Occurrence of Pinitol in Foliage of Several Forage Legume Species1

Abstract

Although it has been reported that (D) pinitol (1D‐3‐0‐ methyl‐chiro‐inositol) occurs naturally in leguminous species, there is a lack of information concerning its concentration in foliage of forage legumes. The purpose of this research was to determine the pinitol concentration in the foliage of several forage legume species and the relative concentration of pinitol in leaf, stem and root tissue. Pinitol concentration was determined in foliage of five cultivate of alfalfa (Medicago sativa L.), 11 cultivars of red clover (Trifolium pratense L.), 13 cultivars of white clover (Trifolium repens L.), and 9 cultivars of birdsfoot trefoil (Lotus corniculatus L.) grown in small field plots. Pinitol distribution in leaf, stem, and petiole tissue was determined for three cultivars of arrowleaf clover (Trifolium vesiculosum Savi.) and Ladino white clover grown in the greenhouse There were minor but significant differences in pinitol concentration among cultivars within each species Pinitol concentration was nearly equal to sucrose concentration in red clover and birdsfoot trefoil foliage and nearly half as high in alfalfa and white clover cultivars The range of pinitol concentrations among species was only 6.7 mg/g of dry tissue, being lowest for red clover (20.4 mg/g) and highest for white clover foliage (27.1 mg/g). In general, concentrations of pinitol and sucrose were similar in leaf and stem tissue of greenhouse grown plants. Pinitol concentration was 4 to 8 times higher in the foliage than in root tissue. The data indicate a relatively high concentration of pinitol in the foliage from forage legumes and imply the need for research on pinitol metabolism, physiological function, and influence on forage quality.