Application of system identification to diagnosis of recovery of root from transplanting injury.

摘要

Foliage plants grown in hydroculture are popular in the office and home. During transplanting from soil to hydroculture, plant roots are injured and plants require time to recover from this damage. A method to diagnose when roots of Schefflera cv. Hong Kong had sufficiently recovered from transplanting injury was developed based on transpiration and variations in stem diameter. Plant responses to light intensity were measured. In a step response test, light intensity was increased from 0 to 120 鍱m-2 s-1 to produce step input. In a variation test, light intensity was changed according to a pseudo random signal (M sequence). Cross-correlation functions of light intensity and plant responses were calculated. Transpiration approached levels observedbefore transplanting 3-4 weeks after transplanting. Time lags associated with light-induced changes of stem diameter of plants (top, middle and all of stem) approached values observed before transplanting 4, 7 and 8 weeks, respectively, after transplanting. It was suggested that plants had recovered from transplanting injury when time lags associated with light-induced changes in stem diameter approached the pre-transplanting values.