For many research projects, gathering leaf gas exchange data is essential. However, due to the length of time required to make measurements, the number of leaf samples gathered is often limited. To increase sample size, our research compared gas exchange of excised grapevine leaves to gas exchange of leaves remaining on the vine. Vines of Vitis vinifera Grenache, Cabernet Sauvignon, Chardonnay, Tempranillo, and Cabernet franc (all grafted onto 110R rootstocks) were sampled during 2013 and 2014. Research was conducted in an established vineyard near Lubbock, Texas. Using auto program mode, two LI-6400 XT machines simultaneously measured gas exchange on nearby leaves from the same shoot on the same vine. Measurements were recorded every 30 sec. After 120 sec, one leaf was excised and the auto program continued an additional eight minutes. Gas exchange means for excised and nonexcised leaves were graphed over time. In addition, gas exchange means at 60, 90, 120, 150, and 180 sec after the auto program began were exposed to ANOVA, and means were separated by Fisher’s least significance difference procedure. Data indicate gas exchange for nonexcised leaves of all varieties remained stable during the measurement period. In contrast, gas exchange for excised leaves of each variety changed during the measurement period. However, there was a period of time during which excised leaf gas exchange was not different from gas exchange measured prior to leaf excision. Therefore, it appears leaf excision might be one tool researchers could use to increase sample size when collecting vineyard leaf gas exchange data.

Funding Support: Texas AgriLife Research and Extension