Relationship between soluble carbohydrates, prolin and ion leakage and Freezing Injury in some almond cultivars at different phenophases of Flower bud development
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Relationship between ion leakage and freezing injury in some peach cultivars A. Imani1 and Z. Moghadam Zeabadi2 1Horticultural Department of Seed and Plant Improvement Institute (SPII), P.O. Box31585-4119 Karaj, Iran 2Horticulture Science Department, Faculty of Agriculture, University of Islamic Azad Abhar 23657, Iran Abstract
Frost damage to the flowers and early developing fruits is one of the most limiting factors in the most peach cultivation regions of the world. This study was undertaken to help understand peach response to frost damage, in order to develop criteria for the selection of cultivars with improved resistance to frost. In this work, 33 peach cultivars on the basis frosts damage and ion leakage was measured. Results showed that the severity of frost damage was influenced by cultivar. Cultivars that had the more resistant to frost damage respectively had less ion leakage. It is suggested that the less ion leakage may serve as indicator of frost tolerance in peach breeding material. Keywords:, ion leakage, freezing injury, peach Introduction: The ecology is a main factor which determines if a fruit tree can be commercially grown in a region. Low temperatures are very important, especially during winter and spring. Low winter temperatures can damage the trees and even kill them .Fruit tree tolerance varies from one species to another (Miranda et al., 2005; Barranco and Natividad, 2005). For example peach (Prunus persica, Batsch) may suffer damage by temperatures below -15 °C or -20 °C in winter, but it is an early blooming species and as a result, Peach cultivation was restricted to regions with low risk of spring frosts(Kester ster and Assay, 1975). Thus, peach breeding aimed to create and select resistant cultivars (Kester and Assay, 1975).Therefore, In peach, to know about the minimum threshold temperature causing damages in flowers and young fruits is very (Richard and Layne, 1992). Cold acclimation is associated with multiple mechanisms which are thought each one to play a role in protection of plant from freezing injury (Lang et al., 1994; Orvar et al., 2000). Frost affects plant cell membranes, which become less permeable and even break, giving rise to the leakage of solute from damaged cells, this electrolyte leakage can be measured in terms of the electrical conductivity (Ec( of the medium (Linden ,2002). Ec measurement is a simple, quick, effective and reproducible way of selecting Peach genotypes by cold hardiness. The major changes in osmotic potential are due to changes in sugars, and there is often a good correlation between sugar content and freezing tolerance (Levitt, 1980). The objectives of this study are: 1) to determine Peach response to frost damage; 2) the relationship between the frosts damage and ion leakage in cultivars.
Plant material Branches with equal length and diameter were harvested from 33 peach cultivars in petal fall stage were placed in a special containers and carried immediately to the laboratory. Branches were taken from all position on the tree. Test freezing For test freezing, branch were spread in to a chamber (432 L;ASLAparatos Cientificos,Madrid Spain). This programmable chamber model is equipped with a heat- cold unit working in -20 to +30 °C range with 0.3 °C precision. 5 thermopar probes connected to a data logger (LI-100; LI-COR, Inc., Lincoln, Neb) were placed near the samples. Air temperature in the chamber was maintained at 5° C for 50 min and then programmed to decline by 2 °C per hour until the desired frost temperature was reached. The frost temperature was maintained for 30 min and was then increased up to 7 °C by 2 °C h-1. frost was applied in the petal fall stage under -3 °C. Frost damage rate was evaluated 24 h after frost treatment. Flower buds were regarded as frost damaged when they showed brownish. Electrolyte leakage (EL) analysis: EL was measured according to Barranco et al. (2005). Square leaf segments (0.5cm2) were excised with a razor blade, washed indeionized water, after which 0.5 g material sample was placed in an Erlenmeyer flask containing 15mL of deionized water. The flasks were then shaken for 24h using aconductancemeter (Consortmodel C831, Turnhout, Belgium) at 120 rpm in light conditions, at an ambient temperature of 20 to 22° C. The initial electrolytic conductivity of each solution (initial Ec, in µS.cm-1) was measured, to obtain an indirect indication of the amount of ion released at each freezing temperature. Sample tubes were then autoclaved (1h, 120° C, 1atm) to kill the tissues completely. After 2 h Shaking at 200 rpm in light conditions, electrical conductivity was measured again (autoclave Ec), to obtain a reference value for total ions. Relative Ec at each temperature (T) was calculated as ECr = (initial Ec/ autoclave Ec) × 100. Statistical analysis: Data were analyzed statistically by ANOVA and factorial design at three replications and means were compared using Duncan’s new multiple range test (DMRT). The statistical software used was MSTAT-C. Results and discussion: Results of excremental showed highly significant differences between cultivars in the relationship with frost damage( Table 1).So that freezing damage in petal fall stage in cultivar Redtop in the temperature -3° C, %95/37 with% 35.3 ion leakage while in petal fall stage and at same temperature, Angiri cultivar %84/4 is damaged with least ion leakage (% 7.5).
Phenological stage and tissue type seems to be important regarding the degree of frost damage, as trees were more affected at full bloom than at the Popcorn (balloon) stage. Miranda et al. (2005) concluded that prunus species resist to frost without major damage before the bloom phase, but is susceptible to frost during and after full blooming. The frost resistance of peach has been recognized for many years, but tolerance and avoidance mechanisms of freezing resistance have not been investigated previously. Results showed that a position correlation was observed between the percentage ion leakage and frost damage for all the cultivars under study (Table 1). According to investigations of Murata and Tatsumi (1979),Hardwick and Anderews( 1980) and Linden (2002), the level of cold tolerance among cultivars of species and the amount of ion leakage in response to stress had been the different. They also concluded that electrolyte leakage, a public property for all species is not sensitive to freeze. In this present study, it was cleared that the electrolyte leakage of peach cultivars flowers in response to freeze stress increased. So this criterion may be used to evaluate sensitivity or resistance cultivars to freeze. Literature Cited Barranco, D and Natividad R.2005. Frost tolerance of eight olive cultivars. Hortscince 40 (3):558-60 Hardwick,R.C and Anderews D.J.1980. A method of measuring differences between varieties in tolerance to suboptimal temperatures.Ann.Apple.Biol.95:235-246. Kester, D.E. and Asay, R.A. 1975. TemperateNuts-Almond, Advances in FruitBreeding (Eds: J.Janick and J.M. Moore) Purdue University Press, West Lafayette,Indiana, 387-419. Lang, V. ,Manty, Welin,A.E. ,Sundberg, B.B., Palva, E.T.1994.Alterations in water status, endogenous abscisic acid of freezing tolerance in Arabidopsis thaliana. Plant Physiol.104:1341-1349. Levitt, J. 1980. Responses of plants to environmental strees .vol 2. 2nd ed. Academic press.London. Linden, L. 2002.Measuring cold hardiness in woody plants.Ph D.Thesis.,Helsinki Univ.Pub. Miranda, C., L.G.Santesteban. and J.B. Royo. 2005. Variability in the relationship between frost temperature and injury level for some cultivated prunus species HortScience 4(2): 357-361. Murata,T. and Tatsumi ,Y. 1979.Ion leakage in chilled plant tissues. In: Low temperature stress in crop plants,the role of the membrane .Academic Press.,New York. Orvar B.L., Sangwan, V., Omann, F., Dhindsa, R.S.2000.Early steps in cold sensing by plant cells; the role of actin cytoskeleton and membrane fluidity. Plant J.23:785-794. Richard, E. and Layne, R.E.C.1992. Breeding cold Hardy Peaches and nectarines.Plant breeding Reviews . 10, .271-308.
1Mean with the same letter are not significantly different at p=0.05using Duncan’s multiple range test Yüklə 50,06 Kb. Dostları ilə paylaş:
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