Xu Nan, Sun Guang-Yu
College of Life Science, Northeast Forestry University, Harbin 150040, China.
Ying Yong Sheng Tai Xue Bao. 2009 Apr;20(4):761-6.
Taking the seedlings of mulberry (Morus alba) variety 'Qiuyu' as test materials, this paper studied the changes of their leaf photosynthesis and antioxidant enzymes during low-temperature acclimation, chilling stress, and normal temperature recovery. The results showed that low-temperature acclimation at 12 degrees C for 3 days markedly increased the cold resistance of mulberry seedlings. After the acclimation, the leaf net photosynthetic rate (P(n)), stomatal conductance (G(s)), and maximum photochemical efficiency of photosystem II (F(v)/F(m)) under the chilling stress at 3 degrees C for 3 days increased obviously and recovered rapidly, compared with the control non-acclimation. During the period of the low-temperature acclimation and chilling stress, the leaf proline and soluble sugar contents increased. After the acclimation, the leaf malondialdehyde (MDA) content was obviously lower while the leaf ascorbate peroxidase (APX) activity was obviously higher than the control, illustrating that the increase of osmolytes content and APX activity played important roles in the cold resistance of mulberry seedlings.
以桑树品种‘秋玉’幼苗为试验材料，研究了其在低温驯化、冷胁迫及常温恢复过程中叶光合作用和抗氧化酶的变化。结果表明，12℃低温驯化3天显著提高了桑树幼苗的抗寒性。驯化后，与未驯化的对照相比，在3℃冷胁迫3天条件下，叶片净光合速率（P(n)）、气孔导度（G(s)）和光系统II最大光化学效率（F(v)/F(m)）明显增加且恢复迅速。在低温驯化和冷胁迫期间，叶片脯氨酸和可溶性糖含量增加。驯化后，叶片丙二醛（MDA）含量明显低于对照，而叶片抗坏血酸过氧化物酶（APX）活性明显高于对照，说明渗透调节物质含量和APX活性的增加对桑树幼苗抗寒性起重要作用。
