Involvement of Abscisic Acid in Potato Cold Acclimation

Abstract

The possible significance of specific biochemical changes in relation to cold acclimation has been discussed extensively (13), but causal relationship between metabolic changes and cold acclimation is difficult to establish. Generally, the development of frost hardiness has been reported to be accompanied with changes in hormones (12,19,24), and in quality and quantity of proteins (14,16). Under a low temperature regime, an increase in leaf soluble protein content was observed only in those potato species which are able to acclimate, i.e. Solanum acaule and Sc4 (4). The net increase in soluble proteins was significantly and positively correlated with the increase of frost hardiness in these species (4). Potato stem cuttings can be easily rooted and propagated in a nutrient agar medium. Such 'stem-cultured plants' can be acclimated to similar frost hardiness levels as with normal tuberpropagated plants grown in pots (5). ABA could substitute for low temperature treatment in inducing frost hardiness in stem-cultured Sc plants, and GA did not affect the cold acclimation (5).The following is a report of experimental results in attempting to determine if there is a relationship between ABA changes and protein synthesis during the development of frost hardiness in the potato during cold acclimation. MATERIALS AND METHODSPlant Materials. Solanum tuberosum L. cv 'Red Pontiac' was propagated from seed tubers, whereas Solanum commersonii (Oka 5040) was propagated from stem cuttings. Plants were planted in 15-cm diameter pots each in a mixture of soil, sand, and peat (3:2:2, v/v). Plants of both species were grown in a uniform environmental chamber for 2 months in a regime of 14-h photoperiod with 450 ,uEm-2 s-' PAR and 20/15°C D/N temperature. Plants of each species were then divided into two groups. One group (controls) was maintained in the same chamber. The second group (treated) was exposed to low temperature of 2°C D/N with a 14-h photoperiod. Frost hardiness of fully expanded leaves was determined after 0, 1, 2, 3, 4, 5, 10, and 15 d of treatments. At the same time, samples were also collected for chemical analyses and moisture determination. The conditions for propagating and growing stem cultures of St and Sc plants were similar to an earlier report (5).Frost Hardiness Evaluation. Excised leaflets or whole shoots (stem-cultured plants) were subjected to controlled freezing (5). After freezing, leaf tissues were placed over ice in a moisturesaturated box in a 5C room and thawed overnight, followed by warming to room temperature. Viability of the tissues after freezing tests was estimated by the conductivity method (20

Mercuric Chloride Effects on Root Water Transport in Aspen Seedlings

“…Low soil temperatures are known to inhibit L p and induce stomatal closure in aspen (Wan et al, 1999). It is possible that, like low root temperature (Chen et al, 1983;Lee et al, 1993) and drought (Zhang et al, 1987;Lång et al, 1994), HgCl 2 treatment triggered ABA synthesis, which directly caused stomatal closure. This could explain the slow recovery of stomatal opening following ME treatment.…”

Advances in physiological and molecular aspects of plant cold tolerance

“…Through the cold acclimation process, reprogramming of gene expression and various modifications in the metabolism take place (Chinnusamy et al 2010). Acclimation also causes an increase in the production of antioxidants, abscisic acid (ABA) and compatible osmolytes such as soluble sugars and proline (Lynch & Steponkus 1987;Koster & Lynch 1992;Chen et al 1993;Kishitani et al 1994;Uemura & Steponkus 1994;Murelli et al 1995;Nomura et al 1995;Dörffling et al 1997;Tao et al 1998). Denesik (2007) reported that cold treatment affects membrane fluidity resulting in an increase in the membrane rigidity.…”

Development of freezing tolerance in different altitudinal ecotypes of Salix paraplesia

“…In general, there were parallel changes between the ABA contents and freezing tolerance development. Several types of evidence have suggested that ABA-controlled processes are central to cold acclimation and development of freezing tolerance in herbaceous plants, i.e., the low temperature stimulus can be substituted by exogenous ABA, resulting in an increase in freezing tolerance at normal growth temperatures (Chen et al 1983, Lång et al 1989, Mäntylä et al 1995, Tamminen et al 2001; endogenous ABA contents can be enhanced by LT both in chilling-sensitive (Daie andCampbell 1981, Pan 1990), chilling-tolerant annual (Chen et al 1983, Guy andHaskell 1988), and overwintering (Lalk and Dörffling 1985) species. In our study, there were corresponding differences between the ecotypes in ABA alterations during cold acclimation: compared with the low altitudinal ecotype, ABA contents of the high altitudinal ecotype was more responsive to SD and LT.…”