Variation in Caloric Values of Annual and Perennial Lupines (Lupinus: Leguminosae)

Caloric analyses of plant parts from three species of Lupinus reveal significant differences among plant parts, among species and over time which are ecologically interpretable. Higher caloric values (4500-5300 cal/g ash-free dry weight) are found in plant parts typically characterized by high metabolic activity, such as leaves, flowers and root nodules. High values are also found in seeds where compact energy storage is adaptive. Lower values (3800-4300 cal/g ash-free dry weight) are found in primarily structural tissues such as stems, roots, inflorescences, empty pods and seed coats Differences among species are found only when the functions or physiological properties of particular plant parts are dissimilar. Thus, the stems of the annuals have lower values than those of the perennials, and the perennial herb, with a lower photosynthetic rate than the annual or shrub, has lower leaf caloric values. Temporal variation in caloric values is found in the annual where there is a gradual translocation of energy from other plant parts to the seeds as the seeds mature and the plant senesces.