Capillary Water in Pericarp Enhances Hypoxic Condition during On-Tree Fruit Maturation That Induces Lignification and Triggers Translucent Flesh Disorder in Mangosteen (Garcinia mangostanaL.)

Abstract

Translucent flesh of mangosteen normally occurs during fruit ripening. Rainfall, after water stress, enhanced on-tree mature green fruit to develop translucent flesh disorder more frequently. Thus, this research pursued the effect of applied water on translucent flesh disorder development. The on-tree mature green stage fruits were selected and wrapped with 3 layers of fabric sheet. After that, water was continuously dropped (flow rate of 0.6 ml/min) on the wrapped sheet for 0, 1, and 2 days before picking. The results showed that duration time of water applying enhanced the increasing of water absorption significantly in peel. All of water-treated fruits ripened within 2-3 days after harvest and obviously had high lignin in secondary cell wall. It was hypothesized that lignification played an important role in hypoxia defense mechanism since the Na2CO3-SP fractionation extracted from alcohol insoluble residue (AIR) of translucent flesh aril was higher than those of normal aril. This Na2CO3-SP reinforced the strength of cell wall complexity as well as displaying the translucency character. Hence, we concluded that the capillary water (took place in intercellular air space of fruit pericarp) induced hypoxia tolerance mechanism that triggered translucent flesh disorder in mangosteen aril.

Glycolysis Fermentative By-Products and Secondary Metabolites Involved in Plant Adaptation under Hypoxia during Pre- and Postharvest

“…A high accumulation of CO 2 is found in the intercellular space that could suppress succinate dehydrogenase activity [19,20], causing noncircular TCA flux (Figure 1). The level of reactive oxygen species (ROS) in aril increases during O 2 deficiency [18]. However, adaptability of mangosteen fruit under hypoxia is detected by inducing lignification in the aril flesh, which is related to the phenylpropanoid pathway, including phenylalanine amonialyase (PAL), cinnamyl alcohol dehydrogenase (CAD), and peroxidase (POD) activities.…”

“…On the other hand, translucent aril contains a mild increase of WSP, but the Na 2 CO 3 -SP significantly increases in parallel of high lignin accumulation in the aril cell wall, especially in the segment containing a complete seed. Thus, the aril firmness of translucent flesh is higher than healthy aril, exhibiting stiffness flesh[18].…”