Assay dependence of concentration responses to Terminalia leaf and bark extracts in four food crops

Abstract Early-growth bioassays are widely used to screen tree–crop interactions, but their interpretation depends on exposure, endpoint and assay context. We analysed replicate records for leaf and bark extracts of Terminalia bellirica and Terminalia chebula applied to four food crops at 2, 5 and 10% mass per volume after 24, 48 or 72 h extraction. The dataset contained 864 treated records and 96 controls, with four complete outcomes. Contrasts among extract treatments avoided uncertain control sharing, while heterogeneous-variance intervals, multiplicity adjustment and exact single-record deletion assessed uncertainty and influence. Increasing concentration from 2 to 10% reduced laboratory root length by 46.14% for T. bellirica and 48.87% for T. chebula , compared with 3.24% and 15.94% in pots. Pot T. chebula germination declined by 11.39 percentage points on the nominal seed denominator while dry mass increased by 11.86%. Aggregate pot shoot-length increases did not survive multiplicity adjustment. Extending extraction from 24 to 72 h reduced pot germination by 6.00 and 6.89 percentage points, respectively. These results identify endpoint discordance and assay-dependent concentration responses rather than a universal crop-tolerance ranking. Laboratory and pot endpoints differed in age and medium, and inference remains conditional on the independence of the source replicate records. The analysis provides a reproducible basis for prioritising matched-exposure follow-up, without establishing chemical causation or field compatibility.