盐胁迫对彩叶草生长和渗透调节物质积累的影响

用NaCl浓度为0(对照),10,50,100,150,200 mmol/L处理盆栽彩叶草,研究盐胁迫对彩叶草生长、水分状况和渗透调节物质积累的影响。结果显示,与对照相比,随着NaCl浓度增加,彩叶草鲜重、干重、含水量、水势均呈下降趋势,Na⁺、脯氨酸、可溶性糖含量呈上升趋势,K⁺、Ca²⁺、Mg²⁺、NO₃^-含量呈先上升后下降趋势,游离氨基酸含量呈先下降后上升趋势。高效液相色谱结果显示8种有机酸含量的变化幅度也各不相同。综合分析表明,NaCl胁迫对彩叶草生长有抑制作用,且随着盐浓度的增加,其生长受抑制和水分胁迫程度加重;低浓度盐胁迫下,彩叶草通过积累Na⁺、Ca²⁺、Mg²⁺、NO₃^-等无机离子和脯氨酸、可溶性糖、乙醇酸、丙二酸、α-酮戊二酸和柠檬酸等有机渗透调节物质进行调节的;而高浓度盐胁迫下,通过积累Na⁺、脯氨酸、可溶性糖、游离氨基酸、苹果酸、丁二酸、草酸、乙醇酸和丙二酸等渗透调节物质进行调节。因此,在不同浓度盐胁迫下,彩叶草通过改变渗透调节物质种类或积累量适应渗透胁迫。

Effects of salt stress on the growth and osmotica accumulation of Coleus blumei

Potted Coleus blumei plants were treated with NaCl concentrations of 0 (control), 10, 50,100,150,or 200 mmol/L, and the effect of salt stress on growth, water status and osmotica accumulation were studied. Compared with the control, as NaCl concentration increased, the fresh weight, dry weight, water content and water potential decreased, while Na⁺, proline, soluble sugar content showed an upward trend. The contents of K⁺, Ca²⁺, Mg²⁺, NO₃^- were initially increased but then decreased, while free amino acid content showed the opposite trend. The results of high-performance liquid chromatography (HPLC) showed that the change rates of eight organic acids differed from each other. Synthetic analysis indicated that NaCl stress inhibited the growth of C. blumei, and the inhibitory effect on growth and water stress were enhanced as NaCl concentration increased. Under low salinity stress C. blumei accumulated the osmotica of inorganic ions such as Na⁺, Ca²⁺, Mg²⁺, NO₃^- etc, and organic matter such as proline, soluble sugar, ethanol acid, malonic acid, α-ketoglutarate and citric acid to adjust osmotic stress. To adjust osmotic stress at high salinities it accumulated osmotica such as Na⁺, proline, soluble sugar, free amino acid, malic acid, succinic acid, oxalic acid, glycolic acid and malonic acid. Therefore C. blumei accumulated different osmotica to adapt to osmotic stress under different NaCl salinity stresses.