Ambient cloud deposition reduces cold tolerance of red spruce seedlings

1991 ◽  
Vol 21 (8) ◽  
pp. 1292-1295 ◽  
Author(s):  
D. H. DeHayes ◽  
F. C. Thornton ◽  
C. E. Waite ◽  
M. A. Ingle

Laboratory cold-tolerance assessments were conducted between September 1989 and March 1990 on red spruce (Picearubens Sarg.) seedlings exposed to combinations of ozone (O3) and cloud water for two growing seasons on the summit of Whitetop Mountain, Virginia. Chamber treatments consisted of exposure to (i) ambient O3 and cloud water, (ii) ambient O3 and no cloud water, or (iii) reduced O3 and no cloud water. Ambient-air field plots were included to assess possible chamber effects. Red spruce seedlings exposed to ambient O3 and cloud water, either in chambers or field plots, were generally least cold tolerant, and differences were significant in October, November, December, and January. During 3 of those months, seedlings exposed to ambient O3 and cloud water in chambers were significantly less cold tolerant than either seedlings exposed to reduced O3 and no cloud water or seedlings exposed to ambient O3 only. There were no definitive effects of O3 in any month. The reduction in cold tolerance of seedlings exposed to O3 and cloud water appeared to result from the negative influences of acidic cloud deposition, rather than O3. This is the first conclusive evidence that ambient cloud deposition can impair the development of cold tolerance and maximum cold tolerance achieved in midwinter for red spruce growing in its native habitat. The 3 to 5 °C reduction in cold tolerance associated with exposure to ambient cloud water in this study may be sufficient to explain the winter injury observed frequently in northern montane red spruce stands over the past 4 decades.

1995 ◽  
Vol 25 (12) ◽  
pp. 2040-2044 ◽  
Author(s):  
G.R. Strimbeck ◽  
D.H. DeHayes ◽  
J.B. Shane ◽  
G.J. Hawley ◽  
P.G. Schaberg

We documented 3 to 14 °C of dehardening in current-year foliage of 10 mature, montane red spruce (Picearubens Sarg.) trees during a natural thaw from 12 to 21 January 1995. Mean cold tolerance was about −47 °C before the onset of thaw conditions, and individuals ranged from −38 to −52 °C. After 3 days of thaw, mean cold tolerance dropped to −39 °C, with a range of −32 to −44 °C. Trees did not regain prethaw levels of cold tolerance until sometime between 31 January and 9 February, or 10 to 20 days after subfreezing temperatures resumed. The least cold tolerant tree was at risk of injury when temperature at the field site fell to an estimated −33.8 °C on 6 February, and this same tree developed noticeably more injury than other trees when injury symptoms developed in late March. No evidence of dehardening was found in balsam fir (Abiesbalsamea (L.) Mill.) trees from the same stand. All red spruce trees also showed the potential for net assimilation of carbon during the thaw, as determined by measurement of photosynthetic capacity under laboratory conditions. From the abrupt and substantial dehardening and persistence of the dehardened state, we conclude that dehardening during periods of warm weather may be a significant factor in freezing injury and decline of montane red spruce populations.


1989 ◽  
Vol 19 (8) ◽  
pp. 1037-1043 ◽  
Author(s):  
D. H. DeHayes ◽  
M. A. Ingle ◽  
C. E. Waite

Red spruce (Picearubens Sarg.) seedlings were treated with one of four concentrations of NH4NO3 (0, 300, 1500, and 3000 kg N•ha−1•year−1) applied to the soil, with and without triple superphosphate, during early, mid-, or late summer. Laboratory freezing assessments indicated that cold tolerance of treated seedlings generally increased with increasing nitrogen (N) uptake, with the exception of the highest N treatment. Seedlings receiving 1500 kg N•ha−1•year−1 were most cold tolerant on most sample dates. In general, these seedlings were hardier than those receiving 300 kg N•ha−1•year−1, which were hardier than unfertilized control seedlings. Seedlings receiving supplemental N also acclimated to cold more rapidly in autumn and deacclimated more slowly in spring than unfertilized controls. Supplemental phosphorus (P) had no influence on cold tolerance, and there was no evidence of a N × P interaction. Significant differences in cold tolerance associated with time of N application (early, mid-, and late summer) were detected in autumn and winter, but not in spring. In general, seedlings receiving N in mid- or late summer were as hardy or hardier than seedlings fertilized in early summer, regardless of the concentration of fertilizer. Significant interactions between N and timing of treatments occurred primarily because N applied in early summer resulted in only a slight increase in cold tolerance, whereas mid- and late summer N application resulted in a substantial increase in cold tolerance. Combined results suggest that it is highly unlikely that either the amount or timing of atmospheric N deposition is responsible for the winter injury frequently observed in red spruce.


HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1004B-1004
Author(s):  
Matthew Chappell ◽  
Carol Robacker

While the recommended time to prune abelia is before spring growth initiates, the actual pruning time is often variable and dependent upon labor and plant appearance. As abelia suffers from freeze damage north of zone 8A, pruning may have an impact on the level of freeze damage. Six Abelia genotypes were established in replicated field plots in Griffin, Ga., in 1999. On 3–4 July 2003, half the individuals of each genotype were severely pruned (75% of growth removed). Subsequently, 80 uniform-sized stem tips were randomly collected from plants of each genotype–treatment combination once per month from Oct. 2003 through Apr. 2004. Stem sections were exposed to predetermined temperatures ranging from –3 °C to –27 °C in a temperature bath. The number of stem sections killed in each of two replications out of four possible stem sections was recorded (0 = none dead; 4 = all dead). Data were analyzed with SAS using the Genmod procedure to acquire seasonal results as well as with PROC GLM and means separation to acquire monthly results. Using the Genmod procedure, all genotypes with the exception of `Canyon Creek' were significantly more cold tolerant in unpruned compared to pruned treatments. In this study, Dec. 2003 was the first month with temperatures below freezing at the test site. Proc GLM analysis indicated a significant difference between the pruned and unpruned treatments in Dec. 2003–Feb. 2004. Results of the Proc GLM analysis for the months of Oct. and Nov. 2003 as well as Mar. and Apr. 2004 were nonsignificant (P < 0.05) due to an absence of cold acclimation. These results indicate that mid-season pruning of Abelia genotypes can significantly reduce cold hardiness and lead to serious stem dieback in pruned plants.


1986 ◽  
Vol 64 (4) ◽  
pp. 760-768 ◽  
Author(s):  
G. F. Bills ◽  
G. I. Holtzman ◽  
O. K. Miller Jr.

Sporocarps of Basidiomycetes belonging to families containing some species known to form ectomycorrhizae were enumerated in 12 plots (16 × 16 m) subdivided into contiguous 2 × 2 m quadrats during the growing seasons of 1981 – 1983. Plots were distributed equally between homogeneous second-growth red spruce stands and heterogeneous northern hardwood stands in southeastern West Virginia. A few major species accounted for most of the abundance, while most species fruited rarely, but abundance and phenology varied broadly from year to year, apparently in response to rainfall and temperature. Fungal species composition, spatial frequency, and sporocarp density in the two forest types differed as would be expected in light of the symbiotic nature of the fungi and trees considered. Of 54 fungal species encountered over 3 years, 19 occurred exclusively in spruce plots, 27 occurred exclusively in hardwood plots, and 8 occurred in both forest types. In both forest types, approximately 40% of the species were Russulaceae. Species frequency and sporocarp abundance were greater in spruce plots than in hardwood plots. The Shannon–Wiener index, the dominance–diversity curve, the species–area curve, and ordination confirmed that fungal species richness, equitability, and diversity were greater in the mixed-hardwood plots, which hosted many rare fungal species, than in the single-species coniferous plots, which were dominated by a few ubiquitous fungal species.


2019 ◽  
Vol 374 (1778) ◽  
pp. 20180548 ◽  
Author(s):  
Heidi J. MacLean ◽  
Jesper G. Sørensen ◽  
Torsten N. Kristensen ◽  
Volker Loeschcke ◽  
Kristian Beedholm ◽  
...  

The thermal biology of ectotherms is often used to infer species' responses to changes in temperature. It is often proposed that temperate species are more cold-tolerant, less heat-tolerant, more plastic, have broader thermal performance curves (TPCs) and lower optimal temperatures when compared to tropical species. However, relatively little empirical work has provided support for this using large interspecific studies. In the present study, we measure thermal tolerance limits and thermal performance in 22 species of Drosophila that developed under common conditions. Specifically, we measure thermal tolerance (CT min and CT max ) as well as the fitness components viability, developmental speed and fecundity at seven temperatures to construct TPCs for each of these species. For 10 of the species, we also measure thermal tolerance and thermal performance following developmental acclimation to three additional temperatures. Using these data, we test several fundamental hypotheses about the evolution and plasticity of heat and cold resistance and thermal performance. We find that cold tolerance (CT min ) varied between the species according to the environmental temperature in the habitat from which they originated. These data support the idea that the evolution of cold tolerance has allowed species to persist in colder environments. However, contrary to expectation, we find that optimal temperature ( T opt ) and the breadth of thermal performance ( T breadth ) are similar in temperate, widespread and tropical species and we also find that the plasticity of TPCs was constrained. We suggest that the temperature range for optimal thermal performance is either fixed or under selection by the more similar temperatures that prevail during growing seasons. As a consequence, we find that T opt and T breadth are of limited value for predicting past, present and future distributions of species. This article is part of the theme issue ‘Physiological diversity, biodiversity patterns and global climate change: testing key hypotheses involving temperature and oxygen’.


1989 ◽  
Vol 19 (3) ◽  
pp. 382-386 ◽  
Author(s):  
Richard D. Bowden ◽  
Gordon T. Geballe ◽  
William B. Bowden

One hypothesis to explain dieback of red spruce (Picearubens Sarg.) trees in high-elevation red spruce stands is that atmospheric deposition may introduce nitrogen in excess of plant needs (N saturation), which may disrupt normal metabolism and foliage development in this harsh environment. Some authors suggest that direct foliar uptake of N might contribute to N saturation. To examine the importance of foliar uptake by red spruce, we exposed seedlings in a greenhouse to a mist that simulated cloud water and contained either ammonium or nitrate as 15N (99 at.% excess at 2 mg/L). After 50 h exposure to mist, seedlings were washed and then separated into four tissue types: new foliage, old needles, stems, and roots. Total and isotopic nitrogen contents were determined for each tissue type. The accumulation rate of 15N in each tissue type was very low. Extrapolating our data on the basis of a year suggests that N from cloud water supplies only a small fraction of the N required for new growth (less than 1.5% for the seedlings we used). We observed that both ammonium-15N and nitrate-15N accumulated in stem tissues and could not be removed after repeated washings, which suggests an alternative mechanism for long-term N retention by red spruce stands.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jie Gao ◽  
Tongxin Dou ◽  
Weidi He ◽  
Ou Sheng ◽  
Fangcheng Bi ◽  
...  

Abstract Background Banana is a tropical fruit with a high economic impact worldwide. Cold stress greatly affects the development and production of banana. Results In the present study, we investigated the functions of MaMAPK3 and MaICE1 involved in cold tolerance of banana. The effect of RNAi of MaMAPK3 on Dajiao (Musa spp. ‘Dajiao’; ABB Group) cold tolerance was evaluated. The leaves of the MaMAPK3 RNAi transgenic plants showed wilting and severe necrotic symptoms, while the wide-type (WT) plants remained normal after cold exposure. RNAi of MaMAPK3 significantly changed the expressions of the cold-responsive genes, and the oxidoreductase activity was significantly changed in WT plants, while no changes in transgenic plants were observed. MaICE1 interacted with MaMAPK3, and the expression level of MaICE1 was significantly decreased in MaMAPK3 RNAi transgenic plants. Over-expression of MaICE1 in Cavendish banana (Musa spp. AAA group) indicated that the cold resistance of transgenic plants was superior to that of the WT plants. The POD P7 gene was significantly up-regulated in MaICE1-overexpressing transgenic plants compared with WT plants, and the POD P7 was proved to interact with MaICE1. Conclusions Taken together, our work provided new and solid evidence that MaMAPK3-MaICE1-MaPOD P7 pathway positively improved the cold tolerance in monocotyledon banana, shedding light on molecular breeding for the cold-tolerant banana or other agricultural species.


2020 ◽  
pp. 1-31
Author(s):  
Clay M. Perkins ◽  
Thomas C. Mueller ◽  
Lawrence E. Steckel

Abstract Junglerice has become a major weed in Tennessee cotton and soybean fields. Glyphosate has been relied upon to control these accessions over the past two decades but in recent years cotton and soybean producers have reported junglerice escapes after glyphosate + dicamba and/or clethodim applications. In the growing seasons of 2018 and 2019, a survey was conducted of weed escapes in dicamba-resistant crops. Junglerice was the most prevalent weed escape in these dicamba-resistant (Roundup Ready Xtend®) cotton and soybean fields in both years of the study. In 2018 and 2019, junglerice was found 76% and 64% of the time in dicamba-resistant cotton and soybean fields, respectively. Progeny from junglerice seeds collected during this survey was screened for glyphosate and clethodim resistance. Seventy percent of the junglerice accessions tested had an effective relative resistance factor (RRF) of 3.1 to 8.5 to glyphosate. In all, 13% of the junglerice accessions could no longer be effectively controlled with glyphosate. This research also showed that all sampled accessions could still be controlled with clethodim in a greenhouse environment but less control was observed in the field. These data would also suggest that another cause for the poor junglerice control is dicamba antagonizing the glyphosate and clethodim activity.


1994 ◽  
Vol 24 (5) ◽  
pp. 954-959 ◽  
Author(s):  
L.J. Samuelson ◽  
J.R. Seiler

The interactive influences of ambient (374 μL•L−1) or elevated (713 μL•L−1) CO2, low or high soil fertility, well-watered or water-stressed treatment, and rooting volume on gas exchange and growth were examined in red spruce (Picearubens Sarg.) grown from seed through two growing seasons. Leaf gas exchange throughout two growing seasons and growth after two growing seasons in response to elevated CO2 were independent of soil fertility and water-stress treatments, and rooting volume. During the first growing season, no reduction in leaf photosynthesis of seedlings grown in elevated CO2 compared with seedlings grown in ambient CO2 was observed when measured at the same CO2 concentration. During the second growing season, net photosynthesis was up to 21% lower for elevated CO2-grown seedlings than for ambient CO2-grown seedlings when measured at 358 μL•L−1. Thus, photosynthetic acclimation to growth in elevated CO2 occurred gradually and was not a function of root-sink strength or soil-fertility treatment. However, net photosynthesis of seedlings grown and measured at an elevated CO2 concentration was still over 2 times greater than the photosynthesis of seedlings grown and measured at an ambient CO2 concentration. Growth enhancement by CO2 was maintained, since seedlings grown in elevated CO2 were 40% larger in both size and weight after two growing seasons.


1972 ◽  
Vol 52 (2) ◽  
pp. 199-208 ◽  
Author(s):  
K. C. IVARSON ◽  
A. R. MACK

Studies were made on the root-surface fungi of soybean grown in field plots where various soil temperature and moisture environments had been maintained for five previous growing seasons. Washed-root segments were incubated on agar plates at temperatures corresponding to those of the field plots. Fusarium was the most abundant genus appearing on the plates. Species of Mucor, Trichoderma, Alternaria, Mortierella, Aspergillus, Corynespora, Rhizoctonia, Penicillium, Gliocladium, and sterile forms appeared fairly frequently. Statistical analysis of the data revealed that changes in soil and incubation temperature markedly affected the relative frequency of 12 genera, and age of plant significantly affected nine genera. Soil moisture influenced the frequency of only one genus. High soil and incubation temperature (28 C) encouraged greater root populations of Rhizoctonia early in the season, Trichoderma and Aspergillus throughout the growing season, and Fusarium late in the season. Low soil temperature conditions (12 C) favored growth of Pythium, Mortierella, Mucor, Alternaria, Cladosporium, throughout the growing season, and Corynespora and Cylindrocarpon, primarily during mid-season. Late in the season Gliocladium preferred the intermediate temperature of 20 C.


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