Foliar SPAD-502 meter values, nitrogen levels, and extractable chlorophyll for red maple selections

Abstract

Twelve red maple selections in an existing field trial were evaluated for leaf chlorophyll content with a SPAD-502 chlorophyll meter, total foliar N concentration with a LECO CHN analyzer, and total foliar chlorophyll content (CHL) by N,N-dimethylformamide extraction. Selections included Acer rubrum L. 'Autumn Flame', 'Fairview Flame', 'Franksred' (Red Sunset(TM), 'Karpick', 'Northwood', 'October Glory', 'Redskin', 'Schlesingeri', and 'Tilford', and A. xfreemanii E. Murray 'AutumnBlaze' ('Jeffersred'), 'Morgan' ('Indian Summer'), and'Scarsen' (Scarlet Sentinel(TM)). 'Franksred' and 'Northwood' had the highest monthly SPAD-502 values in 1993 and 1994. Lowest SPAD-502 values were on 'Redskin' and 'Autumn Blaze' each year. Foliar N concentration ranged from 2.62% for' Autumn Flame' to 2.01% for Redskin. CHL levels on a freshweight basis ranged from 5.38 mg·g-1 for 'Fairview Flame' to 3.94 mg.g-1 for 'October Glory'. SPAD-502 and extractable CHI, values were correlated (r = 0.45; P ≤ 0.001); however, the correlation (r = 0.15; P ≤ 0.38) between SPAD-502 values and total foliar N concentration was nonsignificant.