No abstract

Morus alba L. (mulberry) is a perennial woody tree and a species with great potential for Cd phyremediation owing to its large biomass and extensive root system. The mechanisms involved in Cd detoxification were investigated by analyzing the subcellular distribution and chemical forms of Cd in mulberry in the present study. These results indicated that 53.27-70.17% of Cd mulberry accumulated was stored in the root and only about 10% were in the leaves. Lots of the Cd was located in the cell wall of the mulberry root and in soluble fraction of the mulberry leaf. Moreover, in roots, the largest amount of Cd was in the form of undissolved Cd-phosphate. While in mulberry leaves and stems, most of the Cd was extracted by 2% Acetic acid and 0.6 M HCl, representing Cd-phosphate and Cd-oxalate. It could be concluded that the Cd combination with peptides and organo-ligands in vacuole of leaf or complexed with proteins or cellulose in the cell wall of root might be contributed to the tolerance of mulberry to Cd stress. The mulberry could be used to remediate the Cd polluted farmland soils.

No abstract

In this study, the adsorption behavior of Cd ions by rhizosphere soil (RS) and non-rhizosphere soil (NS) originated from mulberry field was investigated. The Langmuir, Freundlich and the Dubinin-Radushkevich (D-R) equations were used to evaluate the type and efficiency of Cd adsorption. The RS was characterized by lower pH but the higher content of soil organic matter and cation exchange capacity (CEC) as compared to NS. Also, the maximum adsorption of Cd for RS (5.87 mg/g) was slightly bigger than that for NS (5.36 mg/g). In Freundlich isotherm, the K of the adsorption of Cd to surface of the RS components was higher than that of the NS, indicating stronger attraction between Cd and components of the RS. According to the D-R model, the adsorption of Cd by both soils was dominated by ion exchange phenomena. These results indicated that mulberry roots modified physical and chemical properties of the RS under field conditions, which also affected the Cd sorption efficiency by soil components during laboratory experiments. Current knowledge of the Cd sorption processes in the rhizosphere of mulberry may be important if these trees are planted for use in phytoremediation of Cd contaminated soils.

In order to solve the problem that the stem nodes are difficult to identify in the process of sugarcane seed automatic cutting, a method of identifying the stem nodes of sugarcane based on the extreme points of vertical projection function is proposed in this paper. Firstly, in order to reduce the influence of light on image processing, the RGB color image is converted to HSI color image, and the S component image of the HSI color space is extracted as a research object. Then, the S component image is binarized by the Otsu method, the hole of the binary image is filled by morphology closing algorithm, and the sugarcane and the background are initially separated by the horizontal projection map of the binary image. Finally, the position of sugarcane stem is preliminarily determined by continuously taking the derivative of the vertical projection function of the binary image, and the sum of the local pixel value of the suspicious pixel column is compared to further determine the sugarcane stem node. The experimental results showed that the recognition rate of single stem node is 100%, and the standard deviation is less than 1.1 mm. The accuracy of simultaneous identification of double stem nodes is 98%, and the standard deviation is less than 1.7 mm. The accuracy of simultaneous identification of the three stem nodes is 95%, and the standard deviation is less than 2.2 mm. Compared with the other methods introduced in this paper, the proposed method has higher recognition and accuracy.