The relationship of upper leaf necrosis with partial physiological traits of three oriental hybrid lily cultivars

The Upper Leaf Necrosis (ULN) of three oriental hybrid lily cultivars appeared on the upper leaves at the 5 th week and developed rapidly the most severe symptoms at the 7 th week after planting in Beijing’s winter. At the 7 th week, the ULN index of ‘Sorbonne ‘, ‘Montezuma’ and ‘Siberia’ were 73.81%, 47.41% and 2.50%, respectively. At the same time, the content of chlorophyll a + b of ‘Sorbonne’ was 19.54% and 6.34% lower than that of ‘Siberia’ and ‘Montezuma’. The average root activity of ‘Sorbonne’ was 22.81% and 10.10% weaker than that of ‘Siberia’ and ‘Montezuma’ during the experimental period. Through comparison with the partial physiological traits among the three different ULN sensitivity cultivars, the correlation coefficients of the ULN index with partial physiological traits of three lily cultivars were analysed at the 7 th week. The result showed the ULN index of three lily cultivars was very significantly negatively correlated with root activity, chlorophyll (a+b), net photosynthesis (Pn) and water use efficiency (WUE) (p<0.01) and was significantly negatively correlated with transpiration (Tr) and significantly positively correlated with transpiration and intercellular concentration of carbonoxide (Ci) (p<0.05). The ULN index of three lily cultivars was not significantly correlated with malondialdehyde (MDA), stomatal conductance (Gs), chlorophyll fluorescence of photosynthetic system II (ΦPsII) and photochemical efficiency of ΦPSII (Fv/Fm). According to the result, root activity, chlorophyll (a+b), Pn and WUE could become rapid screening indicators to evaluate ULN resistances among different lily cultivars in greenhouse in winter. Key word: Upper leaf necrosis, lily, root activity, photosynthesis reference, water use efficiency, correlation analysis.