Pre-harvest nitrogen and Azoxystrobin application enhances postharvest shelf-life in Butterhead lettuce
Pre-harvest nitrogen and Azoxystrobin application enhances postharvest shelf-life in Butterhead lettuce
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DOI：
10.1016/j.postharvbio.2013.04.012
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发表时间：
2013-11-01
影响因子：
7
通讯作者：
Elia, Antonio
中科院分区：
文献类型：
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作者：
Bonasia, Anna;Conversa, Giulia;Elia, Antonio
以油麦菜为试验材料，进行了两个试验（2008年3 - 5月和2009年4 - 6月）调查氮肥施用效果（0、50和100 kg ha（-1）N）和嗜球果伞素（嘧菌酯，甲基（E）-2-{2-[6-（三氟甲基）氨基]吡啶-2-基}苯甲酸酯）（2-氰基苯氧基）嘧啶-4-基氧]苯基}-3-甲氧基丙烯酸酯）对（i）收获时的产量和形态性状，（ii）物理（重量损失和干物质），目视检查（叶绿素含量和主要颜色指数），生理（相对含水量、渗透势和电解质渗漏）和营养（抗坏血酸、硝酸盐和多酚含量）原料品质及其贮藏后的变化。第一次和第二次试验的冷藏时间分别为7天和12天。在第一循环中，在早春条件下，莴苣产量低38%，并且即使产品颜色较浅[较高的L*（+6%）和较低的CHL（-21%）]，与来自第二循环的原始产品相比，其具有较低的干物质含量（-32%）、较高的电解质渗漏（EL）（+14%）和WLTrans（+8%）。在这两年中，增加施氮量和施用嘧菌酯都能提高产量（分别提高8.5%和10%）。早春（2008年）与晚春（2009年）条件相比，氮肥施肥的反应更明显（12.3%对4.8%），并且当（2008年）最高氮肥用量与嘧菌酯施用相互作用时（与其他处理相比+12.9%）。施用嘧菌酯降低了叶片中硝酸盐含量（-43%），而施氮则增加了叶片中硝酸盐含量（+53%）。在第二个实验中，当贮藏时间延长12天时，嗜球果伞素通过减少叶绿素降解（-27%）、衰老（-19%，以EL测量）和布朗宁（-53%，以h指数降低测量）来改善采后货架期。嘧菌酯还降低了原料的总多酚含量（~ 12.5%），这可能与储存期间较少的布朗宁有关。在采后贮藏期间，无论采前剂量，氮供应保持视觉质量和生理衰老指标恒定（L*，h度和EL）。绿头莴苣鲜切加工的适宜性取决于气候生长条件。收获前供应嘧菌酯提高了原料的营养质量，降低了叶片硝酸盐含量，延长了储存期。在不利的生长条件下，100 kg/ha（-1）的施氮量是合适的，而在较有利的气候条件下，50 kg/ha（-1）的施氮量更好，特别是如果土壤有机质矿化对有效氮的贡献适中，并且预计大雨不会淋溶。(c)2013爱思唯尔有限公司版权所有。
Two trials were carried out on Butterhead lettuce (March-May 2008 and April-June 2009) to investigate the effect of the application of nitrogen fertilizer (0, 50 and 100 kg ha(-1) of N) and of strobilurin (Azoxystrobin, methyl (E)-2-{2-[6-(2-cyanophenoxy)pyrimidin-4-yloxy]phenyl}-3-methoxyacrylate) on (i) yield and morphological traits at harvest, (ii) physical (weight loss and dry matter), visual (chlorophyll content and main colour indices), physiological (relative water content, osmotic potential, and electrolytic leakage), and nutritional (ascorbic acid, nitrate, and polyphenol content) quality of raw material and their changes after storage of fresh-cut leaves. Cool storage lasted 7 and 12 days in the first and second experiment, respectively. In the first cycle, under early-spring conditions, lettuce yield was lower by 38% and, even if the product was lighter coloured [higher L* (+6%) and lower CHL (-21%)], it had lower dry matter content (-32%), higher electrolyte leakage (EL) (+14%) and WLTrans (+8%) compared with the raw product from the second cycle. In both years, the increase of N supply and the application of Azoxystrobin improved yield (by 8.5% and 10%, respectively). The response in N fertilization was more evident under early-spring (2008) compared to late-spring (2009) conditions (12.3% vs. 4.8%), and when (2008) the highest N rate interacted with the application of Azoxystrobin (+12.9% compared with the other treatments). The nitrate content in leaves was always reduced by Azoxystrobin application (-43%) and increased with the N supply (+53%). In the second experiment, when storage Was prolonged for 12 days, strobilurin improved postharvest shelf-life by reducing chlorophyll degradation (-27%), senescence (-19%, measured as EL), and browning (-53%, measured as h index decrease). Azoxystrobin lowered also the total polyphenol content of raw material (-12.5%), which can be linked to less browning during storage. During postharvest storage, irrespective to the preharvest dose, N supply kept the visual quality and physiological senescence indices constant (L*, h degrees and EL). The suitability of the Butterhead lettuce to fresh-cut processing depends on climatic growing conditions. Preharvest Azoxystrobin supply improves the nutritional quality of the raw material, reducing leaf nitrate content, and the shelf-life in prolonged storage. The N rate of 100 kg ha(-1) of N is suitable under less favourable growing conditions, while the rate of 50 kg ha(-1) is better for more favourable climatic conditions, especially if a moderate contribution in available N from soil organic matter mineralization and no leaching from heavy rains is expected. (c) 2013 Elsevier B.V. All rights reserved.