Acta Horticulturae · 2010 · 16 citations · 0 references
AgriculturePlant BiologyPlant SciencesPlant EcophysiologyPlant PhysiologyPostharvest PhysiologyAbiotic Stress EvaluationCold HardinessCold Stress PhysiologyPhysiological Screening For Stress ToleranceStomatal PhysiologyStress Tolerance ScreeningCold Hardiness BiomarkersCold Hardiness PhenotypingCold Stress Effects On StomataFreezingFreezing Onset TemperatureStomatal Conductance MonitoringStomatal Density AnalysisStomatal Index
In this work, leaf samples of one-year-old walnut cultivars and elite genotypes including 'Serr', 'Lara', 'Pedro', 'Hartley', 'Z 30 ', 'Z 63 ', 'Z 67 ' and 'Z 53 ' were taken and exposed to cold temperature at the rate of drop of 4°C per h at 0, -4, -8, -12 and -16°C. The lethal freezing temperature (LT 50 ) of cultivars and genotypes was evaluated by electrolyte leakage studies and the cultivars/genotypes were grouped into hardy, semi-hardy and non-hardy using this method. The density of stomata in the leaves of cultivars and elite genotypes rated as hardy were significantly lower than those rated as semi-hardy and non-hardy. Stomatal density of the cultivars and genotypes in the intermediate class fell within the range of hardy and non-hardy cultivars and genotypes. According to these results, number of stomata could be considered as a simple and effective anatomical selection marker for screening walnut plants for cold hardiness.