Subjects: Biology >> Botany >> Applied botany submitted time 2019-08-26 Cooperative journals: 《广西植物》
Abstract： In order to explore the tolerance and reaction mechanism of Handroanthus chrysotrichus towards coldness, 1 a seedlings of H. chrysotrichus were put under artificially controlling low temperature treatments. Physiological indexes and chlorophyll fluorescence parameters were measured. The result shows that under low temperature stress of 6 ℃ or above, seeldings can improve their cold tolerance and protect themselves by enhancing SOD activity, SS contents and Pro contents. In addition, seedlings can also prevent their photosynthetic system from cold damaging through improving NPQ. When the temperature reaches to 2 ℃, both PSⅡreaction center and photosynthetic system will be badly damaged. From these changes, we deduce that seedlings of H. chrysotrichus can resist to low temperature ranging 2-5 ℃ and prevent the meselves from coldness through self-adjustment. However, the critical point still needs to be determined. Our paper also finds out that when facing low temperature 6 ℃ or above, SS contents rapidly rise up. When the temperature reaches to 2 ℃ or below, Pro contents remarkably rise up. Perhaps seedlings of H. chrysotrichus can protect themselves from low temperature 6 ℃ or above by enhancing SOD activities and SS contents. Seedlings of H. chrysotrichus will mitigate damages of low temperature 2 ℃ or below by enhancing SOD activities and Pro contents. It is concluded that the seedlings of H. chrysotrichus could not resist the freezing damage caused by low temperature below 0 ℃, but have certain tolerance to low temperature above 0 ℃. The results are beneficial to both selecting resistent varieties and promoting cultivation. It is also good for exploring cold tolerant ability of plants.
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