Dark pericarp disease in litchi is induced by manganese stress

The Combined Use of Soil Conditioner and Foliar Sulfur Spray Successfully Prevents Dark Pericarp Disease Induced by Manganese Toxicity in Litchi

“…Phenolic compounds in fruit pericarp were extracted using the method described by Su et al (2022) [6] and determined by HPLC (Agilent 1260 Infinity II, USA) equipped with a diode array detector (Agilent G7115A, USA). The mobile phase was comprised of 2% phosphoric acid (A) and acetonitrile (B) at 0.8 mL min −1 .…”

“…All the data were the means of at least three repeats calculated by Excel 2021 and expressed as mean ± STDEV. The morbidity of DPD was computed as the weight percent of the DPFs accounting for all the fruits in one plant as the previous method [6]. All the data of plant tissues were subjected to a two-factor analysis of variance (ANOVA) and then multiple comparisons with Duncan's (p < 0.05) by SAS 9.2.…”

“…Unfortunately, dark pericarp disease (DPD), a newly identified physiological disorder induced by Mn stress in litchi, has frequently broken out at the fruit swelling stage in South China in recent years [6,7]. Litchi fruits subject to DPD are characterized by uneven dark pericarp, which markedly differs from the postharvest browning in litchi [8].…”

“…In southwest China, the annual flood and heavy rain, especially from June to August, have been increasing in recent decades [14]. Therefore, soil acidity, abnormally heavy rain, and warmer and longer summers [6,15,16] are jointly responsible for the breakout of DPD in litchi in southern China.…”

“…Liming is a useful method to decrease soil acidity and mitigate Mn stress to plants in acid soils [17,18]. Our previous work suggests that the formation of dark substances in the dark pericarp of DPD fruit might be catalyzed by peroxidase (POD) and polyphenol oxidase (PPO) [6]. Ascorbic acid is a potent inhibitor for POD and PPO in litchi fruit [19][20][21], and sulfur (S) depresses the activities of both these enzymes in plants as well [22,23].…”