Measurement of plant leaf physical configuration under water deficit stress using fractal dimension

Three dimensional laser scanning device based on oblique incidence method was used to measure the information of Cucurbita Pepo L. leaf’s original physical configuration. Based on these data, fractal dimension was defined as an indicator of leaf’s wilting degrees. According to measurements of different leaves’ physical configurations (divided into 10 levels), the wilting index defined by fractal dimension and its correlations with soil temperature and illumination intensity were researched. Results showed that under constant field capacity condition, leaf fractal dimension increased monotonously with wilting degrees. Laser scanning was an effective method for obtaining leaf’s physical configuration. Leaf fractal dimension had negative correlation with soil temperature and illumination intensity. A multiple linear regression model of fractal dimension with soil temperature and illumination intensity as two variables was established. Thus leaf’s wilting degrees defined by fractal dimension can be an efficient indicator of plant’s water stress level and can be a valid control variable of water saving system as well.