Assays to Assess Freeze Injury of Satsuma Mandarin

Nesbitt, Monte; Ebel, Robert C.; Findley, Douglas A.; Wilkins, Bryan; Woods, Floyd M.; Himelrick, David G.

doi:10.21273/hortsci.37.6.871

Cited by 30 publications

(23 citation statements)

References 22 publications

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“…Rootstocks are known to affect canopy development, disease incidence and cold hardiness. Interactions between rootstocks and scions are through exchange of resources and via hormonal messengers (Yelenosky 1985;Jensen et al 2003;Nesbitt et al 2002). The signaling process from rootstock to cellular responses in scion is still poorly understood.…”

Section: Discussionmentioning

confidence: 99%

Impact of grafting on cold responsive gene expression in Satsuma mandarin (Citrus unshiu)

Huang

Dane

2010

Euphytica

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The major limitation preventing the expansion of Satsuma mandarin (Citrus unshiu) production in the Gulf Coast regions of the US is the risk of freeze damage. Poncirus trifoliata (L.) Raf has been widely used as a cold hardy rootstock for citrus production in freeze-prone environments. In this study, relative quantitative real-time RT-PCR was used to study cold responsive genes in Satsuma mandarin (C. unshiu), C. unshiu grafted on P. trifoliata rootstock and P. trifoliata following exposure to cold shock or cold acclimation treatments. Major changes in gene expression occurred in the different species during cold stress especially with respect to nitrate transporter, auxin responsive GH3, UDP-glycosyltransferase (UGT) and chalcone-flavanone isomerase. Very high levels of nitrate transporter were reached early in Poncirus following 60 h of cold shock treatment at 4°C, and in C. unshiu after 3 weeks of gradual cold acclimation. Also, high levels of auxin responsive GH3 were reached in Poncirus following both cold shock and cold acclimation, while levels in C. unshiu were low or reduced. Poncirus rootstock significantly affected gene expression in C. unshiu scion, resulting in a reduction of nitrate transporter, UGT and trehalose 6-phosphate synthase expression levels, and an increase in auxin responsive GH3 gene during cold acclimation. The impact of rootstock on citrus scion during cold stress might be associated with partitioning of nutrients and hormones.

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Section: Discussionmentioning

confidence: 99%

Impact of grafting on cold responsive gene expression in Satsuma mandarin (Citrus unshiu)

Huang

Dane

2010

Euphytica

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“…Freezing treatments. Freezing treatments were conducted after each acclimation treatment using a computer-controlled chest freezer (model FFF25C4AWD; Electrolux Home Products, Inc., Cleveland, Ohio) modifi ed as described previously (Nesbitt et al, 2002). The freezer was further modifi ed by fi tting a Plexi-glass lid with a small access door below the freezer lid, which reduced the change in T air within the freezer headspace as leaves were removed for sampling.…”

Section: Methodsmentioning

confidence: 99%

“…Tree pots were fi tted into styrofoam wells and potting media surfaces were covered with two layers of 1.6-cm-thick styrofoam insulation (R3, Dow, Midland, Mich.) and a layer of 6 mm insulating bubble wrap (R9.8, Refl ectix, Inc., Markleville, Ind.) to prevent potting media from freezing (Nesbitt et al, 2002). The freezer was programmed to drop T air linearly at 2 °C·h -1 to 4 °C and held at that temperature for 1 hour.…”

Section: Methodsmentioning

confidence: 99%

“…Studies that have related ice formation to injury did not use modern technology that allows data collection at high frequency. With the advent of computers, air temperature (T air ) in freeze chambers can be accurately controlled to within ±0.2 °C (Nesbitt et al, 2002), and the latent heat of fusion from ice formation can be measured at high frequency using differential thermal analysis (DTA). Such data may increase understanding of the specifi c mechanism by which intraplant ice causes injury.…”

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confidence: 99%

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Pattern of Exotherm and Electrolyte Leakage Measured at High Frequency of Satsuma Mandarin Exposed to Subfreezing Temperatures

Ebel¹,

Carter²,

Dozier³

et al. 2004

HortSci

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The current study was conducted to relate ice formation to the pattern and rate of leaf and stem injury of Satsuma mandarins on trifoliate orange rootstock. Potted trees were unacclimated, moderately acclimated or fully acclimated by exposing trees to 32/21 °C, 15/7 °C or 10/4 °C, respectively. Freezing treatments consisted of decreasing air temperature at 2 °C·h-1 until ice formed as evidenced by exotherms determined using differential thermal analysis of stems. Air temperature was then decreased, held constant, or increased and held constant to simulate severe, moderate and mild freeze conditions, respectively. All treatment exhibited exotherms at -2 to -4 °C, which were smaller with milder freezing treatments. Only the fully acclimated trees exhibited multiple exotherms. Leaf watersoaking, an indication of ice formation, occurred concurrently with stem exotherms except for fully acclimated trees where there was up to a 30-min delay and which corresponded with the second exotherm. Electrolyte leakage of leaves began to increase near the peak of the stem exotherm, but increased more slowly with milder freezing temperature treatments. In some treatments, electrolyte leakage reached a plateau near 50% but leaves survived. Leaves died when whole-leaf electrolyte leakage exceeded 50%. These data are discussed within the framework of a proposed mechanism of injury of Satsuma mandarin leaves by subfreezing temperatures, especially multiple exotherms of fully acclimated trees, and the plateau of electrolyte leakage of leaves at the critical level for survival.

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“…The principle problem with within-tree microsprinkler irrigation is that the outer canopy can be killed . If leaves are killed but not the fruiting wood, flowers will emerge but abscise Nesbitt et al, 2002). The outer canopy could be protected by overtree sprinkler irrigation, but this approach has been avoided in this region as a result of poor water coverage from the high winds associated with advective freezes, the freezes that cause the most severe injury.…”

Section: Freeze Protection Measuresmentioning

confidence: 99%

Freeze Risk and Protection Measures of Satsuma Mandarins Grown in the Southeastern United States

Ebel¹,

Nesbitt²,

Dozier³

et al. 2008

horts

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The northern fringe of the Gulf of Mexico has an excellent climate for growing high-quality satsumas that are available in U.S. retail chain stores before most other citrus. In part because of high fruit quality, satsuma mandarin production grew into a major industry in Alabama, Louisiana, Mississippi, and the panhandle of Florida in the early 1900s. Freeze protection measures were not sufficient to prevent devastation of the industry by severe freezes. For the period encompassing the late 1900s, freeze risk was estimated using a mathematical approach that determined killing temperature based on air temperature. Freeze injury was determined to occur 1 out of every 4 years on average, although the freezes tended to come in clusters that have as yet not been correlated with long-term climate patterns. Within-tree microsprinkler irrigation, which was not available in the early 1900s, has been shown to reduce the severity of injury. Within-tree microsprinkler irrigation allows full production the year after the freeze, whereas unprotected trees must be grown from the base or replanted. The northerly geographical limit in the southeastern United States whereby satsumas can be successfully grown commercially is currently not known. Methods of protecting the entire tree, including overtree microsprinkler irrigation plus windbreaks and high tunnel houses, are being evaluated. More cold-tolerant satsuma cultivars have been selected, but they reduce freeze risk by at most 2 °C in this region compared with current commercial cultivars. Genetic modification is one possible mechanism for improving cold tolerance sufficiently to reduce freeze risk similar to that of the citrus industry in Florida.

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Assays to Assess Freeze Injury of Satsuma Mandarin

Cited by 30 publications

References 22 publications

Impact of grafting on cold responsive gene expression in Satsuma mandarin (Citrus unshiu)

Impact of grafting on cold responsive gene expression in Satsuma mandarin (Citrus unshiu)

Pattern of Exotherm and Electrolyte Leakage Measured at High Frequency of Satsuma Mandarin Exposed to Subfreezing Temperatures

Freeze Risk and Protection Measures of Satsuma Mandarins Grown in the Southeastern United States

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