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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F_o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’F_o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。
Strawberry varieties ’Tetra,’ ’Fengxiang’ and ’All-Star’ with different resistance to continuous cropping obstacle were used as materials to study the effects of 50, 100 and 200 mg · kg ~ (-1) Effects of Hydroxybenzoic Acid Stress on Photosynthetic Pigment Content, Photosynthetic Gas Exchange Parameters and Chlorophyll Fluorescence Kinetics in Strawberry. The results showed that the stress of p-hydroxybenzoic acid decreased the contents of chlorophyll a, chlorophyll b and carotenoid in three varieties of strawberry leaves, and the decline of ’All-Star’ was the largest. The net photosynthetic rate, stomatal conductance and transpiration rate of ’otter’ and ’all-star’ were all significantly different from those of ¡° All-Star¡ ± except that the net photosynthetic rate and transpiration rate of ¡¯Xiangxiang¡¯ were increased under the low concentration of p-hydroxybenzoic acid Hydroxybenzoic acid decreased stress, and the higher the decline the greater the concentration. Under the stress of 100 and 200 mg · kg -1, the initial fluorescence F_o and the non-photochemical quenching coefficient qN of strawberry were significantly increased, while those of ’Allstar’, ’Fengxiang’ and ’Tout F’o increased by 15.1%, 21.5% and 9.3%, respectively, and qN increased by 131.3%, 190.5% and 26.6% respectively. The maximum fluorescence of strawberry, the potential activity of PSⅡ reaction center, the maximum photochemical efficiency of PSⅡ, the effective light energy conversion efficiency of PSⅡ and the quantum efficiency of photosynaptic electron transport of PSⅡ firstly increased and then decreased with the increase of the concentration of p-hydroxybenzoic acid. The comprehensive advantage of the varieties chlorophyll fluorescence parameters showed that: ’Ìttra>’ abundance ’>’ All-Star ’. Except for 50 mg · kg -1 stress, dry matter accumulation and root dry weight ratio of ’Shangxiang’ and ’Datura’ were significantly decreased in other treatments. Photosynthetic pigments, photosynthesis and chlorophyll fluorescence characteristics of ’Toutra’ were less affected by para-hydroxybenzoic acid than that of ’All-Star’ and ’Fragrant Fragrans’. Maintaining strong photosynthetic capacity may be the physiological basis of strong resistance to continuous cropping obstacle .