CUTICLE THICKNESS AND CHLORPHYLL CONTENT IN BRISTLECONE-PINE NEEDLES OF VARIOUS AGES

Cuticles of 1-yr-old needles (1984) from Great Basin bristlecone pine trees (Pinus longaeva D. K. Bailey) were examined to determine if cuticle thickness was reduced in these high elevation trees. Chlorophyll content and cuticle thickness were also measured on bristlecone pine needles that had been retained for up to 35 years. The 1984 needle cuticle thickness ranged from 5.0 to 9.0-mu-m (xBAR = 6.5), almost double the thickness of those measured on other timberline conifers, and showed no signs of deterioration with increasing needle age. Total chlorophyll content did not decline with increasing needle age, and needles maturing in 1975 were found to have the highest chlorophyll content of any needles examined. It appears that bristlecone pine functions well under harsh environmental conditions and produces long-lived, functional needles.