湖北林业科技

In order to explore the physiological and biochemical response mechanism of C. oleifera seedlings to low temperature stress, this experiment took the 2-year-old seedlings of C. oleifera ‘Changlin 4’ as the experimental material to study the response of its phenotype, leaf gas exchange parameters and related physiological indicators under cold stress (4 ℃ and -4 ℃). The results showed that: ① Cold stress significantly affected the morphological characteristics of C. oleifera ‘Changlin 4’, causing wilting and water loss symptoms of the young stems and leaves in different degrees, and the degree of plant damage was more serious under -4℃ treatment than under 4℃ treatment. ② Cold stress significantly reduced the values of gas exchange parameters (Pn、Gs、Tr、RWUEi) in the leaves of C. oleifera, which continued to decline during the recovery period, and the inhibition effect of -4℃ treatment was significantly stronger than that of 4℃. ③ Although cold stress reduced the SPAD value of C. oleifera, it did not reach a significant level. ④ Cold stress significantly increased the content of MDA, Pro and soluble sugar in the leaves of C. oleifera. During the recovery period, the MDA and Pro content of 4℃ treatment decreased slightly, while the soluble sugar content continued to increase; the MDA and soluble sugar content of -4℃ treatment decreased slightly, while the Pro content continued to increase. ⑤ Cold stress significantly affected the activity of antioxidant enzymes in the leaves of C. oleifera. With the extension of stress time, SOD and POD activities continued to increase, while CAT activities first increased and then decreased, and the increase of -4℃ treatment was significantly higher than that of 4℃; during the recovery period, the activity of antioxidant enzymes decreased in varying degrees.