Athoo Thomas O, Winkler Andreas, Knoche Moritz
Institute of Horticultural Production Systems, Leibniz University Hannover, Herrenhäuser Straße 2, 30419 Hannover, Germany.
Plants (Basel). 2020 Jul 16;9(7):898. doi: 10.3390/plants9070898.
Russeting is an important surface disorder of many fruitcrop species. The mango cultivar 'Apple' is especially susceptible to russeting. Russeting compromises both fruit appearance and postharvest performance. The objective was to identify factors, mechanisms, and consequences of russeting in 'Apple' mango. Russeting was quantified on excised peels using image analysis and a categorical rating scheme. Water vapour loss was determined gravimetrically. The percentage of the skin area exhibiting russet increased during development. Russet began at lenticels then spread across the surface, ultimately forming a network of rough, brown patches over the skin. Cross-sections revealed stacks of phellem cells, typical of a periderm. Russet was more severe on the dorsal surface of the fruit than on the ventral and more for fruit in the upper part of the canopy than in the lower. Russet differed markedly across orchards sites of different climates. Russet was positively correlated with altitude, the number of rainy days, and the number of cold nights but negatively correlated with minimum, maximum, and mean daily temperatures, dew point temperature, and heat sum. Russeted fruit had higher transpiration rates than non-russeted fruits and higher skin permeance to water vapour. Russet in 'Apple' mango is due to periderm formation that is initiated at lenticels. Growing conditions conducive for surface wetness exacerbate russeting.
果皮锈斑是许多水果作物品种的一种重要表面病害。芒果品种“苹果芒”尤其容易出现果皮锈斑。果皮锈斑会影响果实外观和采后表现。目的是确定“苹果芒”果皮锈斑的影响因素、形成机制及后果。利用图像分析和分类评级方案对切除的果皮上的锈斑进行量化。通过重量法测定水分损失。在果实发育过程中，出现锈斑的果皮面积百分比增加。锈斑从皮孔开始，然后蔓延至整个表面，最终在果皮上形成粗糙的褐色斑块网络。横截面显示有木栓细胞堆叠，这是周皮的典型特征。果实背面上的锈斑比腹面更严重，树冠上部的果实比下部的更严重。不同气候条件的果园中，锈斑情况差异显著。锈斑与海拔、降雨天数和寒冷夜晚的数量呈正相关，但与日最低温度、最高温度和平均温度、露点温度及积温呈负相关。有锈斑的果实比没有锈斑的果实具有更高的蒸腾速率，并且果皮对水蒸气的渗透性更高。“苹果芒”的果皮锈斑是由于在皮孔处开始形成周皮所致。有利于表面湿润的生长条件会加剧果皮锈斑的形成。
