CIELAB Colour Space Quantification-based Evaluation of Capsule Development and Seed Vigour in Nicotiana Tabacum L

To develop a real-time quantitative method of monitoring capsule development, automatic color space and conductivity meter were used to measure the capsules color parameters and seed vigor, respectively. The results showed that fresh and dry weights of capsules showed an ascending tendency 10 to 20 daysafter pollination, the color parameters b^* and C showed the same tendency during that time. Capsule weight started declining 20 days after pollination, with parameters L^*, b^*, C, h also declining. Water content and color parameters L^* of capsules showed a consistently ascending tendency during the whole development stage from 10 to 50 days after pollination. Correlation analysis showed that there was a significant correlation between capsule fresh weight and all five color parameters (P<0.01). Capsule water content showed a significant negative correlation with color parameter a^* value and positive correlation with L^* and h (P<0.01). Seed germination rate and emergence rate showed significantly negative correlationswith L^*(P<0.05). Regression equations were established respectively asfollows: Y_{fresh weight}=0.579L^*-1.703a^*-0.316b^*+0.499C-0.847h+45.294 (R²=0.910, P<0.05); Y_{water content} =0.907L^*-0.014a^*+0.009h+17.391 (R²=0.892, P<0.05); Y_{germination rate}=0.068 (L^*)² +4.451L^* +24.212 (R²=0.907, P<0.05); Y_{germination rate}=0.064(L^*)²+4.228L^*+23.002 (R²=0.905, P<0.05). CIELAB color space is a quantitative method for color measurement, which could be used to imitate the development of tobacco capsules and predict the change of seed vigor.