前期低氧处理对梨虎皮病的防控及乙烯释放的影响

以‘鸭梨’为试材,空气处理为对照,分析比较前期超低氧胁迫(0.8%O2+0.5%CO2处理15 d,转入5.0%O2+0.5%CO2长期贮藏)、静态低氧气调(降温后直接转入5.0%O2+0.5%CO2)和"两阶段"缓慢降氧气调(10.0%O2+0.5%CO2处理15 d,转入5.0%O2+0.5%CO2长期贮藏)对‘鸭梨’采后贮藏过程中虎皮指数、α–法尼烯和共轭三烯、内在品质、呼吸速率、乙烯释放速率及乙烯生物合成及信号转导途径关键基因相对表达量的影响。结果表明:与空气对照相比,采用前期超低氧胁迫、静态低氧气调及"两阶段"缓慢降氧气调均显著降低了‘鸭梨’贮藏及货架期间虎皮病的发生,贮藏240 d及货架7 d后,虎皮指数由高到低依次为:空气对照(93.75%)>"两阶段"缓慢降氧气调(80.00%)>静态低氧气调(62.50%)>前期超低氧胁迫(53.57%);进一步研究发现,低氧气调抑制了果实共轭三烯的积累,较好地维持了贮藏后期果实可滴定酸和维生素C含量。同时,果实货架初期乙烯释放量显著降低,乙烯释放高峰明显推迟,Pb ACO1、Pb ACO3及Pb ACS1的相对表达量显著降低;而Pb CTR1和Pb ERF1相对表达量升高,货架后Pb ETR2基因相对表达量快速升高,乙烯大量释放。

Effects of Initial Low Oxygen Treatments on Superficial Scald Prevention and Ethylene Release in Pear

This study aimed to compare the effect of initial ultra-low oxygen stress(0.8%O2+0.5%CO2 for 15 d and then stored at 5.0%O2+0.5%CO2),static controlled atmosphere(CA)(5.0%O2+0.5%CO2)and two-stage oxygen reduction CA(10.0%O2+0.5%CO2 for 15 d,then transfer to 5.0%O2+0.5%CO2 for long period storage)on superficial scald prevention and ethylene release of‘Yali’pear.Superficial scald incidence,α-farnesene and conjugated trienols(CTols),fruit quality,respiration intensity,ethylene release rate and relative expression of ethylene biosynthesis and signaling pathway genes were compared and analyzed after storage for 180 d and 240 d plus 7 d shelf-life,and taking air treatment as control.The results showed that compared with the air,initial ultra-low oxygen stress,static CA and two-stage oxygen reduction CA could inhibit the superficial scald effectively,after storage for 240 d and 7 d shelf-life,the superficial scald incidence followed as the order of air(93.75%)>two-stage oxygen reduction CA(80.00%)>static CA(62.50%)>initial ultra-low oxygen stress(53.57%).Further research found that,CA treatments declined the accumulation of conjugated trienols in fruit peel tissue during long period storage,and better maintained the titratable acid and vitamin C contents,inhibited the ethylene production and delayed the ethylene release peaking time.At meanwhile,the relative expression of Pb ACO1,Pb ACO3 and Pb ACS1 genes were significantly decreased at the early time of shelf-life period,and the Pb CTR1 and Pb ERF1 were enhanced by initial ultra-low oxygen stress and low oxygen controlled atmosphere,while the relative expression of Pb ETR2 were up-regulated fast with the increase of ethylene production during shelf-life period.