TY - JOUR

T1 - Lenticels and apple fruit transpiration

AU - Khanal, Bishnu P.

AU - Si, Yiru

AU - Knoche, Moritz

N1 - Funding information: This work was funded in part by grants from the Deutsche Forschungsgemeinschaft ( KN 402 ). We thank Dr. Erik Schulte and Mr. Stefan Eschke, Federal Plant Variety Office for samples of the apple fruit, Dr. Sandy Lang for his thoughtful comments on this manuscript.

PY - 2020/9

Y1 - 2020/9

N2 - Lenticels are sites of preferential gas exchange and water loss. Here we quantified the water vapor permeance of lenticels and their contribution to total transpiration in different regions of the apple (Malus × domestica Borkh.) fruit skin. Along the transect pedicel to calyx, lenticel area decreased (smaller lenticels), while lenticel density per unit area and cumulative lenticel area both increased. Lenticel density was highest in ‘Renoirciv’ (13.6 ± 0.5 cm−2 in the cheek region) followed by ‘Wellant’ (6.9 ± 0.5 cm−2 in the cheek region) apple. About 10 % of lenticels had microcracks as indexed by infiltration by a solution containing a silicone surfactant. There was no infiltration in the absence of the surfactant. In ‘Wellant’ the relative contribution of lenticellular water loss to the total was lower in the pedicel region (14 %) than in the calyx region (25 %). The contribution of lenticels differed among cultivars averaging in the cheek region 19 % in ‘Wellant’ and 8 % in ‘Pinova’ apple. The permeance of the periderm of a lenticel exceeded that of a russeted fruit skin 5.8-fold in ‘Wellant’ and 5.2-fold in ‘Pinova’. Skin permeance was positively and significantly related to both lenticel density and cumulative lenticel area within a region or between regions in ‘Wellant’. Across nine apple cultivars, permeance was significantly and positively related to lenticel density ( r2 = 0.52*) and to cumulative lenticel area ( r2 = 0.84***). The mechanistic basis for the increased water vapor permeability of lenticels is discussed.

AB - Lenticels are sites of preferential gas exchange and water loss. Here we quantified the water vapor permeance of lenticels and their contribution to total transpiration in different regions of the apple (Malus × domestica Borkh.) fruit skin. Along the transect pedicel to calyx, lenticel area decreased (smaller lenticels), while lenticel density per unit area and cumulative lenticel area both increased. Lenticel density was highest in ‘Renoirciv’ (13.6 ± 0.5 cm−2 in the cheek region) followed by ‘Wellant’ (6.9 ± 0.5 cm−2 in the cheek region) apple. About 10 % of lenticels had microcracks as indexed by infiltration by a solution containing a silicone surfactant. There was no infiltration in the absence of the surfactant. In ‘Wellant’ the relative contribution of lenticellular water loss to the total was lower in the pedicel region (14 %) than in the calyx region (25 %). The contribution of lenticels differed among cultivars averaging in the cheek region 19 % in ‘Wellant’ and 8 % in ‘Pinova’ apple. The permeance of the periderm of a lenticel exceeded that of a russeted fruit skin 5.8-fold in ‘Wellant’ and 5.2-fold in ‘Pinova’. Skin permeance was positively and significantly related to both lenticel density and cumulative lenticel area within a region or between regions in ‘Wellant’. Across nine apple cultivars, permeance was significantly and positively related to lenticel density ( r2 = 0.52*) and to cumulative lenticel area ( r2 = 0.84***). The mechanistic basis for the increased water vapor permeability of lenticels is discussed.

KW - Lenticel

KW - Malus

KW - Periderm

KW - Permeance

KW - Water vapor

UR - http://www.scopus.com/inward/record.url?scp=85085279955&partnerID=8YFLogxK

U2 - 10.1016/j.postharvbio.2020.111221

DO - 10.1016/j.postharvbio.2020.111221

M3 - Article

AN - SCOPUS:85085279955

VL - 167

JO - Postharvest Biology and Technology

JF - Postharvest Biology and Technology

SN - 0925-5214

M1 - 111221

ER -