Carbohydrate Injections as a Potential Option
to Improve Growth and Vitality of Live Oaks
Tomás Martínez-Trinidad, W. Todd Watson, Michael A. Arnold,
Leonardo Lombardini, and David N. Appel
Abstract: This study evaluates the effects of carbohydrate injections on the growth and vitality of live oak (Quercus virginiana P. Miller). Glucose, sucrose, or a 50:50 mixture of both carbohydrates at increasing concentrations [0, 40, 80, and 120 g/L (0, 5.3, 10.6, and 16.0 oz/gal)] were injected into live oaks. Trunk and root growth, net photosynthesis, root and twig carbohydrate concentration, and chlorophyll fluorescence were monitored. Isotope composition of twig and root samples was measured as an indicator of injected carbohydrate distribution. There were significant differences (P < 0.05) in trunk growth among types of carbohydrates, but no significant differences for carbohydrate concentrations. The mixtures of sucrose and glucose had the largest effect on growth compared to either sugar alone, suggesting that glucose and sucrose alone were used in processes other than trunk growth. 50:50 mixtures caused a greater effect on overall mean growth indices than either sugar alone. Glucose content in twigs and starch in roots were significantly different (P < 0.05) among overall means for concentrations with increased levels found in trees treated with the greatest concentrations. Chlorophyll fluorescence Fv/Fm revealed highly significant differences (P < 0.001) among overall concentrations. Carbon isotope values did not reveal a definite trend that corroborated the exogenous carbohydrate distribution. Results from this experiment suggest that carbohydrate trunk injections can have an impact on growth and vitality of live oak.
Keywords: Glucose; Quercus virginiana; Sucrose; Sugars; Tree Vitality