对羟基苯甲酸胁迫对不同草莓品种光合作用及叶绿素荧光特性的影响

以对连作障碍具有不同抗性的草莓品种‘土特拉’、‘丰香’和‘全明星’为试材，采用温室盆栽试验研究了50、100和200 mg ? kg-1对羟基苯甲酸胁迫对草莓光合色素含量、光合作用气体交换参数和叶绿素荧光动力学特征的影响。结果表明：对羟基苯甲酸胁迫降低了3个品种草莓叶片叶绿素a、叶绿素b和类胡萝卜素的含量，且‘全明星’降幅最大。除‘丰香’的净光合速率和蒸腾速率在低浓度对羟基苯甲酸胁迫下有所提高外，‘土特拉’和‘全明星’的净光合速率、气孔导度和蒸腾速率均因对羟基苯甲酸胁迫而降低，且浓度越高降幅越大。100和200 mg ? kg-1对羟基苯甲酸胁迫均显著提高了草莓初始荧光Fo和非光化学猝灭系数qN；最高浓度胁迫下，‘全明星’、‘丰香’和‘土特拉’Fo分别比对照提高了15.1%、21.5%和9.3%，qN分别提高了131.3%、190.5%和26.6%。3个品种草莓最大荧光、PSⅡ反应中心潜在活性、PSⅡ最大光化学效率、PSⅡ有效光能转化效率和PSⅡ光合电子传递量子效率均随对羟基苯甲酸胁迫浓度的升高呈先升后降的趋势；各草莓品种叶绿素荧光参数综合优势表现为‘土特拉’>‘丰香’>‘全明星’。除50 mg ? kg-1胁迫没有明显影响‘丰香’和‘土特拉’干物质积累外，其他处理均显著降低了各品种地上部和地下部干质量及根冠比。‘土特拉’光合色素、光合作用和叶绿素荧光特性受对羟基苯甲酸影响小于‘全明星’和‘丰香’，维持较强的光合性能可能是对连作障碍具有较强抗性的生理基础。

Impacts of 4-Hydroxybenzoic Acid on Characteristics of Photosynthesis and Chlorophyll Fluorescence of Different Strawberry Cultivars

A pot experiment was conducted to determine the impacts of the low，middle and high concentrations of 4-hydroxybenzoic acid on the chlorophyll content，photosynthesis gas exchange parameters and chlorophyll fluorescence parameters of the different strawberry（Fragaria × ananassa Duch.） cultivars（‘Tutela’，‘Toyonoka’and‘All Star’）. The results showed that the content of chlorophyll a，chlorophyll b and carotenoids of three strawberry cultivars were reduced under the 4-hydroxybenzoic acid stress with the largest decline of‘All Star’. The net photosynthetic rate and transpiration rate of‘Toyonoka’with a little increase under the lowest concentration of 4-hydroxybenzoic acid，while the net photosynthetic rate，stomatal conductance and transpiration rate of‘Toyonoka’，‘Tutela’and‘All Star’Were all decreased under the 4-hydroxybenzoic acid stress，and the greater decline the higher concentration. The initial fluorescence（F_o）and non-photochemical quenching coefficient（q_N）were significantly increased under 100 mg · kg^-1 and 200 mg · kg^-1 4-hydroxybenzoic acid stress. Under the highest concentration of 4-hydroxybenzoic acid stress，the initial fluorescences（F_o）of‘All Star’，‘Toyonoka’and‘Tutela’were increased by 15.1%，21.5% and 9.3%，respectively，and non-photochemical quenching coefficient of the three strawberry cultivars were increased by 131.3%，190.5% and 26.6%，respectively. The maximum fluorescence（F_m），maximal photochemical efficiency（F_v/F_m），efficiency of excitation capture of open PSⅡ center（F_v′/F_m′）and effective quantum efficiency of PSⅡ（Φ_PSII）of three strawberry cultivars were firstly increased with the increasing concentration of 4-hydroxybenzoic acid and then decreased. The comprehensive advantage of chlorophyll fluorescence parameters of three strawberry cultivars was‘Tutela’>‘Toyonoka’>‘All Star’. Low 4-hydroxybenzoic acid concentration（50 mg · kg^-1） didn’t affect significantly the dry matter accumulation of‘Tutela’and‘Toyonoka’，but the aboveground and underground dry quality，and ratio of root/shoot per plant of three strawberry cultivars were significantly decreased in other treatments. The photosynthetic pigments，photosynthesis and chlorophyll fluorescence characteristics of‘Tutela’were less influenced by 4-hydroxybenzoic acid stress than‘All Star’and‘Toyonoka’. So a higher photosynthetic performance might be an important physiological trait of resistant cultivars in the adaptability to replant disease.