Modeling transpiration and water use of ornamental plants during shipping and storage

Abstract

Experiments were conducted to predict transpirational water loss and duration of shipping/storage of Chrysanthemum morifolium under different temperatures and initial soil water levels. Transpiration rate, water potential, amino acid leakage, plant quality and growth rate following storage were measured. Transpiration rate of Chrysanthemum morifolium showed a quadratic and linear relationship with storage temperature and initial soil water content, respectively. The lowest transpiration rate was observed in the plants stored between 15° and 20°C. Stepwise multiple regression analysis indicated that storage temperature was the major factor which explained the major portion of variability in transpiration (R² = 0.77) Addition of soil relative water content (RSWC) into the model slightly improve the overall model for transpiration. Coefficient of determination (R²) for the final model was 80. The data also suggested that leaf area and soil water content at saturation could be predicted with linear models from leaf number (R² = 0.79) and soil dry weight (R² = 0.99), respectively as independent variables. Storage temperature and duration significantly affected the amino acid leakage, plants quality, and growth during and after storage. Temperatures above 25°C significantly reduced the quality of plants after storage. Plants stored at 25°C showed the highest etiolation during storage, while temperatures below 15°C did not cause significant etiolation. The results indicated that temperatures below 15°C did not significantly affect subsequent growth rate after storage duration up to 8 days. Storage temperatures of 20°C and above caused a significant reduction in subsequent growth rate after 2 days in storage. The growth rate and quality during storage, subsequent growth after storage, and amino acid leakage indicated that the shipping duration model is only applicable to a temperature range of 5° to 15°C. Temperatures above 20°C caused significant quality reduction in the storage. Temperatures induced damages that are independent of water stress prevent the use of the prediction model at high storage temperatures.