PT  - JOURNAL ARTICLE
AU  - Glen L. Creasy
AU  - Porter B. Lombard
TI  - Vine Water Stress and Peduncle Girdling Effects on Pre- and Post-Veraison Grape Berry Growth and Deformability
AID  - 10.5344/ajev.1993.44.2.193
DP  - 1993 Jan 01
TA  - American Journal of Enology and Viticulture
PG  - 193--197
VI  - 44
IP  - 2
4099  - http://www.ajevonline.org/content/44/2/193.short
4100  - http://www.ajevonline.org/content/44/2/193.full
SO  - Am J Enol Vitic.1993 Jan 01; 44
AB  - To elucidate the effects of developmental xylem discontinuity in grape (Vitis vinifera L.) berries, greenhouse-grown Pinot noir vines bearing pre- or post-veraison clusters were subjected to water stress or peduncle girdling/ detaching. Berry growth rate (change in diameter per day) and deformability were measured as indicators of berry water status. Berry diameter increased slightly in pre-veraison clusters on well watered vines; diameters of berries on unwatered vines decreased significantly. Pre-veraison berry deformability was four times greater in unwatered versus watered vines on the final day of the experiment. Bagging pre-veraison clusters to slow transpiration had little effect on berry growth rate or deformability. Post-veraison berry growth rate and deformability were not affected significantly by vine water stress. Heat girdling cluster peduncles decreased pre-veraison berry growth rates by 75%, but had a negligible effect on berry deformability. Diameter loss in post-veraison berries was increased by 40% after girdling; berry deformability increased by 44%. The rate of berry diameter loss on a detached cluster was almost three times higher, and berry deformability 26% higher, than the same measurements taken from a girdled cluster. A xylem discontinuity in the berry near veraison is consistent with these findings.