内生枯草芽孢杆菌265ZY4对温度和紫外光胁迫下紫花针茅生化特征的影响

在高、低温和紫外线胁迫下,将高寒草地紫花针茅的内生细菌265ZY4回接至紫花针茅测定其对寄主抗胁迫能力的影响。结果表明,接种265ZY4后紫花针茅的株高增加35.02%,叶宽增加34.69%;在低温、高温和紫外线胁迫下带菌紫花针茅叶绿素含量高于对照,温度胁迫下叶绿素呈先上升后下降,但紫外线胁迫下呈快速下降;在低温和紫外线胁迫下带菌紫花针茅可溶性糖含量分别在第4和6天后显著高于对照,但可溶性蛋白含量低于对照,温度和紫外线胁迫下可溶性蛋白和可溶性糖呈“上升-下降”的趋势;低温胁迫下带菌紫花针茅超氧化物歧化酶(SOD)活性变化显著小于对照,带菌及对照均呈“降低-升高-降低”的规律;紫外线胁迫下带菌植株SOD活性呈现“下降-上升”的趋势,第8天时显著高于对照,对照表现为“下降-上升-下降”的趋势;在低温和紫外线胁迫下带菌紫花针茅苯丙氨酸解氨酶(PAL)活性高于对照,且在低温胁迫下呈“上升-下降”的趋势,但在高温和紫外线胁迫下呈“下降-上升-下降”的趋势。试验结果表明,内生细菌265ZY4有助于维持逆境胁迫下宿主生化指标的稳定,提高宿主对逆境的忍耐能力。

Effects of endophytic Bacillus subtilis 265ZY4 on physiological and biochemical characteristics of Stipa purpurea under abiotic stress

In order to understand the effects of the endophytic bacterium, Bacillus subtilis, on Stipa purpurea under high temperature, low temperature and ultraviolet stress, the biochemical characteristics of S. purpurea inoculated with B. subtilis strain 265ZY4 were compared with those of plants not carrying the bacterial endophyte. The results showed that the height and leaf width of S. purpurea with 265ZY4 were 35.02% and 34.69%, respectively, more than in the control plants. When S. purpurea was subject to high- or low-temperature stress, leaf chlorophyll content rose and then fell. Under ultraviolet stress, chlorophyll levels dropped rapidly, but the chlorophyll content of S. purpurea with 265ZY4 remained higher than those in the control. The soluble protein and soluble sugar levels also initially rose and then dropped under abiotic stress, but the soluble sugar levels of S. purpurea with 265ZY4 were distinctly higher than those in the control plants after 4 and 6 days. The superoxide dismutase (SOD) activity displayed a decrease-increase-decrease curve with progressive increase in high- and low-temperature stress, but the SOD activity of S. purpurea with 265ZY4 was more stable. The SOD activity of the control plants showed a decrease-increase-decrease curve pattern under increasing ultraviolet exposure, but the activity of S. purpurea with 265ZY4 showed a curve pattern that differed from the control plants. The phenylalnine ammonialyase (PAL) activity displayed an increase-decrease curve pattern under low temperature stress and a decrease-increase-decrease curve under high temperature and ultraviolet stress, but the PAL activities of S. purpurea plants with 265ZY4 were distinctly higher than those in the control. In summary, the results show that the endophytic B. subtilis strain 265ZY4 is beneficial to S. pupurea through assisting with maintenance of chlorophyll, soluble protein, and soluble sugar levels, and SOD and PAL activities, and reducing the range of metabolic variability under the abiotic stress factors tested, thus indicating enhancement of S. purpurea stress tolerance ability.