Frost tolerance

Figure 1.2 Origin of S. x ajanhuiri, S. xJuzepczukii and S. x curtilobum cultivated species with bitter taste and frost tolerance.

Phenolic compounds may be involved in plant responses to cold stress and in plant acclimation to low temperature. Acclimation of apple trees to cold climates was found to be associated with a seasonal accumulation of chlorogenic acid [102]. Strengthened frost tolerance in a variety of plants were attributed to thicker cell-wall lignification or suberization [102]. Thickening of cell walls and increased production of suberin-type lipids were observed in cold-acclimated winter rye leaves [103]. The presence of suberin in cell walls may favour membrane cell-wall adhesion, a major factor in the resistance of plant cells to freezing [104]. 

Freezing injury (all plants) increased frost tolerance... 

Robertson, A.J., Gusta, L.V., Reaney, M.J.T. Ishikawa, M. (1987). Protein synthesis in bromegrass (Bromus inermis Leyss) cultured cells during the induction of frost tolerance by abscisic acid or low temperature. Plant Physiology 84, 1331-6. 

Swaaij, van A.C., Jacobsen, E. Feenstra, W.J. (1985). Effect of cold hardening, wilting and exogenously applied proline on leaf proline content and frost tolerance of several genotypes of Solanum. Physio-logia Plantarum 64, 230-6. 

Furthermore, leaves of winter rye have to develop at low temperatures in order to acquire increased resistance to photoinhibition. However, spinach, which has a very much bwer frost tolerance than winter rye, is reported to acquire increased resistance to photoinhibition during cold acclimation (4). Whether the different results obtained with winter rye and spinach, with respect of cold hardening induced resistance to photoinhibition, depend on different developmental strategies of the two species can not be said at present. In Chlamydomonas reinhardtii(5), however, an increased resistance to photoinhibition upon cold acclimation occurred in a culture of dividing and growing cells, which is a similar developmental strategy as that of winter rye. 

Cycocel has been shown to increase the frost tolerance of winter wheat [19], winter rape [14], alfalfa [16], cabbage [15], potato [3] and box elder [12]. In several studies, Cycocel was only effective when applied under hardening conditions, whereas a measurable degree of hardiness under non-hardening conditions has been reported for box elder [12] and winter wheat [19]. 

Sikorska, E. and Kacperska-Palacz, A. (1980) Phospholipid involvement in frost tolerance. Physiol. Plant. 48, 201-206. 

I. Horvath, L. Vigh and T. Farkas - The manipulation of polar head group composition of phospholipids in the wheat Miranovskaja 808 affects frost tolerance. Planta, ]3 h 103-108 (1981). 

The primary breeding objectives for winter HEAR cnltivars are to increase seed yield, increase oil production, improve meal qnaUty, increase erucic add concentration, improve disease resistance and, for the winter habit types, improve winter hardiness and frost tolerance (Downey and Rdbbelen, 1989). The objectives for breeding spring HEAR cultivars are similar. Improved weed control via development of herbicide-tolerant HEAR cnltivars is also a major breeding... 

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