吲哚乙酸对铝胁迫下栝楼生理响应及DNA损伤的缓解作用

为探究IAA(吲哚乙酸)对铝胁迫下栝楼生理响应及DNA损伤的缓解,本研究以河北安国栝楼(耐铝品种)和浙江浦阳栝楼(铝敏感品种)为材料进行水培试验,研究300、800 μmol·L^-1(分别用Al₃₀₀和Al₈₀₀表示)铝环境下不同浓度IAA(0、10、25、50、75 μmol·L^-1,分别以I₀、I₁₀、I₂₅、I₅₀和I₇₅表示)对2个栝楼品种的抗氧化酶活性、丙二醛(MDA)、光合特性、根系活力、叶绿素含量和DNA损伤的影响。结果表明: 与对照相比,铝胁迫条件下,安国和浦阳品种栝楼的超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性、光合作用能力、根系活力等生理指标受到不同程度的抑制,MDA含量明显升高,DNA损伤加重。铝胁迫条件下,与无IAA喷施相比,10～50 μmol·L^-1IAA作用下安国和浦阳栝楼的SOD、CAT和POD酶活性最大增幅分别为15.0%、31.2%、72.3%和13.8%、26.9%、26.4%,叶绿素含量显著增加49.9%和17.9%,MDA积累量减少39.2%和22.4%,荧光参数得到明显改善。25 μmol·L^-1IAA使安国和浦阳栝楼根系活力显著增加159.1%和90.9%,50 μmol·L^-1IAA可有效减缓2个品种栝楼根系DNA拖尾现象,尾部 DNA 百分含量与尾部距离的乘积(OTM)值最大降幅可达27.6%。10～50 μmol·L^-1 IAA能有效提升铝胁迫下栝楼的生理活性,减缓DNA损伤程度,且安国品种的耐铝胁迫能力大于浦阳品种。

Effects of IAA on physiological response to aluminum stress and DNA damage of Trichosanthes kirilowii.

To investigate the physiological response of IAA (indoleacetic acid) to Trichosanthes kirilowii under aluminum stress and the mitigation of DNA damage, the effects of IAA (0, 10, 25, 50, 75 μmol·L^-1 denoted by I₀, I₁₀, I₂₅, I₅₀ and I₇₅, respectively) on antioxidant enzyme activity, malondialdehyde (MDA), photosynthetic characteristics, root activity, chlorophyll content and DNA damage of two varieties of T. kirilowii under 300 and 800 μmol·L^-1 aluminum environment (denoted by Al₃₀₀ and Al₈₀₀, respectively) were examined in hydroponic culture experiments with Hebei Anguo (aluminium tolerant variety) and Zhejiang Puyang Trichosanthes kirilowii (aluminum sensitive variety). The results showed that the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), photosynthesis ability, and root activity of both varieties were inhibited to different degrees by aluminum stress, MDA content was significantly increased, and DNA damage was aggravated. The maximum increase of SOD, CAT and POD activities in Anguo and Puyang T. kirilowii under aluminum stress by IAA application were 15.0%, 31.2%, 72.3% and 13.8%, 26.9%, 26.4%, respectively, chlorophyll content increased by 49.9% and 17.9%, MDA accumulation decreased by 39.2% and 22.4% and fluorescence parameters were significantly improved. The treatment of 25 μmol·L^-1 IAA significantly increased root activity by 159.1% and 90.9%, while 50 μmol·L^-1 IAA effectively slowed the DNA tailing phenomenon in roots, with the product (OTM) value of tail DNA percentage content and tail moment being decreased by 27.6%. 10-50 μmol·L^-1 IAA could effectively improve the physiological activity of T. kirilowii under aluminum stress and slow the degree of DNA damage. The tolerance of Anguo variety to aluminum stress was stronger than that of Puyang variety.