Application of novel image base estimation of invisible leaf injuries in relation to morphological and photosynthetic changes of Phaseolus vulgaris L. exposed to tropospheric ozone

Özet

This study aimed to evaluate the degree of Phaseolus vulgaris L. (bean) leaf tissue injury caused bytropospheric ozone. To validate O3 symptoms at the microscopic level, Evans blue staining together withan image processing method for the removal of distortions and calculation of dead leaf areas was applied.Net photosynthetic rate (PN), stomatal conductance (gs) and intercellular CO2 concentration (Ci) weredetermined to evaluate leaf physiological responses to ozone. It was found that both resistant andsensitive varieties of bean were damaged by ozone; however, the size of necrotic and partially destroyedleaf area in the sensitive genotype (S156) was bigger (1.18%, 2.18%) than in the resistant genotype (R123),i.e. 0.02% and 0.50%. Values of net photosynthetic rates were lower in the sensitive genotype in ambientair conditions, than in the resistant genotype in ambient air conditions. We further found that there wasa correlation between physiological and anatomical injuries; net photosynthetic rate (PN) was negativelycorrelated with percentage of necrotic area of both genotypes, while stomatal conductance (gs), intercellularCO2 concentration (Ci) were positively correlated with percentage of necrotic tissue of bothgenotypes. Moreover, visible injures in both genotypes were positively correlated with percentage ofanatomical injures. In conclusion, the presented combinations of morphological, anatomical and physiologicalmarkers allowed differential diagnosis of ozone injury.