Temperature and Aging Effects on Leaf Membranes of a Cold Hardy Perennial, Fragaria virginiana

Section of Ecology and Systematics, Cornell University, Ithaca, New York 14850.
Plant physiology (Impact Factor: 6.84). 01/1982; 68(6):1409-15. DOI: 10.1104/pp.68.6.1409
Source: PubMed

ABSTRACT The lipid composition of leaves of wild strawberry (Fragaria virginiana Duchesne) was analyzed throughout an annual growth cycle in the field. Cellular hardiness to temperature stress was assessed concomitantly by a solute leakage technique. Leaves were shown to be very sensitive to an applied temperature of -5 degrees C during the summer months but insensitive to a 35 degrees C treatment. This general pattern was also seen in young overwintering leaves but was reversed after a period of low-temperature hardening of these same leaves. Associated with cold hardening of the overwintering leaves was a twofold increase in the phospholipid content of the leaf membranes with a proportionately smaller increase in free sterols. The large increase in phospholipids presumably is due primarily to the proliferation of a sterol-poor membrane fraction, probably the endoplasmic reticulum. These quantitative changes in membrane material may be important in increasing freezing tolerance in the overwintering leaf cells by enhancing the overall capacity of the cell for plasma membrane and tonoplast extension through vesicle fusion using components from this endomembrane pool. Analysis of electron micrographs of hardened leaf cells showed an increase in vesiculated smooth endoplasmic reticulum and tonoplast membrane over nonhardened leaf cells, the latter resulting in an enhanced tonoplast surface area to vacuolar volume ratio. During this same period, no changes in the fatty acid or free sterol composition were detectable, suggesting that regulation of membrane fluidity via these components is not required for cold acclimation in this species. During aging and senescence of both the overwintering and the summer leaves, the cellular membranes remained functionally intact but became progressively more vulnerable to temperature stress. Free sterol content increased during this time. This feature may be related to the inability of the older leaves to withstand environmental stress. Increasing sensitivity of the cellular membranes to stress may, in turn, be causally related to the actual onset of senescence in these leaves, thus explaining why only the older leaves senesce when the plant is challenged by periodic environmental stress.

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    • "Research on cold temperature damage in strawberry leaves has been conducted on detached leaves or excised leaf disks. Detached leaves sustain significant damage, as assessed by solute leakage, when exposed to temperatures between −5 and −12 • C (O'Neill et al., 1981; Owens et al., 2002). Working with detached leaves does not allow determination of tissue recovery from cold temperature damage. "
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    ABSTRACT: Freezing temperatures are a major limitation to strawberry production in temperate regions, and protected-cultivation strategies such as the use of tunnels and row covers are used to overcome this limitation. In order to optimize management under protected cultivation, it is necessary to understand the damage thresholds for strawberry plant tissues. The effects of freezing temperatures (−3, −5, and −7 °C) on leaf CO2 assimilation were evaluated for ‘Chandler’, ‘Seascape’ and ‘Jewel’ strawberry (Fragaria × ananassa). Growth chambers were used to expose plants to freezing temperatures under carefully defined conditions. Net assimilation was then measured on the cold-exposed leaves after the plants had been returned to 10 °C. Exposure to −3 °C did not significantly reduce CO2 assimilation when compared to plants maintained at 10 °C day/5 °C night. However, leaves exposed to −5 °C for one night had a net CO2 assimilation rate that was 49% of the control. When leaves were first exposed to a conditioning night of −3 °C and then exposed to −5 °C, the net assimilation rate was 62% of the untreated control. Repeated exposure to −5 or −7 °C night temperatures resulted in a further decrease in net assimilation after each successive exposure. Leaves exposed to −7 °C for one night had a net assimilation rate of 6% of the control. Leaves exposed to −5 °C or −7 °C did not show any recovery over a 28-d monitoring period. There was no significant difference among cultivars in the sensitivity of leaves to cold temperatures. These results indicate that protected cultivation systems should be managed to maintain strawberry leaf temperatures above −5 °C in order to preserve full photosynthetic activity of existing leaves which would extend the growing season of the crop.
    Scientia Horticulturae 02/2015; 183. DOI:10.1016/j.scienta.2014.12.001 · 1.37 Impact Factor
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    • "During the first month there was an increase in phospholipid content of the microsomal membranes and no change in sterol content. An enrichment in membrane phospholipid content with increasing cold hardiness has been demonstrated in a wide range of plants (Miller et al., 1974; Raison et al., 1980; O'Neill et al., 1981; Yoshida, 1984). Thus, the phospholipid enrichment in plasma membrane seems to be a general phenomenon related to development of cold hardiness in plants. "
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    ABSTRACT: Apple fruits (Malus sylvestris cultivar ‘Calville de San Sauveur’) were examined during storage at 0°C in air and in a controlled atmosphere for up to 6 months. Their viscosity and the lipid components of the microsomal membrane fraction changed as the storage period progressed. The viscosity decreased at the beginning of storage, and this was correlated with an increase in the amount of phospholipids in the membranes. Phospholipid fatty acids and sterol levels also showed changes during the course of storage. After removal from storage and simulated shelf-life at 20°C for 5 days, the membrane viscosity increased as well as membrane permeability to electrolytes. The membrane phospholipids showed a decrease in the degree of unsaturation of the fatty acids, and there was an increase in the ratio of sterols to phospholipids. It is suggested that primary adaptive change during low-temperature storage is an increase in phospholipid content, while during ripening changes occur in the fatty acid composition of the phospholipids and in the sterol:phospholipid ratio.
    Scientia Horticulturae 06/1987; 32(1-2-32):73-83. DOI:10.1016/0304-4238(87)90018-5 · 1.37 Impact Factor
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    ABSTRACT: The adaptive significance of leaf life spans has been examined from several different points of view. Evergreenness has been explained in terms of nutrient conservation, improving carbon balance, and as a general adapatation to environmental stress. In this review we consider these theories and attempt to synthesise divergent viewpoints. We consider the question "How is the length of a leafs life span related to environmental factoprs?" In particular, what are the comparative advantages of the evergreen and deciduous habits and how can adaptive differences be related to distributional patterns and climatic gradients?
    Annual Review of Ecology and Systematics 11/1982; 13(1):229-259. DOI:10.1146/ · 10.97 Impact Factor
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