Ethylene-induced tolerance to non-chilling peel pitting as related to phenolic metabolism and lignin content in 'Navelate' fruit
Ethylene-induced tolerance to non-chilling peel pitting as related to phenolic metabolism and lignin content in 'Navelate' fruit
复制标题
DOI：
10.1016/j.postharvbio.2007.01.019
复制
发表时间：
2007-08-01
影响因子：
7
通讯作者：
Lafuente, Maria T.
中科院分区：
文献类型：
--
作者：
Cajuste, Jacques F.;Lafuente, Maria T.
研究了苯丙素类代谢参与乙烯处理对降低“脐型”橙子果实采后非冷面点蚀的有益作用。我们检测了在22 ℃和恒定高RH（90-95%）的空气中贮藏的水果（对照水果）和在22 ℃和90- 95%RH下用2或10 μ L L-1乙烯处理4天，然后转移到相同温度和RH的空气中的水果的外果皮和内果皮组织中的酶苯丙氨酸解氨酶（PAL; EC 1.11.1.7）、可溶性和离子结合的过氧化物酶（POD，EC 4.3.1.5）的活性以及酚和木质素含量的变化。非冷却果皮点蚀是可见的，在控制水果后7天，急剧增加，长达14天，保持几乎恒定的，此后，而空调的水果与乙烯浓度大大降低了它。可溶性和细胞壁相关的POD活性下降，PAL短暂增加，在对照水果的果皮和果皮的外观损害。酚类和木质素含量略有增加，在果皮，而在棕榈叶，这有一个较低的PAL活性比果皮，酚类含量几乎没有变化，木质素下降。因此，PAL在两种组织中的激活和木质素和酚类在外果皮中的轻微上升可能反映了对苯丙素类产品的需求，以减少非冷却果皮点蚀。此外，POD在这两个组织中的下降，也缺乏的能力，提高酚类和木质素含量的葡萄酒可能与空气处理的'Navelate'水果克服这种生理障碍的能力低。果实条件与10 μ L L-1乙烯保持较高的酚和木质素水平高达14天，更高的可溶性和离子结合的POD水平高达21天，而施加2 μ L L-1乙烯效果较差。两种乙烯浓度都激活了果皮转移到空气中后的可溶性POD和PAL，但程度低于果皮。这种增加对酚含量的影响很小。同样，乙烯处理延迟木质素的下降，但控制和乙烯处理的水果之间最重要的差异发生时，果皮损伤是非常明显的控制水果。因此，总体结果表明，酚类代谢可能需要建立保护屏障，这将有助于“脐”果，以减少非冷却果皮点蚀，虽然额外的防御机制，这将有助于减少非冷却果皮点蚀在“脐”果出现乙烯预处理诱导。(c)2007 Elsevier B. V.保留所有权利。
The involvement of phenylpropanoid metabolism in the beneficial effect of ethylene conditioning in reducing postharvest non-chilling peel pitting occurring in 'Navelate' orange fruit has been investigated. We examined changes in the activities of the enzymes phenylalanine ammonia-lyase (PAL; EC 4.3.1.5), soluble and ionically bound peroxidase (POD, EC 1.11.1.7) and on phenolic and lignin contents in the flavedo and albedo tissues of fruit stored in air at 22 degrees C and constant high (90-95%) RH (control fruit), and in fruit conditioned for 4 days with 2 or 10 mu L L-1 ethylene at 22 C and 90-95% RH, and then transferred to air at the same temperature and RH. Non-chilling peel pitting was visible in control fruit after 7 days and sharply increased for up to 14 days, to remain nearly constant thereafter; while conditioning the fruit with both ethylene concentrations considerably reduced it. Soluble and cell wall-related POD activities decreased, and PAL transiently increased, in the albedo and flavedo of control fruit with the appearance of damage. Phenolic and lignin contents slightly increased in the flavedo, while in the albedo, which had a lower PAL activity than the flavedo, phenolic contents barely changed and lignin decreased. Thus, the activation of PAL in both tissues and the slight rise in lignin and phenols in the flavedo may reflect a demand for phenylpropanoid products to reduce non-chilling peel pitting. Furthermore, the decline in POD in both tissues and also the lack of the ability of the albedo to increase phenolic and lignin contents might be related to the low ability of air-treated 'Navelate' fruit to overcome this physiological disorder. Fruit conditioned with 10 mu L L-1 ethylene maintained higher phenol and lignin levels up to 14 days and higher soluble and ionically bound POD levels up to 21 days in the flavedo, while applying 2 mu L L-1 ethylene was less effective. In the albedo, both ethylene concentrations activated soluble POD after transfer of fruit to air and PAL also, though to a lower extent than in the flavedo. Such an increase had a low impact on the phenolic content. Likewise, both ethylene treatments delayed the decline in lignin in the albedo, but the most important differences between control and ethylene-treated fruit occurred when peel damage was very evident in control fruit. The overall results indicate, therefore, that phenolic metabolism may be required for building protecting barriers that would help 'Navelate' fruit to reduce non-chilling peel pitting, although additional defense mechanisms which would assist in reducing non-chilling peel pitting in 'Navelate' fruit appear to be induced by ethylene pretreatment. (c) 2007 Elsevier B.V. All rights reserved.