Study on cold resistance of three evergreen broad-leaved plants
2017
Na, Wang | Kui-ling, Wang | Qing-hua, Liu | Qing-chao, Liu
In this study, the leaves of three evergreen plants, such as Photinia lasiogyna, Loropetalum chinense var. rubrum Yieh, and Camellia sasanqua Thunb were used as the test materials. Their cold resistance was evaluated comprehensively by making an observation on the changes of soluble sugar, soluble protein, free proline, POD activity, chlorophyll content and relative electric conductivity under simulated low temperature as well as the changes of leaf SPAD, leaf surface feature and section tissue structure during the process of natural wintering. Results showed that (1) During the process of simulated low temperature stress, the chlorophyll content of three species of evergreen plants continuously decreased, relative electric conductivity and the content of soluble sugar tended to increase, soluble protein and free proline contents increased initially and then decreased, and their POD activity continuously rose or rose initially and then fell. (2) The low semi-lethal temperatures (LT50) of P. lasiogyna, L. chinense var. rubrum, C. sasanqua were respectively −15.22°C, −11.88°C, and −22.28°C. (3) During the winter, the leaf SPAD of the three species changed markedly, reflecting that the change of relative chlorophyll content was related to the change of the temperature, and it is advantageous to the enhancement of low temperature adaptation. (4) A series of adaptation of the three species in their leave surface feature and section structure have resulted in cold-resistance higher to some extent such as plasmolysis in mesophyll cell of Photinia lasiogyna, increasing of calcium oxalate crystals in mesophyll cell of Camellia sasanpua Thunb as well as stellate hair in leave surface of Loropetalum chinense var. rubrum Yieh.
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