作 者 ：胡小婉 刘兆普 郑青松 隆小华 高秀美 刘金隆
期 刊 ：植物营养与肥料学报 2012年 18卷 4期 页码：932-940
Keywords:canola, seedling, Cl- treatment, growth, photosynthetic trait, stomatal limitation,
摘 要 ：采用盆栽砂培试验，研究了不同浓度氯离子（Cl-）处理对油菜（Brassica napus L.）幼苗干物质积累速率（DMAR）、根冠比（R/S）、叶绿素（Chl）含量、氯离子含量（Cl-）、净光合速率（Pn）、气孔导度（Gs）、细胞间CO2浓度（Ci）、蒸腾速率（Tr）、水分利用效率（WUE）、气孔限制值（Ls）等的影响。结果表明：25～100 mmol/L Cl- 处理9 d和18 d，油菜幼苗植株DMAR均上升，均在50 mmol/L Cl- 处理时达到最大值；不同浓度Cl- 处理9 d，Chl含量有先上升后下降的趋势，在100 mmol/L Cl- 处理时达到最大值，处理18 d，Chl含量依次下降。Cl- 处理能显著提高叶片中的Cl- 含量。除了在处理18 d后的Ci外，25～100 mmol/L Cl- 处理下，油菜叶片均能维持较高的Pn、Gs、Ci和Tr，200 mmol/L Cl- 处理9 d和18 d，油菜叶片Pn、Gs、Ci和Tr均显著下降。随着Cl- 浓度的增加，WUE呈现先降后升，在9 d处理后，随着Cl- 浓度的增加，油菜Ls也呈现先升后降，而在18 d处理后，随着Cl- 浓度的增加，Ls逐渐显著上升。上述结果表明，外施低量氯（Cl- 25~100 mmol/L）显著提高或者维持油菜幼苗的光合作用和蒸腾作用，促进油菜幼苗的生长；而高氯（200 mmol/L Cl-）条件下显著降低其光合作用和蒸腾作用，抑制其生长，且抑制油菜幼苗光合的主要是气孔因素。相关性分析还表明，植株DMAR、Pn、Ci、Tr、Gs之间均有显著的正相关性，而Pn与WUE之间存在极显著的负相关。
Abstract:Soil salinization not only is a serious environmental problem but also poses a severe threat to plant growth and agricultural production. The ions of Na+ and Cl- are mainly responsible for salinization. People generally pay close attention to study the Na+ effects on grow, productivity and quality of crop plant, however, relatively much less studies are on Cl- effects on crop plant. The effects of different concentrations of Cl- (0, 25, 50, 75, 100 and 200 mmol/L) on plant growth, photosynthetic pigment, photosynthesis traits and water use efficiency in canola (Brassica napus L.) seedlings for 9 and 18 days were investigated. The results show that the dry matter accumulation rates are increased under the 25-100 mmol/L Cl- treatments for 9 and 18 d, and the highest values are under the treatment of 50 mmol/L Cl-, while the plant dry matter accumulation rate is decreased significantly under the 200 mmol/L Cl-. The chlorophyll (Chl) contents are ascended in first and descended under different concentrations of Cl- treatment for 9 d, and the highest values are under the treatments of 100 mmol/L Cl-. Nevertheless, for 18 d, the Chl contents are decreased under the Cl- treatments, and the more the applied Cl- concentration is, the more the decrease is. The chloride concentrations of canola leaves are markedly increased under the Cl- treatments. Compared with the control, the Cl- contents in canola leaves are increased by 814%, 805%, 1043%, 1083% and 2157% for 9 d and by 745%, 1270%, 1340%, 1900 and 3386% for 18 d, under 25, 50, 75, 100 and 200 mmol/L Cl- treatments, respectively. Apart from Ci under the Cl- treatments for 18 d, canola leaves are able to maintain high values of Pn, Gs, Ci, and Tr under 25-100 mmol/L Cl- treatments. For 9 and 18 d, Pn both achieve the highest values under the 25 mmol/L Cl- treatment, and are increased by 12% and 13% compared with each control, respectively. Pn, Gs, Ci and Tr of canola leaves are significantly decreased under the 200 mmol/L Cl- treatment for 9 and 18 d. As Cl- concentration increased, WUE is descended in first and ascended followed. However, Ls is descended in first and ascended followed under the Cl- treatments for 9 d, and increased gradually for 18 d. Under 200 mmol/L Cl-, Ls of canola leaves are increased by 48 % for 9 d, and by 76 % for 18 d. Correlation analysis indicates that for the 9 d treatments, the DMAR of canola is insignificantly related to root/shoot, Chl content, Cl- content and Ls, very negatively related to WUE, positively related to Gs, and very positively related to Pn, Ci and Tr, respectively. For 18 d treatment, the DMAR of canola is insignificantly related to root/shoot, Chl content, Cl- content, Ls and WUE, positively related to Gs, and very positively related to Pn, and Tr, respectively. Our results implicate that photosynthesis and transpiration of canola seedlings are significantly increased under the low Cl- treatments, and thus make a contribution to plant growth, while the high Cl- treatments show opposite situations, and the photosynthetic limitation is mostly due to stomatal limitation. Pn, Gs and Tr can be regarded as value indexes of chloride adaptation of canola growth.
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