FRUIT TRANSPIRATION INCREASES WITH WINDSPEED IN ACTINIDIA DELICIOSA ‘HAYWARD’

Compared with most leaves and other fruit types, the boundary-layer resistance of a kiwifruit is likely to be strongly modified by its dense covering of long (~3 mm) hairs.
We suggest that increased air movement around a fruit will reduce this entrained boundary-layer resistance by stirring up the moist air between the hairs and this will increase fruit transpiration.
This hypothesis was tested by measuring fruit transpiration at different windspeed and at different stages of fruit development.
Fruits were collected before dawn and back in the laboratory the fruit stalks were promptly recut and dipped into small vials of water.
Fruit+vial setups were then transferred to a large climate-controlled chamber (25°C, 60% RH) and exposed to windspeeds ranging from 0 to 3 ms^-1 generated by a custom-built wind machine.
Fruit transpiration rates were inferred from regular fruit weighing’s.
Results show that increases in wind speed increase fruit transpiration during the early part of the season (13 to 50 DAFS). After this, no significant effects of wind speed on fruit transpiration were detected.
It is concluded that increased air movement within the canopy early in the season resulting from windy weather and/or from appropriate orchard managements will enhance fruit transpiration and probably also fruit xylem sap influx and possibly also fruit calcium accumulation.

VII International Symposium on Kiwifruit

M. Mazzeo, B. Dichio, C. Xiloyannis, A. Lang

fruit transpiration, windspeed, boundary-layer resistance, skin resistance

https://doi.org/10.17660/ActaHortic.2011.913.51