低温胁迫对不同甘蔗品种叶片光合色素和光合生理特性的影响

以4个抗寒能力不同的甘蔗品种(系)作为研究材料,分析光合色素含量与构成以及采用叶绿素荧光成像技术探究低温对甘蔗光合生理特性的影响。结果表明:耐寒性强的GR2、GT28叶片单位面积叶绿素a含量分别比ROC22高13.74%、10.39%,其叶片F_v'/F_m'分别高3.25%、3.01%,且这差异随着胁迫时间延长逐渐明显,而Φ_psⅡ和qP也具有相同的变化趋势;GR2、GT28叶片的单位面积类胡萝卜素含量分别比ROC22高22.73%、19.36%,其叶片NPQ分别高20.33%、12.17%,且NPQ随着胁迫延长快速升高;甘蔗在早期响应阶段(0～24 h)单位叶面积的光合色素含量基本不变,而叶片的F_v'/F_m'、Φ_psⅡ和qP受到抑制却迅速降低后并维持相对稳定,相反NPQ急速升高;在胁迫适应阶段(24～168h),叶片光合色素因为低温造成的合成受阻及结构破坏,其叶片F_v'/F_m'、Φ_psⅡ和qP在(24～72 h)处理期间再次大幅降低,但在(72～168 h)处理阶段光能吸收、利用及耗散份额保持相对平稳,而NPQ先急剧升高后逐渐趋于平缓,说明低温胁迫下甘蔗通过调节光合色素含量及在PSⅠ和PSⅡ的反应中心复合体的结合比例以加快耗散过剩的激发能,是植物(作物)在低温逆境条件其光合机构对光能吸收及利用的调节也是一种重要的保护策略。

Effects of Chilling on Photosynthesis and Photosynthetic Pigment Contents in Leaves of Different Sugarcane Varieties

Using four sugarcane varieties (lines) with different cold resistance as the materials, the research analyzed the content and composition of the photosynthetic pigments in the leaves and used the chlorophyll fluorescence imaging to explore the influence of low temperature on the photosynthetic physiological characteristics in sugarcane. The content of chlorophyll of GR2 and GT28 per unit area was 13.74% and 10.39% higher than that of ROC22 respectively. The F_v'/F_m' was 3.25% and 3.01% higher, respectively, and the difference gradually increased with the prolongation of stress time, and Φ_psII and qP also had the same trends. The carotenoid content per unit area was 22.73% and 19.36% higher, NPQ was 20.33% and 12.17% higher in GR2 and GT28 than that of ROC22, respectively, and NPQ also increased rapidly with the extension of stress. The photosynthetic pigment content per unit leaf area of sugarcane at the early response stage (0-24 h) and the content of photosynthetic pigment per unit leaf area was basically unchanged, but Fv'/Fm', Φ_psII and qP in the leaf were inhibited, showing a rapid decrease and then relatively stable, while NPQ increased rapidly. At the adaptation stage (24-168 h), the leaf photosynthetic pigments were structurally destroyed due to low temperature stress, and F_v'/F_m', Φ_psII and qP were significantly reduced during 24-72 h since the treatment. However, at the treatment stage (72-168 h), the absorption, utilization and dissipation fractions of light energy were relatively stable, while NPQ increased sharply and then gradually became stabilized. The results indicated that under low temperature stress, sugarcane regulated the content of photosynthetic pigment and the combination ratio of PSI and PSII reaction center complexes to accelerate the dissipation of excessive excitation energy, adjusting the absorption of light energy by the photosynthetic apparatus, which was the adjustment on the absorption and utilization of light energy made by the photosynthetic apparatus under low temperature stress conditions and it was considered to be an important protection strategy of plants.