Yiu Jinn-Chin, Liu Cheng-Wei, Fang Denise Yi-Tan, Lai Yu-Shen
Department of Horticulture, National Ilan University, 1, Sec. 1, Shen-Lung Road, I-Lan, 260, Taiwan, Republic of China.
Plant Physiol Biochem. 2009 Aug;47(8):710-6. doi: 10.1016/j.plaphy.2009.03.007. Epub 2009 Mar 28.
Soil flooding is a seasonal factor that negatively affects plant performance and crop yields. In order to investigate the effects of spermidine (Spd) and spermine (Spm) on the waterlogging stress, it was checked that the content of relative water content (RWC), proline, chlorophyll and malondialdehyde (MDA), net photosynthesis, the rate of hydrogen peroxide (H(2)O(2)) and superoxide radicals (O(2)(-)) generation and the antioxidant enzyme activities of superoxide dismutase (SOD) (EC 1.15.1.1), catalase (CAT) (EC 1.11.1.6), ascorbate peroxidase (APX) (EC 1.11.1.11) and glutathione reductase (GR) (EC 1.6.4.2) in Welsh onion (Allium fistulosum L) plants. Pretreatment with 2 mM of Spd and Spm effectively maintained the balance of water content in plant leaves and roots under flooding stress. In addition, the data indicate that the protective role of proline should be considered minimal, as its accumulation was found to be inversely correlated with tolerance to stress; it also significantly retarded the loss of chlorophyll, enhanced photosynthesis, decreased the rate of O(2)(-) generation and H(2)O(2) content, and prevented flooding-induced lipid peroxidation. Spd and Spm helped to maintain antioxidant enzyme activities under flooding; however, APX activity was found to increase slightly in response to Spm. The antioxidant system, an important component of the water-stress-protective mechanism, can be changed by PAs, which are able to moderate the radical scavenging system and to lessen in this way the oxidative stress. The results suggest that pretreatment with Spd and Spm prevents oxidative damage, and the protective effect of Spd was found to be greater than that of Spm.
土壤淹水是一个对植物生长和作物产量产生负面影响的季节性因素。为了研究亚精胺（Spd）和精胺（Spm）对渍水胁迫的影响，检测了大葱（Allium fistulosum L）植株中相对含水量（RWC）、脯氨酸、叶绿素和丙二醛（MDA）的含量、净光合作用、过氧化氢（H₂O₂）和超氧阴离子自由基（O₂⁻）的产生速率以及超氧化物歧化酶（SOD）（EC 1.15.1.1）、过氧化氢酶（CAT）（EC 1.11.1.6）、抗坏血酸过氧化物酶（APX）（EC 1.11.1.11）和谷胱甘肽还原酶（GR）（EC 1.6.4.2）的抗氧化酶活性。用2 mM的Spd和Spm预处理可有效维持淹水胁迫下植物叶片和根系的水分平衡。此外，数据表明脯氨酸的保护作用应被视为最小，因为发现其积累与胁迫耐受性呈负相关；它还显著延缓了叶绿素的损失，增强了光合作用，降低了O₂⁻的产生速率和H₂O₂含量，并防止了淹水诱导的脂质过氧化。Spd和Spm有助于在淹水条件下维持抗氧化酶活性；然而，发现APX活性响应Spm略有增加。抗氧化系统是水分胁迫保护机制的重要组成部分，可被多胺改变，多胺能够调节自由基清除系统并以此减轻氧化胁迫。结果表明，用Spd和Spm预处理可防止氧化损伤，且发现Spd的保护作用大于Spm。
