TY - JOUR

T1 - Progressive decline in xylem inflow into developing plums

AU - Khanal, Bishnu P.

AU - Acharya, Indu

AU - Knoche, Moritz

N1 - Funding Information: This research was funded by grant KN 402/20-1 from the Deutsche Forschungsgemeinschaft. The publication of this article was funded by the Open Access Fund of Leibniz Universit€at Hannover. We thank Dr. Alexander Lang and Dr. Andreas Winkler for helpful comments on an earlier version of this manuscript.

PY - 2021/10

Y1 - 2021/10

N2 - Recent evidence suggests xylem functionality may decline in developing European plums. Loss of xylem function may have negative consequences for fruit quality. The aim of this study was to establish and localize the loss of xylem functionality, both spatially and temporally using detached fruit. Fruit were detached from the tree under water and fed through a capillary mounted on the cut end of the pedicel. The rate of water movement through the capillary was recorded. Fruit were held above dry silica gel [≈0% relative humidity (RH)] or above water (≈100% RH) to maximize or minimize transpiration, respectively. Water inflow rate depended on developmental stage. It increased from stage I to a maximum at early stage III and then decreased until maturity. Feeding acid fuchsin to developing fruit revealed a progressive decline in dye distribution. The decline progressed basipetally, from the stylar end toward the stem end. At the mature stage III, only the pedicel/fruit junction was stained. The same pattern was observed in four further plum cultivars at the mature stage III. The inflow into early stage III fruit decreased as the RH increased. In contrast, the inflow was less dependent of RH at the mature stage III. Abrading the fruit skin cuticle had no effect on water inflow during early and mature stage III but did markedly increase fruit transpiration rate. Decreasing the osmotic potential (more concentrated) of the feeding solution decreased the water inflow. Our results indicate a progressive loss of xylem functionality in European plum. Transpiration and osmotic pull are the main drivers of this xylem inflow.

AB - Recent evidence suggests xylem functionality may decline in developing European plums. Loss of xylem function may have negative consequences for fruit quality. The aim of this study was to establish and localize the loss of xylem functionality, both spatially and temporally using detached fruit. Fruit were detached from the tree under water and fed through a capillary mounted on the cut end of the pedicel. The rate of water movement through the capillary was recorded. Fruit were held above dry silica gel [≈0% relative humidity (RH)] or above water (≈100% RH) to maximize or minimize transpiration, respectively. Water inflow rate depended on developmental stage. It increased from stage I to a maximum at early stage III and then decreased until maturity. Feeding acid fuchsin to developing fruit revealed a progressive decline in dye distribution. The decline progressed basipetally, from the stylar end toward the stem end. At the mature stage III, only the pedicel/fruit junction was stained. The same pattern was observed in four further plum cultivars at the mature stage III. The inflow into early stage III fruit decreased as the RH increased. In contrast, the inflow was less dependent of RH at the mature stage III. Abrading the fruit skin cuticle had no effect on water inflow during early and mature stage III but did markedly increase fruit transpiration rate. Decreasing the osmotic potential (more concentrated) of the feeding solution decreased the water inflow. Our results indicate a progressive loss of xylem functionality in European plum. Transpiration and osmotic pull are the main drivers of this xylem inflow.

KW - European plum

KW - Osmotic pull

KW - Prunus ×domestica

KW - Transpiration

KW - Water inflow

KW - Xylem

UR - http://www.scopus.com/inward/record.url?scp=85116714069&partnerID=8YFLogxK

U2 - 10.21273/HORTSCI16012-21

DO - 10.21273/HORTSCI16012-21

M3 - Article

AN - SCOPUS:85116714069

VL - 56

SP - 1263

EP - 1268

JO - HORTSCIENCE

JF - HORTSCIENCE

SN - 0018-5345

IS - 10

ER -