Intumescence: A Serious Physiological Disorder in Plants

Abstract

Intumescence injury is a physiological disorder that occurs in various plants. Initially, this injury was observed in the field, and it has become a problem in greenhouse and plant factory cultivations in recent years. Many terms refer to this disorder, with intumescence and oedema as the main two that are still frequently used. Intumescence is characterized as hypertrophied and/or hyperplasia of epidermal cells, while oedema refers to a lesion caused by excess water accumulated in the plant tissues. Morphological characteristics of intumescence differ among plants. Environmental factors, such as light and humidity, mainly caused this problem, and recent reports associate intumescence with a calcium-related injury. In tomato plants, low ultraviolet combined with high humidity affected the cuticle layer, and the high humidity lowered the transpiration rate, decreasing the calcium uptake to the leaves. This combination leads to cell hypertrophy and intumescence injury. The severity of this disorder is different among cultivars within one species, and this phenomenon is highly genetically dependent. Some approaches are proposed to limit intumescence injury, which applies to the field or controlled environments. This review summarized the information regarding intumescence injury, as well as the future approaches regarding this study.