Abstract: The analysis on the characterization of root system architecture would assist to better understand the functional and growth strategies of root systems of rice plants, which is closely related to rice plant’s adaptation to insufficient supply of soil water and nutrient. The fractal analytical method was used to examine the difference of the root systems of four rice genotypes (MADHUKAR, IR8192-200, IR26, and IR8192-31) and the relationship between root length and plant Zn uptake was explored. The root systems were grown for one month in root boxes with 25 cm in length, 2 cm in width and 40 cm in depth, which were filled with soil. The root systems were harvested following the needle-pinboard method, and then spread on the transparent plastic films with nets after carefully washing out the soils. The two-dimensional images of root systems were digitized by using a scan-ner. The digitized images were used for analysis based on fractal geometry with the box-counting method. The fractal parameters differed among the four selected rice genotypes. Variety of MADHUKAR had the greatest values of fractal dimension (FD) and fractal abundance (FA). IR8192-200’s roots had the smallest FD and FA. It was suggested that MADHUKAR had a higher capac-ity of root branch and a larger volume of soils explored by the whole root systems than other three rice genotypes. The FD and FA had significant correlations with total root length. Moreover, the correlation coefficient between FA and total root length was higher than that FD and total root length. The FD and the FA of rice roots were observed to positively correlate with shoot dry weight, shoot biomass per unit of Zn concentration, and Zn accumulation in shoot. However, shoot Zn concentration was negatively correlated with FD and FA. Root configuration changes might affect the growth of rice plants, plant Zn uptake and Zn use efficiency. The fractal analysis of root structure by box-counting method can be used to evaluate root system of different rice genotypes.

Key words: Fractal analysis, Root systems, Rice (Oryza sativa L.), Zn