Investigations of the Hardiness of Plants by Measurement of Electrical Conductivity

Dexter, S. T.; Tottingham, W. E.; Graber, L. F.

doi:10.1104/pp.7.1.63

Cited by 272 publications

(125 citation statements)

References 10 publications

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“…Changes in osmolyte concentrations are analogous to changes in electrical conductivity, which is commonly used as a measure of cell rupture because the conductivity of extracellular fluids under nonstressed conditions is low and increases significantly upon loss of cellular integrity (Dexter et al, 1932;Sulc et al, 1991). Percentages of total osmolytes present in apoplastic fluid extracted from NH and 1PH tissues were not significantly different from each other (Table I).…”

Section: Indicators Of Cellular Leakagementioning

confidence: 83%

Apoplastic Sugars, Fructans, Fructan Exohydrolase, and Invertase in Winter Oat: Responses to Second-Phase Cold Hardening

1998

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Changes in apoplastic carbohydrate concentrations and activities of carbohydrate-degrading enzymes were determined in crown tissues of oat (Avena sativa L., cv Wintok) during cold hardening. During second-phase hardening (؊3°C for 3 d) levels of fructan, sucrose, glucose, and fructose in the apoplast increased significantly above that in nonhardened and first-phase-hardened plants. The extent of the increase in apoplastic fructan during second-phase hardening varied with the degree of fructan polymerization (DP) (e.g. DP3 and DP4 increased to a greater extent than DP7 and DP > 7). Activities of invertase and fructan exohydrolase in the crown apoplast increased approximately 4-fold over nonhardened and first-phase-hardened plants. Apoplastic fluid extracted from nonhardened, first-phase-hardened, and second-phase-hardened crown tissues had low levels, of symplastic contamination, as determined by malate dehydrogenase activity. The significance of these results in relation to increases in freezing tolerance from second-phase hardening is discussed.Cold-hardening winter cereals such as rye (Secale cereale), wheat (Triticum aestivum), barley (Hordeum vulgare), and oat (Avena sativa) is generally accomplished by exposure to temperatures just above freezing. As early as 1935, Tumenov (cited by Trunova, 1965) reported that an additional phase of hardening by exposure of cold-hardened plants to nonlethal, below-freezing temperatures resulted in significant increases in cold hardiness. Tumenov called this 2PH. With a 2PH treatment, Trunova (1965) and Siminovich (cited by Steponkus, 1978) induced an increase in freezing tolerance of wheat significantly beyond that achieved from cold hardening above freezing (1PH). Olien (1984) reported similar results in rye and barley, and reported a decrease in the LT 50 of oats from Ϫ13°C with 1PH only to Ϫ18°C after a 3-d 2PH period at Ϫ3°C.After 2PH Trunova (1965) found decreased levels of fructan and increased levels of Glc, Fru, and Suc in whole crown tissue of wheat. He suggested that the sugar increase during 2PH was providing osmotic protection to cells in the over-wintering organ (crown) of the plant. Olien (1984), using a perfusion technique, reported an increase in apoplastic sugars during 2PH and suggested that these sugars helped prevent adhesion of ice to critical cellular tissue during freezing.In the present study we wanted to determine the percent distribution of fructan exohydrolase and invertase in the apoplast and symplast of oat crowns, and what the effect of 1PH and 2PH would be on their activities in the respective locations. Additionally, we wanted to determine if fructan was present in the apoplast and the effect of cold hardening on its presence. Finally, we wanted to re-examine the effect of cold hardening on simple sugar levels in the apoplast using a different technique than that used by Olien (1984). MATERIALS AND METHODS Plant CultureSeeds of the oat (Avena sativa L.) cv Wintok were planted in Scotts Metromix 220 1 (Scotts-Sierra Horticultural Products Co...

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Section: Indicators Of Cellular Leakagementioning

confidence: 83%

Apoplastic Sugars, Fructans, Fructan Exohydrolase, and Invertase in Winter Oat: Responses to Second-Phase Cold Hardening

1998

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“…All dead material and plant leaves were removed from the samples. A 10-g portion of prepared crown and root sample was used to measure cold tolerance using the technique of Dexter et al (2). The Following extraction, the solutions were centrifuged at 12,000g for 10 min in a refrigerated centrifuge.…”

Section: Methodsmentioning

confidence: 99%

“…All dead material and plant leaves were removed from the samples. A 10-g portion of prepared crown and root sample was used to measure cold tolerance using the technique of Dexter et al (2). The remainder of each sample was immediately frozen in liquid N2, lyophilized, ground in a Wiley mill to pass through a 40-mesh screen, and stored at -20 C in air-tight vials that were enclosed in plastic bags.…”

mentioning

confidence: 99%

Extractant Influence on the Relationship between Extractable Proteins and Cold Tolerance of Alfalfa

Faw

Shih²,

Jung³

1976

Plant Physiol.

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The influence of ionic composition and pH of extractant on the relationship between the extracted proteins and the cold tolerance of Vernal and Arizona Common alfalfa (Medicago sadiva L.) was examined. Five environments were used to induce different tolerance levels.The quantity of protein extracted from plants was influenced by the hardening environment, cultivar, and ionic composition and pH of 29 extractants. Extractants with a pH below 6 generally extracted less protein.The measured cold tolerance of the plants was correlated with the quantity of protein detected in many of the 14 regions of the electrophoresis gel columns regardless of extractant but was most dosely associated with the protein in either region 7 or 8 with nine of ten extractants. The purpose of this research was to examine the influence of ionic nature and pH of extractants on the relationship between extractable proteins and cold tolerance. Sources of variation in cold tolerance were cultivars of alfalfa and hardening environments. MATERIALS AND METHODSPlant Material. Cans with perforated bottoms and a volume of 3.78 liters were filled with a sandy loam soil and seeded with approximately 50 seeds of cold-tolerant Vernal or cold-sensitive Arizona Common alfalfa (Medicago sativa L.). The seedlings were allowed to grow in the greenhouse for 7 months and then were moved outside in April. The plants were allowed to reach a flowering stage before clipping to maintain high food reserve levels. Insects were controlled by spraying with malathion and Sevin.In late September, the containers were randomly assigned to one of five environments: (a) day and night temperatures of 7 and 2 C, respectively, and a photoperiod of 8 hr; (b) day and night temperatures of 16 and 10 C, respectively, and a photoperiod of 12 hr; (c) natural environment in the field at Morgantown, W. Va.; (d) greenhouse conditions maintained for vigorous growth; and (e) day and night temperatures of 27 and 21 C, respectively, with a photoperiod of 16 hr. Light in the growth chambers was supplied by six cool-white, 40-w fluorescent lamps and four 60-w incandescent bulbs/chamber. This lighting system provided a light intensity of approximately 12,900 lux at the plant tops. Relative humidity was regulated at approximately 80% in the chambers. A randomized block design was used with three replications for each environmental regime.After the plants had been subjected to the environments for 44 to 46 days, they were sampled for cold tolerance determinations and protein analyses. Plant roots were trimmed to a length of approximately 2.5 cm and crowns to 5 cm. All dead material and plant leaves were removed from the samples. A 10-g portion of prepared crown and root sample was used to measure cold tolerance using the technique of Dexter et al. (2). The remainder of each sample was immediately frozen in liquid N2, lyophilized, ground in a Wiley mill to pass through a 40-mesh screen, and stored at -20 C in air-tight vials that were enclosed in plastic bags.

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“…Dexter et al (1930Dexter et al ( , 1932 expressed the conductivity of such exudates as a percentage of the total exudates obtained from the same plant tissue after boiling. Olien (1967) (Fig.…”

Section: Introductionmentioning

confidence: 99%

Electrical Impedance of the Tissue of Grasses Receiving Cold Treatments

Walton¹

1973

Can. J. Plant Sci.

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Investigations of the Hardiness of Plants by Measurement of Electrical Conductivity

Abstract: In a preliminary report, DEXTER. TOTTINGHAMI and GRABER (3)

Cited by 272 publications

References 10 publications

Apoplastic Sugars, Fructans, Fructan Exohydrolase, and Invertase in Winter Oat: Responses to Second-Phase Cold Hardening

Apoplastic Sugars, Fructans, Fructan Exohydrolase, and Invertase in Winter Oat: Responses to Second-Phase Cold Hardening

Extractant Influence on the Relationship between Extractable Proteins and Cold Tolerance of Alfalfa

Electrical Impedance of the Tissue of Grasses Receiving Cold Treatments

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