Abstract:

【Objective】 Several correlations between the changes of carotenoid content and the tolerance of pepper seedlings under low light or low light with low temperature stress were studied. The objective of this study is to screen suitable indexes for evaluating low light- tolerance or chilling- and low light-tolerance of pepper seedlings.【Method】The correlations between the carotenoid content at different times and the tolerance of 12 pepper varieties (expressed as the averaged subordinate function values) under low light or low light with low temperature stress were studied by using correlation analysis. 【Result】 The carotenoid contents in pepper leaves decreased both under 28℃/18℃, 100 μmol?m-2?s-1 PFD stress and under 15℃/5℃, 100 μmol?m-2?s-1 PFD stress, and the carotenoid contents were more smaller in pepper leaves treated under low light with low temperature stress than in those treated under only low light stress. There were strong positive correlations between the averaged subordinate function values and the carotenoid contents in pepper leaves treated under 28℃/18℃, 100 μmol?m-2?s-1 PFD stress for 5, 10, 15, and 20 days. Significant negative correlations existed between the averaged subordinate function values and the carotenoid contents in pepper leaves treated under 15℃/5℃, 100 μmol?m-2?s-1 PFD stress for 10, 15, and 20 days. 【Conclusion】 It was suggested that carotenoid content in pepper leaves treated under 28℃/18℃, 100 μmol?m-2?s-1 PFD stress for 5, 10, 15, and 20 days or 15℃/5℃, 100 μmol?m-2?s-1 PFD stress for 10, 15, and 20 days could be used as good indicators for identification and screening low light- tolerant or chilling- and low light- tolerant pepper varieties. The higher the carotenoid content, the higher tolerance to low light stress. On the contrary, the higher the carotenoid content, the lower tolerance to low light with low temperature stress.

Key words: pepper, carotenoid, low light, low light with low temperature, low-light-tolerance, chilling- and low-light-tolerance