Seasonal changes in soluble protein, nucleic acids, and tissue pH related to cold hardiness of alfalfa

Jung, G. A.; Shih, S. C.; Shelton, D. C.

doi:10.1016/s0011-2240(67)80181-0

Cited by 38 publications

(16 citation statements)

References 12 publications

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“…This study seemed particularly appropriate because consistent increases in pH of plant sap have been observed during the acquisition of cold tolerance and the rises in pH were greater in cold-tolerant than cold-sensitive cultivars (6,7,11,12). Foliar applications of purines and pyrimidines that increased cold tolerance also tended to increase pH of plant sap (6).…”

Section: Discussionmentioning

confidence: 87%

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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Section: Discussionmentioning

confidence: 87%

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

Faw

Shih²,

Jung³

1976

Plant Physiol.

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“…Thus, it often has been assumed that proteins do not play significant roles in the storage of nitrogen in roots. However, water-extractable proteins are associated with cold (Koperzinskii 1939, Jung et al 1967, Faw et al 1976) and freezing tolerance (Perras and Sarhan 1989) of roots. The trends observed in soluble protein in leafy spurge are strongly suggestive of an important role in overwintering strategy.…”

Section: Resultsmentioning

confidence: 99%

Carbon and nitrogen reserves of leafy spurge (Euphorbia esula) roots as related to overwintering strategy

Cyr

Bewley

1989

Physiologia Plantarum

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Abstract:Leafy spurge (Euphorbia esula L.), a serious perennial weed of temperature range and pasture lands, has continued to colonize despite various control strategies. The persistence of this species can be attributed in part to the presence of an extensive root system containing abundant organic reserves. These components, established towards the end of the growing season, are remobilized to support early spring growth. Carbohydrates comprise the bulk of reserve material with late fall increments in free sugars being associated with reductions in starch content. Nitrogenous components undergo significant seasonal fluxes, with free amino acids and soluble proteins reaching maxima during late fall. Asparagine, glutamic acid, serine, ornithine, proline, arginine and aspartic acid all contribute significantly to the storage of nitrogen. Changes in nitrate content are associated with the overwintering process. These observations are indicative of the role that nitrogen plays in the overwintering strategy and regenerative capacity of leafy spurge roots.

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“…After isolation the membranes were incubated in solutions of inorganic salts or salts of organic acids which were held at neutral pH for about 15 min at 2 C. Thylakoids were then either stored at 0 C for 3 hr or rapidly frozen (within a few minutes, cf. 28) to about -25 C, kept at that temperature for 3 to 4 hr, and then thawed in a water bath at 20 C. Subsequently, integrity of the membranes was checked by measuring the activity of cyclic photophosphorylation.…”

Section: Methodsmentioning

confidence: 99%

The Effect of Freezing on Thylakoid Membranes in the Presence of Organic Acids

Santarius¹

1971

Plant Physiol.

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The effect of salts of organic acids on washed and non. washed chloroplast membranes during freezing was investigated. Thylakoids were isolated from spinach leaves (Spinacia oleracea L.) and, prior to freezing, salts of various organic acids or inorganic salts or both were added. Freezing occurred for 3 to 4 hours at -25 C. After thawing membrane integrity was investigated by measuring the activity of cyclic photophosphorylation.At very low NaCi levels (1 to 3 mM, washed thylakoids) salts of organic acids either could not prevent membrane inactivation in the course of freezing (succinate) or were effective only at relatively high concentrations (0.1 M or more of acetate, pyruvate, malate, tartrate, citrate). If NaCl was present at higher concentrations (e.g., 0.1 M) some organic acids, e.g. succinate, malate, tartrate, and citrate, were able to protect frost-sensitive thylakoids at surprisingly low concentrations (10 to 20 mM). Other inorganic salts such as KCI, MgCl2, NaNO3 could also induce protection by organic acids which otherwise were ineffective or poorly effective. For effective protection, a more or less constant ratio between inorganic salt and organic acid or between two or more organic acids had to be maintained. Departure to either side froni the optimal ratio led to progressive inactivation.The unspecificity of the protective effect of organic acids suggests that these compounds protect colligativelv. There are also indications that, in addition, more specific interaction with the membranes contributes to protection. At temperatures above the freezing point, the presence of salts of organic acids decreased the rate of membrane inactivation by hig-h electrolyte concentrations. (6,10,26,27). Therefore, inactivation of biological membranes during freezing seems to be the primary cause of frost damages (5, 21,22).Plants which survive temporary freezing must be able to protect the frost-sensitive membranes during the freezing process. This is achieved during hardening by the synthesis of protective compounds such as sugars (13), sugar alcohols (29), and soluble proteins (4, 6-9, 14, 15, 30). As shown in in vitro experiments, these compounds are able to protect isolated chloroplast and mitochondrial membranes during freezing so that inactivation of photophosphorylation and oxidative phosphorylation does not occur (2, 6-11, 25, 27 (26). In the present paper the effect of organic acids on thylakoid membranes under freezing conditions is subjected to detailed analySiS. MATERIAL AND METHODSMature leaves of spinach (Spinacia oleracea L.) were harvested directly from the field or were bought at the local market.Chloroplasts were isolated in isotonic NaCl as described earlier (10, 27). After isolation they were suspended in distilled water which resulted in osmotic rupture. Freed thylakoids were then used either directly (nonwashed thylakoids) or used after two washings in distilled water to remove stroma proteins and most of the salts, sugars, and amino acids which remained in the chloroplasts during...

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Seasonal changes in soluble protein, nucleic acids, and tissue pH related to cold hardiness of alfalfa

Cited by 38 publications

References 12 publications

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

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

Carbon and nitrogen reserves of leafy spurge (Euphorbia esula) roots as related to overwintering strategy

The Effect of Freezing on Thylakoid Membranes in the Presence of Organic Acids

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