scholarly journals Midwinter dehardening of montane red spruce during a natural thaw

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.

2002 ◽  
Vol 32 (8) ◽  
pp. 1351-1359 ◽  
Author(s):  
Paul G Schaberg ◽  
Donald H DeHayes ◽  
Gary J Hawley ◽  
Paula F Murakami ◽  
G Richard Strimbeck ◽  
...  

We evaluated the influence of protracted low-level nitrogen (N) fertilization on foliar membrane-associated calcium (mCa), sugar and starch concentrations, membrane stability, winter cold tolerance, and freezing injury of red spruce (Picea rubens Sarg.) trees growing in six experimental plots on Mount Ascutney, Vermont. For 12 consecutive years before this evaluation, each plot received one of three treatments: 0, 15.7, or 31.4 kg N·ha–1·year–1 supplied as NH4Cl. In comparison with trees from control plots, the current-year foliage of trees from N-addition plots had lower mCa concentrations, higher levels of electrolyte leakage, reduced cold tolerance, and greater freezing injury. Levels of mCa, membrane stability, and cold tolerance did not differ between N treatments, but trees in high-N treated plots experienced greater freezing injury. Although no differences in carbohydrate nutrition were detected in September, foliar sugar and starch concentrations from trees in N-treated plots were higher than control plot trees in January. We propose that foliar mCa deficiencies reduced cell membrane stability, decreased cold tolerance, and increased freezing injury for trees in N addition plots relative to controls. Declines in mCa may also help account for increases in respiration previously measured. Because soil, root, and mycorryhizal conditions were not evaluated, it is unknown how treatment-induced changes in these compartments may have influenced the alterations in foliar mCa and physiological parameters measured in this study.


Author(s):  
Paul Schaberg ◽  
Paula Murakami ◽  
Christopher F. Hansen ◽  
Gary J. Hawley ◽  
Christian O. Marks ◽  
...  

Although Dutch elm disease (DED) is the primary threat to American elm (Ulmus americana L.), we hypothesized that shoot freezing injury may also limit tree productivity and survival in the north. We assessed shoot cold tolerance and field winter injury of American elm bred for DED tolerance planted in Lemington, VT. We tested for differences in cold tolerance associated with date, maternal DED tolerance source, paternal sources from plant hardiness zones 5a, 6a and 6b (determined using data from 1996-2005), and the interactions of these. Cold tolerance was greatest in the winter, followed by fall and then spring. For all dates, cold tolerance never differed between maternal DED tolerance sources. However, in mid-winter, paternal sources from zone 5a (coldest zone) were significantly more cold tolerant than sources from zone 6b (warmest zone), and sources from zone 6a were intermediate. Field freezing injury confirmed that shoots were only marginally cold tolerant relative to ambient temperature lows.


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.


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.


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.


1989 ◽  
Vol 19 (6) ◽  
pp. 754-758 ◽  
Author(s):  
Richard M. Klein ◽  
Timothy D. Perkins ◽  
Helen L. Myers

Increased ecosystem loading with inorganic nitrogen compounds derived from anthropogenic sources has been proposed to prolong vegetative growth of spruce, rendering them more susceptible to winter injury. Severely nutrient-deficient 4-year-old red spruce (Picearubens Sarg.) seedlings and adequately fertilized seedlings were provided with synthetic cloud water lacking or containing nitrate, ammonium, or both, for a full growing season, and then exposed to normal winter chilling. Needles from these seedlings were stressed at −25 or −30 °C, and freezing injury was measured as ion leakage. Cloud water condensates had no effect on hardiness of needles of either nutrient status. Initially nutrient-sufficient seedlings transferred to nutrient-deficient conditions also exhibited no change in hardiness. Severely nutrient-deficient seedlings had needles that were significantly more sensitive to winter injury than seedlings under nutrient-sufficient conditions. Improving the nutrient status of initially nitrogen-deficient seedlings reduced their sensitivity to freezing injury. Based upon experimental results and consideration of the amounts of inorganic nitrogen reaching upper-elevation conifer forests, there is no evidence to support the hypothesis that anthropogenic nitrogen supplies significantly reduce winter hardiness of spruce foliage. It is improbable that winter injury due to elevated anthropogenic nitrogen is a causal factor in contemporary forest decline.


2020 ◽  
Author(s):  
Changbing Huang ◽  
Chun Jiang ◽  
limin Jin ◽  
Huanchao Zhang

Abstract Background:Hemerocallis fulva is a perennial herb belonging to Hemerocallis of Hemerocallis. Because of the large and bright colors, it is often used as a garden ornamental plant. But most varieties of H. fulva on the market will wither in winter, which will affect their beauty. It is very important to study the effect of low temperature stress on the physiological indexes of H. fulva and understand the cold tolerance of different H. fulva. MiRNA is a kind of endogenous non coding small molecular RNA with length of 21-24nt. It mainly inhibits protein translation by cutting target genes, and plays an important role in the development of organisms, gene expression and biological stress. Low temperature is the main abiotic stress affecting the production of H. fulva in China, which hinders the growth and development of plants. A comprehensive understanding of the expression pattern of microRNA in H. fulva under low temperature stress can improve our understanding of microRNA mediated stress response. Although there are many studies on miRNAs of various plants under cold stress at home and abroad, there are few studies on miRNAs related to cold stress of H. fulva. It is of great significance to explore the cold stress resistant gene resources of H. fulva, especially the identification and functional research of miRNA closely related to cold stress, for the breeding of excellent H. fulva.Results A total of 5619 cold-responsive miRNAs, 315 putative novel and 5 304 conserved miRNAs, were identified from the leaves and roots of two different varieties ‘Jinyan’ (cold-tolerant) and ‘Lucretius ’ (cold-sensitive), which were stressed under -4 oC for 24 h. Twelve conserved and three novel miRNAs (novel-miR10, novel-miR19 and novel-miR48) were differentially expressed in leaves of ‘Jinyan’ under cold stress. Novel-miR19, novel-miR29 and novel-miR30 were up-regulated in roots of ‘Jinyan’ under cold stress. Thirteen and two conserved miRNAs were deferentially expressed in leaves and roots of ‘Lucretius’ after cold stress. The deferentially expressed miRNAs between two cultivars under cold stress include novel miRNAs and the members of the miR156, miR166 and miR319 families. A total of 6 598 target genes for 6 516 known miRNAs and 82 novel miRNAs were predicted by bioinformatic analysis, mainly involved in metabolic processes and stress responses. Ten differentially expressed miRNAs and predicted target genes were confirmed by quantitative reverse transcription PCR(q-PCR), and the expressional changes of target genes were negatively correlated to differentially expressed miRNAs. Our data indicated that some candidate miRNAs (e.g., miR156a-3-p, miR319a, and novel-miR19) may play important roles in plant response to cold stress.Conclusions Our study indicates that some putative target genes and miRNA mediated metabolic processes and stress responses are significant to cold tolerance in H. fulva.


Author(s):  
Toshitake Araie ◽  
◽  
Ikeda Tomozumi ◽  
Akira Kakimoto ◽  
Shunsuke Adachi ◽  
...  

Agricultural tasks result in significant strain on the arms, thereby necessitating posture support. One such task is measuring the photosynthetic capacity of individual leaves. This task requires the operator to hold a measuring device for long periods, which is physically demanding. This study aims to develop an assist suit to reduce the physical load involved in photosynthesis measurement work. We used work posture evaluation methods to quantify the workload of this task and identified the parts of the body at high-risk of injury. Then, we designed an assist suit based on the required specifications and verified its effectiveness.


2006 ◽  
Vol 63 (3) ◽  
pp. 255-261 ◽  
Author(s):  
Renata Pereira da Cruz ◽  
Sandra Cristina Kothe Milach ◽  
Luiz Carlos Federizzi

Cold tolerance of rice (Oryza sativa L.) during the reproductive stage is important to guarantee high yield under low temperature environments. Field selection, however, does not allow identification of adequate tolerance sources and limits selection of segregating lines due to variable temperature. The objective of this study was to devise methods for distinguishing rice genotypes as to their cold tolerance at the reproductive stage when evaluated under controlled temperature. The effect of cold temperatures was investigated in six rice genotypes at 17°C for varying length of time (three, five, seven and ten days) at two reproductive stages (microsporogenesis and anthesis). Cold tolerance was measured as the percentage of reduction in panicle exsertion and in spikelet fertility. Evaluating cold tolerance through the reduction in panicle exsertion did not allow for the distinction between cold tolerant from cold sensitive genotypes and, when the reduction in spikelet fertility was considered, a minimum of seven days was required to differentiate the genotypes for cold tolerance. Genotypes were more sensitive to cold at anthesis than at microsporogenesis and, as these stages were highly correlated, cold screening could be performed at anthesis only, since it is easier to determine. Rice cold tolerance at the reproductive stage may be characterized by the reduction in spikelet fertility due to cold temperature (17°C) applied for seven days at anthesis.


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