scholarly journals Genotypic Variation in Apple Rootstock Low Temperature Tolerance During Spring and Fall

2018 ◽  
Vol 143 (5) ◽  
pp. 319-332
Author(s):  
Renae E. Moran ◽  
Bryan J. Peterson ◽  
Gennaro Fazio ◽  
John Cline
Keyword(s):  
Low Temperature ◽  
Rating Scale ◽  
Genotypic Variation ◽  
Temperature Tolerance ◽  
Additional Increase ◽  
Cross Sectional ◽  
Low Temperature Tolerance ◽  
Brown Discoloration ◽  
Low Degree ◽  
Similar Rating

To identify genotypes of apple (Malus ×domestica) rootstock with vulnerability to low temperature, we measured the low temperature tolerance of xylem, phloem and cambium in 2-year-old shoot pieces from cultivars Budagovsky 9 (B.9), M.7 EMLA (M.7), M.9 EMLA (M.9), Geneva® 41 (G.41), Geneva 30 (G.30), Geneva 214 (G.214), Geneva 814 (G.814), and Geneva 935 (G.935), as well as six advanced selections in the Geneva (G.) series and three in the Vineland (V.) series. From Oct. 2013 to Apr. 2014, injury was measured as a 0–10 rating based on percentage of discolored cross-sectional xylem and phloem, and cambial length and circumference with brown discoloration, with 0 indicating no browning and 10 indicating browning in the entire tissue. From Oct. 2014 to Apr. 2015, injury was measured as xylem, phloem and cambium browning using a similar rating scale that accounted for both the percentage of browned tissues and the intensity of browning. Following exposure to −35 to −40 °C, many genotypes, including ‘M.7’, ‘M.9’, ‘G.935’, G.4011, G.4292, G.5087, and V.5, had only partial xylem injury in the fall, whereas others, ‘M.7’, ‘G.41’, ‘G.214’, and G.4011, had more extensive xylem browning at −30 °C and colder. ‘G.30’ had moderate to severe xylem browning at −15 to −19 °C. In late October of both years, G.4013 exhibited severe phloem browning at relatively high temperatures, but accrued additional hardiness by Nov. 2014, whereas genotypes ‘B.9’, ‘M.9’, ‘G.30’, and ‘G.41’ developed considerable phloem hardiness by late October with no additional increase in hardiness in November. Geneva and Vineland genotypes exhibited a low degree of susceptibility to injury at −35 to −40 °C in Jan. 2014 and Mar. 2015. Shoot hardiness in Apr. 2014 and 2015 was highly variable between the 2 years, with severe browning of xylem and cambium at −40 °C in every genotype sampled in Apr. 2014, but not in Apr. 2015. ‘M.9’ and G.3902 appeared to be the least vulnerable to injury in April, whereas ‘G.30’, ‘G.41’, ‘G.814’, G.4292, and G.5257 seem more likely to suffer injury in spring. ‘G.30’ had tender xylem in both fall and spring, G.4013 had the least hardy cambium and phloem in fall, and G.5257 the least hardy cambium in the spring. These genotypes are vulnerable to damaging temperatures during fall acclimation and spring deacclimation.

scholarly journals Low Temperature Tolerance of Apple Shoots Following Exposure to Warm Temperatures in Late Winter

HortScience ◽  
2021 ◽  
pp. 1-10
Author(s):  
Renae E. Moran ◽  
Bryan J. Peterson ◽  
Gennaro Fazio ◽  
John A. Cline
Keyword(s):  
Rating Scale ◽  
Tissue Injury ◽  
Genotypic Variation ◽  
Temperature Tolerance ◽  
Late Winter ◽  
Apple Rootstocks ◽  
Yearly Variation ◽  
Cross Sectional ◽  
Low Temperature Tolerance ◽  
One Year

The goal of this research was to evaluate resistance of apple rootstocks to late winter deacclimation during a 2-day exposure to warm temperatures in Maine. We measured the cold temperature tolerance of xylem, phloem, and cambium from 0 to −40 °C in 1- and 2-year-old shoot pieces from apple rootstock cultivars and advanced selections ‘M.9 T337’ (M.9), ‘M.7 EMLA’ (M.7), ‘Budagovsky 9’ (B.9), ‘Geneva® 41’ (G.41), ‘Geneva 30’ (G.30), ‘Geneva 935’ (G.935), ‘Geneva 814’ (G.814), G.4013, G.5257, and Vineland 6 (V.6) after a 2-day exposure to warm (22 °C) or cold (2 to 4 °C) temperatures. Injury was measured on a 0 to 10 rating scale based on percentage of discolored cross-sectional xylem and phloem, and cambial length and circumference with brown discoloration, with 0 indicating no browning and 10 indicating browning in the entire tissue. Injury was also measured as intensity of browning on a scale of 0 (no browning) to 5 (dark brown to black). The weighted averages of the two ratings were used to calculate an index of browning. Genotypic variation occurred in the degree of deacclimation, which ranged from none to as much as 15 °C loss in hardiness. Two genotypes, ‘G.41’ and ‘M.9’, showed little change in hardiness in both years they were tested. Two genotypes, G.4013 and ‘G.814’, lost substantial hardiness in both years and may be vulnerable to late winter freeze-thaw events, but were among the hardiest before deacclimation. ‘G.935’ and G.5257 showed a small loss of hardiness, whereas ‘B.9’ lost hardiness in the cambium, but not the xylem, and V.6 lost hardiness after warm exposure, but showed almost no injury at temperatures as cold as −35 °C. The loss of hardiness of these four genotypes that were tested in only one year should be verified with additional testing because of the potential for yearly variation.

scholarly journals Low temperature tolerance of human embryonic stem cells

2006 ◽  
pp. 124-129 ◽  
Author(s):  
Boon Chin Heng ◽  
Kumar Jayaseelan Vinoth ◽  
Hua Liu ◽  
Manoor Prakash Hande ◽  
Tong Cao
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Low Temperature ◽  
Human Embryonic Stem Cells ◽  
Embryonic Stem ◽  
Temperature Tolerance ◽  
Low Temperature Tolerance

scholarly journals Joint transcriptomic and metabolomic analysis reveals the mechanism of low-temperature tolerance in Hosta ventricosa

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259455
Author(s):  
QianQian Zhuang ◽  
Shaopeng Chen ◽  
ZhiXin Jua ◽  
Yue Yao
Keyword(s):  
Signal Transduction ◽  
Low Temperature ◽  
Temperature Tolerance ◽  
Differentially Expressed ◽  
Metabolomic Analysis ◽  
Temperature Changes ◽  
Low Temperature Tolerance ◽  
Content Ratio ◽  
Temperature Damage ◽  
Hosta Ventricosa

Hosta ventricosa is a robust ornamental perennial plant that can tolerate low temperatures, and which is widely used in urban landscaping design in Northeast China. However, the mechanism of cold-stress tolerance in this species is unclear. A combination of transcriptomic and metabolomic analysis was used to explore the mechanism of low-temperature tolerance in H. ventricosa. A total of 12 059 differentially expressed genes and 131 differentially expressed metabolites were obtained, which were mainly concentrated in the signal transduction and phenylpropanoid metabolic pathways. In the process of low-temperature signal transduction, possibly by transmitting Ca2+ inside and outside the cell through the ion channels on the three cell membranes of COLD, CNGCs and CRLK, H. ventricosa senses temperature changes and stimulates SCRM to combine with DREB through the MAPK signal pathway and Ca2+ signal sensors such as CBL, thus strengthening its low-temperature resistance. The pathways of phenylpropanoid and flavonoid metabolism represent the main mechanism of low-temperature tolerance in this species. The plant protects itself from low-temperature damage by increasing its content of genistein, scopolentin and scopolin. It is speculated that H. ventricosa can also adjust the content ratio of sinapyl alcohol and coniferyl alcohol and thereby alter the morphological structure of its cell walls and so increase its resistance to low temperatures.When subjected to low-temperature stress, H. ventricosa perceives temperature changes via COLD, CNGCs and CRLK, and protection from low-temperature damage is achieved by an increase in the levels of genistein, scopolentin and scopolin through the pathways of phenylpropanoid biosynthesis and flavonoid biosynthesis.

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