《植物生理学报》 2014, 50(3): 338-346

甘薯幼苗对NaCl胁迫的生理响应及外源钙的缓解效应

王刚¹, 肖强¹, 衣艳君¹, 杨洪兵¹, 史衍玺², 刘家尧^1,*

青岛农业大学1生命科学学院, 山东省高校植物生物技术重点实验室; 2资源与环境学院, 山东青岛266109

通信作者：刘家尧；E-mail: qdliujiayao@163.com；Tel: 0532-86080631

摘　要：

以甘薯品种‘徐薯22’为试验材料, 研究了不同浓度NaCl胁迫对甘薯幼苗生根、叶片抗氧化能力、渗调物质含量、光合气体交换参数、荧光参数及叶片离子含量的影响及不同浓度Ca2+处理对300 mmol·L^-1 NaCl胁迫的缓解效应。结果表明, 低浓度NaCl (50和100 mmol·L^-1)胁迫对甘薯幼苗生根及叶片相对电导率和MDA含量影响较小, 随着盐度的增加, 叶片SOD活性呈先增加后降低趋势, 脯氨酸和可溶性糖含量持续增加, 叶片P_n、T_r、G_s、F_v/F_m、RC/CS₀、TR₀/CS₀、ET₀/CS₀、ΦE₀及K⁺、Ca²⁺含量、K⁺/Na⁺不断降低, ΦD₀和Na⁺含量升高; 高浓度NaCl (300 mmol·L^-1)胁迫下, 甘薯幼苗的正常生理代谢受到显著抑制。适当浓度外源Ca2+能显著缓解NaCl胁迫对甘薯幼苗的毒害作用, 能促进盐胁迫下甘薯幼苗生根, 改善细胞的渗透平衡, 提高渗透调节能力, 降低膜脂过氧化程度, 使甘薯叶片维持较高的F_v/F_m、RC/CS₀、TR₀/CS₀、ET₀/CS₀、ΦE₀和较低的ΦD₀, 增强光合作用和气孔蒸腾作用效率, 说明外施Ca²⁺是提高甘薯耐盐性的一种有效方法。

关键词：缓解效应; 钙; NaCl胁迫; 甘薯

收稿：2013-06-03   修定：2014-01-14

资助：国家甘薯产业技术体系甘薯营养与栽培生理岗位(CARS-11-B-14)、国家自然科学基金(31270314)和青岛农业大学人才基金(630743)。

Alleviatory Function of Exogenous Calcium in Responses of Sweet Potato (Ipomoea batatas Lam.) Seedlings to NaCl Stress

WANG Gang1, XIAO Qiang1, YI Yan-Jun1, YANG Hong-Bing1, SHI Yan-Xi2, LIU Jia-Yao1,*

1College of Life Sciences, Key Lab of Plant Biotechnology in Universities of Shandong; 2College of Resource and Environment, Qingdao Agricultural University, Qingdao, Shandong 266109, China

Corresponding author: LIU Jia-Yao; E-mail: qdliujiayao@163.com; Tel: 0532-86080631

Abstract:

The sweet potato (Ipomoea batatas Lam.) variety ‘Xushu 22’ was used in this study. The effects of different concentration of NaCl on seedling root growth, leaf antioxidant capacity, osmotic adjustment substance content, photosynthetic gas exchange parameters, fluorescence parameters, ion content of leaves, and the alleviatory effect of different concentrations of Ca2+ on 300 mmol·L-1 NaCl stress were analyzed. The results showed that the seedling root growth, the relative conductivity and MDA content of leaves were less affected under low concentrations (50 and 100 mmol·L-1) of NaCl. With the increasing of salinity, the superoxide dismutase (SOD) activity was increased firstly and decreased thereafter, the proline and soluble sugar contents increased, the Pn, Tr, Gs, Fv/Fm, RC/CS0, TR0/CS0, ET0/CS0 and ΦE0 of leaves decreased, while the ΦD0 of leaves increased. The leaf Na+ content was increased, but the K+, Ca2+ and K+/Na+ decreased. Under high concentration (300 mmol·L-1) of NaCl, the sweet potato seedling motebolism was significantly inhibited. Interestingly, it was found that application of appropriate exogenous Ca2+ could significantly abate the poison of NaCl stress in sweet potato seedlings, and 12 mmol·L-1 Ca2+ had the best abating effect, which significantly promoted the root growth, osmoregulation ability of sweet potato seedlings, reduced the membrane lipid oxidation, and kept higher values of Fv/Fm, RC/CS0, TR0/CS0, ET0/CS0, ΦE0 but lower ΦD0 in sweet potato leaves under salt stress. In turn, photosynthesis and transpiration were improved. These observations suggested that the application of exogenous Ca2+ was an effective method to improve the salt tolerance of sweet potato.

Key words: alleviatory effects; calcium; NaCl stress; Ipomoea batatas