模拟低温对龙眼果实发育及其果皮H2O2代谢的影响

摘要

以3年生‘储良’龙眼盆栽树为试验材料,于花后28 d时采取模拟低温(昼夜15/10℃)处理,研究该处理对龙眼果实发育及其果皮过氧化氢(H2O2)含量、过氧化物酶(POD)活性与过氧化氢酶(CAT)活性的影响,以常温(昼夜28/23℃)处理为对照.结果表明:模拟低温处理后的龙眼成熟果实单果重明显偏小、发育期显著增加,主要是延长了果实发育前期,但其累积落果率与对照差异不显著.模拟低温期间,果实生长缓慢,落果较少,果皮POD、CAT活性与H2O2含量均低于对照;但从处理后43 d起开始解除模拟低温后,果实发育迅速,落果剧烈,果皮POD、CAT活性及H2O2含量均呈先升后降的变化趋势,且在果实发育中后期均明显高于对照.这表明,模拟低温抑制了果实生长、延长了果实发育期,温度骤然回升引起果皮H2O2的爆发及果皮抗氧化酶活性的提高,进而诱导了果实大量脱落.%This study was to investigate the effects of simulated low temperature (15/10 ℃,day/night),treated at 28 days after anthesis in the phytotron,on the fruit development and the pericarp hydrogen peroxide (H2O2) content and its peroxidase (POD) and catalase (CAT) activities in the three-year-old potted trees of longan (Dimocarpus longan Lour.cv.Chuliang),and the treatment of warm temperature (28/23 ℃,day/night) was used as the control.The results showed that a smaller fruit at harvest and a longer period of fruit development chiefly due to a longer early fruit development were significantly occurred in the potted longan trees after treatment of simulated low temperature,while there was no significant difference in the cumulative fruit drop rate compared to those exposed to the control temperature regime.Accompanied by the slower fruit growth and the fewer fruit drop during simulated low temperature,the H2O2 content and POD,CAT activities of periearp were also lower than those of the control.However,the rapid fruit development and the severe fruit abscission were obviously occurred after removing low temperature from 43 d after treatment,along with the distinctly changes of increasing firstly and decreasing later in the content of H2O2 and the activities of POD and CAT in pericarp which were clearly higher than those of the control in the mid-late stage of fruit growth,suggested that simulated low temperature repressed fruit growth and extended the period of fruit development,and an abrupt raised temperature caused the outburst of H2O2 and the increase of antioxidant enzymes activities in pericarp and thus induced the severe fruit abscission.