Exploring Bamboo Leaf Nutrient Value in the USNPGS Germplasm Collection

Bamboo shoots and leaves are nutritious, providing food for human and animal consumption. However their nutrient value depends on a number of factors including the bamboo species (e.g. taxon), harvesting season and growing location. Leaf crude protein content, amino acid composition and mineral element concentration were quantified from leaf samples collected from 222 accessions representing two bamboo types (temperate/tropical), two growing seasons (dry/wet) and three locations (PGRCU-Byron, GA; TARSMayaguez, PR; and Govardhan Gardens-Mayaguez, PR). Significant variability in leaf nutrient value was identified among accessions, types, growing locations and harvesting seasons. On average, bamboo leaf tissue contained 12.92% protein with relatively high percentages of leucine (Leu, 8.97%) and proline (Pro, 7.98%) and low percentages of tryptophan (Trp, 1.69%) and histidine (His, 2.01%). Bamboo leaves also contained relatively high concentrations of the macro-mineral elements potassium (K, 12.17mg/g) and calcium (Ca, 5.37mg/g), high concentrations of the micro-mineral elements manganese (Mn, 388.76 μg/g) and iron (Fe, 123.19 μg/g), and low concentrations of boron (B, 7.8 μg/g) and zinc (Zn, 28.56 μg/g). PI 647932 and TARS 182857 contained the highest and lowest protein content (21.69% and 5.78%), respectively. Temperate bamboos contained a significantly higher percentage of protein (13.02%) than tropical bamboos (12.71%). Leaf samples harvested from the dry season contained a significantly higher percentage of protein (13.12%) than leaf samples harvested from the wet season (12.70%). The leaf samples harvested from Govardhan Garden location contained a higher percentage of protein (13.40%) than from Byron (12.65%) and TARS (12.89%) locations. The leaf samples harvested from Govardhan Garden contained a significantly higher iron concentration (151.22 μg/g) than from the other two locations (118.19 μg/g, 111.52 μg/g), whereas the leaf samples collected from Byron contained a significantly higher zinc concentration (36.03 μg/g) than what was observed from the other two locations (27.83 μg/g, 22.11 μg/g). There was no significant difference in iron and zinc concentrations between leaf samples collected from dry or wet seasons. Tropical bamboo leaves contained a higher iron concentration (131.74 μg/g) than temperate bamboo leaves (118.95 μg/g), whereas temperate bamboo leaves contained a significantly higher zinc concentration (29.82 μg/g) than tropical bamboo leaves (26.01 μg/g). The information on the bamboo leaf nutrient value related to bamboo accessions, types, growing location and harvesting season will be very useful for bamboo growers, processors and consumers.