Qu Ying, Jiang Lu, Wuyun Tana, Mu Shouyuan, Xie Fuchun, Chen Yajun, Zhang Lu
College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin, China.
Chair of Crop Science and Plant Biology, Estonian University of Life Sciences, Tartu, Estonia.
Front Plant Sci. 2020 Sep 10;11:566824. doi: 10.3389/fpls.2020.566824. eCollection 2020.
Senescence is the main limitation for cut foliage display in vase. Naturally occurring polyamines such as putrescine (Put) have been considered effective anti-senescence agents. However, effect of Put on cut foliage in vase in a realistic indoor environment has not yet been revealed. In the present study, effects of Put spraying on the postharvest performance of cut foliage of L. were investigated. Cut fronds sprayed with deionized water (Put0) showed visible injuries after 10 days in vase. Meanwhile, chlorophyll (Chl), soluble protein (Sp), and proline (Pro) content were decreased by 60.15, 57.93, and 73.09% respectively, photochemical activity reflected by Chl fluorescence parameters was inhibited, whereas electrolyte leakage (EL), contents of soluble sugar (Ss), malondialdehyde (MDA), and hydrogen peroxide (HO) were increased (+194.29, +44.83, +34.06, and +178.01%, respectively). Put spraying extended the vase life of the cut foliage and the 2.0 mM Put had a longer vase life (21 days) than 0.2 mM (15 days). Leaf spraying of 2.0 mM Put for 10 days significantly ameliorated the losses of Chl, Sp, and Pro content (-10.72, -26.29, and -42.64%, respectively), followed by 0.2 mM Put (-27.36, -36.24, and -60.55%, respectively). Put spraying also improved photochemical capability and prevented membrane impairment as well as visible injury in comparison with Put0. In addition, 2.0 mM Put had a better mitigating ability than that of 0.2 mM. Leaf spraying of 2.0 mM Put greatly reduced the decline of the effective quantum yield of photochemical energy conversion in PSII (ΦPSII), the maximal quantum yield of PSII photochemistry measured in the dark-adapted state (Fv/Fm) and electron transport rate (ETR) (-7.89, -12.91, and -10.06%, respectively), and also inhibited the increases of EL, MDA, Ss, and HO (+31.87, +6.43, +16.22, and +49.40%, respectively). Overall, Put played important roles in deterring the degradation of Chl, Ss, and Pro, detoxifying the HO, weakening the sugar signaling, mitigating the decline of photochemical activity, and eventually postponing the leaf senescence. The present study gives new insights into effects of Put on leaf senescence and provides a strategy for preserving post-harvest cut foliage.
衰老现象是瓶插切叶观赏期的主要限制因素。天然存在的多胺，如腐胺（Put），被认为是有效的抗衰老剂。然而，在实际室内环境中，腐胺对瓶插切叶的影响尚未明确。在本研究中，我们调查了喷施腐胺对L.切叶采后性能的影响。用去离子水喷施的切叶（Put0）在瓶插10天后出现明显损伤。同时，叶绿素（Chl）、可溶性蛋白（Sp）和脯氨酸（Pro）含量分别下降了60.15%、57.93%和73.09%，叶绿素荧光参数反映的光化学活性受到抑制，而电解质渗漏（EL）、可溶性糖（Ss）、丙二醛（MDA）和过氧化氢（HO）含量增加（分别增加了194.29%、44.83%、34.06%和178.01%）。喷施腐胺延长了切叶的瓶插寿命，2.0 mM腐胺处理的瓶插寿命（21天）比0.2 mM腐胺处理的（15天）更长。喷施2.0 mM腐胺10天可显著改善Chl、Sp和Pro含量的损失（分别下降10.72%、26.29%和42.64%），其次是0.2 mM腐胺处理（分别下降27.36%、36.24%和60.55%）。与喷施去离子水相比，喷施腐胺还提高了光化学能力，防止了膜损伤和可见损伤。此外，2.0 mM腐胺的缓解能力优于0.2 mM腐胺。喷施2.0 mM腐胺可大大降低PSII中光化学能量转换有效量子产率（ΦPSII）、暗适应状态下PSII光化学最大量子产率（Fv/Fm）和电子传递速率（ETR）的下降幅度（分别下降7.89%、12.91%和10.06%），同时也抑制了EL、MDA、Ss和HO的增加（分别增加31.87%、6.43%、16.22%和49.40%）。总体而言，腐胺在抑制Chl、Ss和Pro的降解、清除HO、减弱糖信号传导、缓解光化学活性下降以及最终延缓叶片衰老方面发挥了重要作用。本研究为腐胺对叶片衰老的影响提供了新的见解，并为采后切叶保鲜提供了一种策略。
