根系温度对光核桃幼苗光合机构热稳定性的影响

doi:10.3773/j.issn.1005-264x.2009.05.018

摘要/Abstract

摘要：

以光核桃(Prunus mira)幼苗为材料, 通过控制根系温度研究了根系温度变化与叶片脱落酸(ABA)的关系及其对光合机构热稳定性的影响。结果表明: 1)环境高温(37和40 ℃)胁迫下保持根系温度适宜((25±2) ℃)时, 幼苗叶片相对含水量(Relative water content, RWC)下降较少, 但叶片ABA含量低, 超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、过氧化物酶(POD)和过氧化氢酶(CAT)活性低, 过氧化氢(H₂O₂)含量和膜质过氧化水平(丙二醛(Malondialdehyde, MDA)浓度)提高, 最大光化学效率(F_v/F_m)下降程度较大; 2)而同等环境高温(37和40 ℃)条件下根系温度逐步升高时, 幼苗叶片RWC降低, 叶片ABA含量增加, SOD、APX、POD、CAT活性高, H₂O₂含量高, MDA生成量低, F_v/F_m降低程度较小。与37 ℃相比, 40 ℃处理条件下各生理指标变化趋势相似, 但差异加大。因此认为: 高温胁迫条件下, 根系温度适宜时RWC高, 但导致光合机构伤害较重; 根系感受高温胁迫能够增加叶片ABA含量, 有助于保护光合机构、提高光合机构的抗热性。

关键词: 高温胁迫, 抗氧化酶, 过氧化氢, 荧光, 光核桃

Abstract:

Aims High temperature is one of the major abiotic factors that limit plant growth and development in many regions of the world. Although plant thermo-tolerance has been extensively investigated, little attention has been paid to the effects of root temperature on thermo-stability of the photosynthetic apparatus. Our objective was to investigate the effects of variation in root temperature on photosynthetic apparatus and explore potential mechanisms.
Methods Under high air temperature (37 and 40 ℃), root temperatures of Prunus mira seedlings were increased gradually (variable root temperature) or kept at (25±2) ℃ (appropriate root temperature) throughout the treatment. We examined relative water content, H₂O₂concentration, malondialdehyde (MDA) concentration, activity of antioxidant enzymes, cholorophyll a fluorescence and ABA content in leaves. The experimental design was completely randomized, and each treatment was replicated at least three times.
Important findings The combination of high air temperature and appropriate root temperature induced a decrease in activities of antioxidant enzymes and maximum quantum yield of PSII (F_v/F_m) with relatively high leaf relative water content (RWC). Hydrogen peroxide (H₂O₂) and MDA increased, indicating the photosynthetic apparatus was damaged by high temperature. The combination of high air temperature and gradually increasing root temperature reduced damage to the photosynthetic apparatus with significant improvement in antioxidant enzymes activities and leaf ABA content. Therefore, root temperature plays an important role in enhancing the thermo-stability of the photosynthetic apparatus. First, roots at appropriate temperature maintain high relative water content of leaves, but have damaged photosynthetic apparatus. Second, roots sensed the temperature stimulus and increased the leaf ABA accumulation when root temperature increased gradually, and high leaf ABA level prevented damage to the photosynthetic apparatus and enhanced heat-resistance.

Key words: high temperature stress, antioxidant enzyme, H₂O₂, fluorescence, Prunus mira

郝海平, 姜闯道, 石雷, 唐宇丹, 姚涓, 李志强. 根系温度对光核桃幼苗光合机构热稳定性的影响. 植物生态学报, 2009, 33(5): 984-992. DOI: 10.3773/j.issn.1005-264x.2009.05.018

HAO Hai-Ping, JIANG Chuang-Dao, SHI Lei, TANG Yu-Dan, YAO Juan, LI Zhi-Qiang. EFFECTS OF ROOT TEMPERATURE ON THERMOSTABILITY OF PHOTOSYNTHETIC APPARATUS IN PRUNUS MIRA SEEDLINGS. Chinese Journal of Plant Ecology, 2009, 33(5): 984-992. DOI: 10.3773/j.issn.1005-264x.2009.05.018

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https://www.plant-ecology.com/CN/Y2009/V33/I5/984

图/表 6

图1 控温装置示意图根据试验处理, 夹层填充冰袋或干燥珍珠岩 According to the experimental design, ice bag or dry perlite was filled in the temperature control interlayer space

Fig. 1 Sketch map of temperature control container

图2 环境高温(37或40 ℃)条件下光核桃幼苗的根系温度变化对叶片相对含水量(A、B)和丙二醛(MDA)含量 (C、D)的影响(平均值±标准误差, n=3) RTC: 根系控温 Constant root temperature RTI: 根系逐步升温 Root temperature increasing gradually RTC、RTI: 同表1 See Table 1

Fig. 2 Effects of root temperature of Prunus mira seedlings on leaf relative water content (A, B) and Malondialdehyde (MDA) content (C, D) in the leaves of P. mira at high air temperature of 37 or 40 ℃ (mean±SE, n=3)

图3 环境高温(37或40 ℃)条件下光核桃幼苗的根系温度对叶片初始荧光(Fo)(A, B)、最大荧光产量(Fm)(C, D)、光系统Ⅱ最大光化学效率(Fv/Fm) (E, F)的影响(平均值±标准误差, n=6) 单星号表示Duncan’s检验中差异达到0.05显著水平, 双星号表示差异达到0.01显著水平 Values within the same columns with single or double asterisk are significantly different at 0.05 or 0.01 probability level using Duncan’s multiple range test RTC、RTI: 同表1 See Table 1

Fig. 3 Effects of root temperature of Prunus mira seedlings on the initial fluorescence (Fo) (A, B), maximal fluorescence (Fm) (C, D) and maximum quantum yield of PSⅡ photochemistry (Fv/Fm) (E, F) in the leaves of P. mira at 37 ℃ or 40 ℃ (mean±SE, n=6)

图4 环境高温37 ℃ (A、B)和40 ℃ (C、D)处理8 h条件下光核桃幼苗的根系温度对叶片H2O2 (深色部分) 含量的影响 RTC、RTI: 同表1 See Table 1

Fig. 4 Effects of root temperature of Prunus mira seedlings on H2O2 (dark section) concentration in the P. mira leaves at 37 ℃ (A, B) and 40 ℃ (C, D) for 8 h

图5 环境高温(37或40 ℃)条件下光核桃幼苗的根系温度对叶片中SOD、POD、APX、CAT的比活力的影响(平均值±标准误差, n=3) 单星号表示Duncan’s检验中差异达到0.05显著水平, 双星号表示达到0.01显著水平 Values within the same columns with single or double asterisk are significantly different at 0.05 or 0.01 probability level using Duncan’s multiple range test RTC、RTI: 同表1 See Table 1

Fig. 5 Effects of root temperature of Prunus mira seedlings on specific activity of SOD, POD, APX and CAT in P. mira leaves at 37 ℃ or 40 ℃ (mean±SE, n=3)

图6 环境高温(37或40 ℃)条件下光核桃幼苗的根系温度对叶片ABA含量的影响(n=3) RTC、RTI: 同表1 See Table 1

Fig. 6 Effects of root temperature of Prunus mira seedlings on ABA content in P. mira leaves at 37 ℃ or 40 ℃ (n=3)

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