Nondestructive and Rapid Estimation of Leaf Chlorophyll and Nitrogen Status of Peace Lily Using a Chlorophyll Meter

Timely and nondestructive detection of leaf nitrogen (N) status could greatly improve nutrient management practices for greenhouse ornamental production. This study evaluated the feasibility of using a SPAD-502 chlorophyll meter for estimating leaf chlorophyll and nitrogen contents of the peace lily (Spathiphyllum Schott). Three cultivars ‘Claudia’, ‘Double Take’, and ‘Petite’ were grown in a soilless substrate and sub-irrigated with solutions containing N at 50, 100, 200, or 400 mg L−1 through an ebb-and-flow system. The SPAD-502 chlorophyll meter was used to measure leaf greenness. Chlorophyll contents of leaves were also analyzed using the dimethyl sulphoxide extraction method. Total N was determined by a CNS Auto-Analyzer. Correlation analyses showed that coefficients (r 2) between SPAD values and leaf chlorophyll contents were 0.83, 0.77, and 0.73 for ‘Claudia’, ‘Double Take’, and ‘Petite’, respectively, and coefficients (r 2) between SPAD values and leaf N contents of ‘Claudia’, ‘Double Take’, and ‘Petite’ were 0.84, 0.82, and 0.91, respectively. These results suggest that the readings from a SPAD meter can be used for rapidly and nondestructively estimating leaf chlorophyll and N status of the peace lily. As high quality Spathiphyllum were produced at the N concentration of 200 mg L−1, the corresponding SPAD values established in this study could facilitate in situ decision-making on N application for the production of the peace lily.