TY - JOUR

T1 - Russeting in Apple Is Initiated After Exposure to Moisture Ends

T2 - I. Histological Evidence

AU - Chen, Yun Hao

AU - Straube, Jannis

AU - Khanal, Bishnu P.

AU - Knoche, Moritz

AU - Debener, Thomas

N1 - Funding Information: Funding: This research was funded by a grant (KN 402) from the Deutsche Forschungsgemeinschaft (DFG). The publication of this article was funded by the Open Access fund of the Leibniz Universität Hannover.

PY - 2020/10

Y1 - 2020/10

N2 - Russeting (periderm formation) is a critical fruit-surface disorder in apple (Malus × domestica Borkh.). The first symptom of insipient russeting is cuticular microcracking. Humid and rainy weather increases russeting. The aim was to determine the ontogeny of moisture-induced russeting in ‘Pinova’ apple. We recorded the effects of duration of exposure to water and the stage of fruit development at exposure on microcracking, periderm formation and cuticle deposition. Early on (21 or 31 days after full bloom; DAFB) short periods (2 to 12 d) of moisture exposure induced cuticular microcracking—but not later on (66 or 93 DAFB). A periderm was not formed during moisture exposure but 4 d after exposure ended. A periderm was formed in the hypodermis beneath a microcrack. Russeting frequency and severity were low for up to 4 d of moisture exposure but increased after 6 d. Cuticle thickness was not affected by moisture for up to 8 d but decreased for longer exposures. Cuticular ridge thickness decreased around a microcrack. In general, moisture did not affect cuticular strain release. We conclude that a hypodermal periderm forms after termination of moisture exposure and after microcrack formation. Reduced cuticle deposition may cause moisture-induced microcracking and, thus, russeting.

AB - Russeting (periderm formation) is a critical fruit-surface disorder in apple (Malus × domestica Borkh.). The first symptom of insipient russeting is cuticular microcracking. Humid and rainy weather increases russeting. The aim was to determine the ontogeny of moisture-induced russeting in ‘Pinova’ apple. We recorded the effects of duration of exposure to water and the stage of fruit development at exposure on microcracking, periderm formation and cuticle deposition. Early on (21 or 31 days after full bloom; DAFB) short periods (2 to 12 d) of moisture exposure induced cuticular microcracking—but not later on (66 or 93 DAFB). A periderm was not formed during moisture exposure but 4 d after exposure ended. A periderm was formed in the hypodermis beneath a microcrack. Russeting frequency and severity were low for up to 4 d of moisture exposure but increased after 6 d. Cuticle thickness was not affected by moisture for up to 8 d but decreased for longer exposures. Cuticular ridge thickness decreased around a microcrack. In general, moisture did not affect cuticular strain release. We conclude that a hypodermal periderm forms after termination of moisture exposure and after microcrack formation. Reduced cuticle deposition may cause moisture-induced microcracking and, thus, russeting.

KW - Cuticle

KW - Malus × domestica

KW - Periderm

KW - Russeting

KW - Strain

KW - Surface moisture

UR - http://www.scopus.com/inward/record.url?scp=85091935844&partnerID=8YFLogxK

U2 - 10.3390/plants9101293

DO - 10.3390/plants9101293

M3 - Article

AN - SCOPUS:85091935844

VL - 9

SP - 1

EP - 18

JO - Plants

JF - Plants

IS - 10

M1 - 1293

ER -