Applying Dickson Quality Index, Chlorophyll Fluorescence, and Leaf Area Index for Assessing Plant Quality of Pentas lanceolata

Plant quality greatly relates to the seedling vigor (SV), survival and growth of plants after transplantation. The objective of this study was to use the nondestructive measurements of chlorophyll fluorescence (ChlF) and leaf area index (LAI) as SV indices for star cluster (Pentas lanceolata). Plants were grown in potting soil under nature sunlight for 90 d. A total of 13 morphological and physiological parameters were selected for measurements. Among them, root growth potential (RGP) was the best predictor for SV in all tested plants. Plants were separated into 5 RGP groups based on the number of new roots, and remaining parameters were also separated into those same levels. The trends and rates of increase from levels 1 to 5 in Dickson quality index (DQI), LAI, total dry mass, and ChlF were all similar to the RGP index. Although RGP and DQI are frequently used as indices for SV, these measurements are time-consuming and require sample destruction. Consistent and strongly high correlations were observed among DQI, LAI, and ChlF, demonstrating the applicability of these indices for measuring SV in star cluster. The measurements of LAI and ChlF were predicted using multiple variables from validation datasets, and showed novel and useful parameters for examining the SV of star cluster.