ABSTRACT
The characteristics of cadmium (Cd) uptake kinetics in a pollution-safe rice variety of D62B were studied in a hydroponic experiment under different Cd levels and stress time, with a common variety Luhui17 as the control. The results showed that Cd uptake in root of D62B was significantly lower than that of Luhui17 under different stress times. The differences in Cd uptake of the two rice varieties increased with the extension of absorption time. Total Cd amount of Luhui17 was 1.3 times as much as that of D62B when the absorption time was 72 h. Meanwhile, the Cd uptake kinetic of the two varieties accorded to Michaelis-Menten equation, and little difference in Michaelis constants (Km) was observed in the two varieties. However, the maximum uptake rate (Vmax) of Luhui17 was 2 times as much as that of D62B. Once the stress time was more than 48 h, the transfer coefficients of D62B was lower than that of Luhui17, and the Cd distribution ratio in root of D62B was much higher, indicating that D62B had greater accumulation ability in root compared with Luhui17. In conclusion, the Cd uptake and transfer ability of D62B were lower than those of Luhui17.
Subject(s)
Cadmium/pharmacokinetics , Oryza/chemistry , Water Pollutants, Chemical/pharmacokinetics , Environmental Pollution , Kinetics , Plant Roots , Soil PollutantsABSTRACT
The present paper is concerned with computing the multiple scattering characteristics of a sea fog-sea surface couple system within this context. The single scattering characteristics of sea fog were studied by Mie theory, and the multiple scattering of sunlight by single sea fog layer was studied by radiative transfer theory. The reflection function of a statistically rough ocean surface was obtained using the standard Kirchhoff formulation, with shadowing effects taken into account. The reflection properties of the combined sea fog and ocean surface were obtained employing the adding method, and the results indicated that the reflected light intensity of sea fog increased with the sea background.
ABSTRACT
A pot culture experiment was carried out to study the influence of arbuscular mycorrhizal (AM) fungi on the growth and phoxim residue of carrot (Daucus carota L). Four levels of phoxim (0, 200, 400, 800 mg x L(-1)) and two AM fungal inocula, Glomus intraradices BEG 141(141), Glomus mosseae BEG 167 (167),and one nonmycorrhizal inoculum (CK), were applied to the sterilized soil. The plants were harvested after 5 months of growth and phoxim was irrigated into the root zone 14 d before plant harvest. Although decreasing with the increase of phoxim dosage, root infection rates of all the mycorrhizal plants were higher than 70%. Phoxim showed no significant dose effect on shoot wet weights and root yields, which were all increased by AM inoculation at four phoxim dosages. Phoxim residues in shoots and roots increased with the increase of phoxim dosage, but decreased by AM inoculation. In general, Glomus intraradices BEG 141 showed more pronounced effects on the growth and phoxim residue of carrot than Glomus mosseae BEG 167 did. Our results show a promising potential of AM fungi in carrot production and controlling pesticide residues.
