clausen ◽  
T. T. Kozlowski
Keyword(s):  
Abies Balsamea ◽  
Pinus Resinosa ◽  
Tsuga Canadensis ◽  
Red Pine ◽  
Eastern Hemlock ◽  
Balsam Fir ◽  
White Pine ◽  
Sampling Variation

Adaptations of Weatherley's relative turgidity technique (Weatherley 1950), fitting it for use with red pine (Pinus resinosa Ait.), white pine (P. strobus L.), balsam fir (Abies balsamea (L.) Mill.), and eastern hemlock (Tsuga canadensis (L.) Carr.) are described. Results of preliminary investigations of sampling variation between trees, whorls, and needle ages in red pine are presented.

Combined Effects of Hemlock Woolly Adelgid (Adelges tsugae) Infestation and Treatment with Imidacloprid on Eastern Hemlock (Tsuga canadensis) Leaf Radiometry

2019 ◽  
Vol 117 (4) ◽  
pp. 340-350 ◽  
Author(s):  
Heath W Garris ◽  
Thomas H Settle ◽  
Jonathan E Crossman ◽  
Stephen J Grider ◽  
Shawnté L Michaels
Keyword(s):  
Optical Properties ◽  
Tsuga Canadensis ◽  
Hemlock Woolly Adelgid ◽  
Adelges Tsugae ◽  
Eastern Hemlock ◽  
Abiotic Stressors ◽  
Leaf Optical Properties ◽  
Photosynthetic Potential ◽  
And Control ◽  
Potential Efficiency

Abstract The neonicotinoid systemic insecticide imidacloprid has proven to be an effective treatment for the prevention and control of hemlock woolly adelgid (Adelges tsugae Annand) in southeastern populations of eastern hemlock (Tsuga canadensis L.). Recent studies have demonstrated that imidacloprid and A. tsugae both stimulate salicylic acid-dependent physiological responses in plant tissues responsible for plant defenses against pathogens, timing of developmental outcomes including flowering and leaf senescence, and resilience to abiotic stressors. We evaluated the interacting effects of A. tsugae presence/absence and treatment with imidacloprid on leaf optical properties indicative of photosynthetic potential, photosynthetic efficiency, and tissue senescence. Our results indicated that A. tsugae changes lower canopy leaf optical properties indicative of reduced photosynthetic potential/efficiency and accelerated senescence in mature leaves. Imidacloprid was associated with declines in photosynthetic potential and showed a largely similar, though less pronounced, effect on leaf spectral properties to that of A. tsugae.

The genetic diversity of disjunct populations of Eastern hemlock (Tsuga canadensis) in Minnesota

2018 ◽  
pp. 225-234
Author(s):  
E. Ellingson ◽  
S. McNamara ◽  
J.M. Bradeen ◽  
S.C. Hokanson
Keyword(s):  
Genetic Diversity ◽  
Tsuga Canadensis ◽  
Eastern Hemlock ◽  
Disjunct Populations

Characterization of the Soil Hydromorphic Conditions in a Paludified Dunefield during the Mid-Holocene Hemlock Decline near Québec City, Québec

1996 ◽  
Vol 46 (3) ◽  
pp. 281-297 ◽  
Author(s):  
Najat Bhiry ◽  
Louise Filion
Keyword(s):  
Soil Fauna ◽  
Tsuga Canadensis ◽  
Eastern Hemlock ◽  
Plant Colonization ◽  
Quebec City ◽  
Hemlock Decline ◽  
Short Period ◽  
Time Required ◽  
Hemlock Looper

The mid-Holocene eastern hemlock [Tsuga canadensis L. (Carr.)] decline has been recently attributed to the activity of insect defoliators. N. Bihiry and L. Filion, Quaternary Research 45,312–320 (1996). In this study, soil hydromorphic conditions were investigated for the period 6800–3200 yr B.P. using micromorphological data from a peat section from a swale in a paludified dunefield in southern Québec. After a short period of plant colonization in shallow pools between 6800 and 6400 yr B.P., mesic conditions predominated in the interdune before the decline (6400–4900 yr B.P.), as evidenced by strong bioturbation and abundance of excrements from the soil fauna. During the decline, a shift from mesic to wet conditions occurred (4900–4100 yr B.P.), although xeric to mesic conditions persisted on dune ridges until at least 4200 yr B.P. Wetness culminated when beaver occupied the site (4100–3750 yr B.P.). Hemlock needles with chewing damage typical of hemlock looper (Lambdina fiscellaria) feeding were identified at levels dated 4900, 4600, and 4200 yr B.P., respectively, implying that the hemlock decline was associated with at least three defoliation events. The ca. 400-yr interval between these events likely represents the time required for this late-sucessional tree species to recover.

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