Cyclocarya paliurus for Phytomanagement of Lead-Contaminated Soils.

Cyclocarya paliurus seedlings were cultivated in three types of lead (Pb)-contaminated soils with Pb concentration of 305 ± 17 mg/kg (T1), 1964 ± 59 mg/kg (T2) and 3502 ± 107 mg/kg (T3), respectively. The results showed that after 180 days of cultivation, the contents of exchangeable and carbonate-bound Pb fractions significantly decreased in T1 and T2, but increased in T3. The growth indices of C. paliurus seedlings decreased with increasing Pb concentration; however, no difference was found between that in T1 and in Pb-free soil. The Pb concentration in the roots was an order of magnitude higher than that in the stems and in the leaves. The bioconcentration factor (BCF) of the leaves was the lowest among the three tissues investigated, and decreased with the higher concentration of Pb in the soils. These results suggest that C. paliurus can be used as a sustainable and profitable plant for the phytomanagement of Pb-contaminated soil.

Morphological and physiological variations of Cyclocarya paliurus under different soil water capacities.

Soil water capacity (SWC) is a very important factor for the artificial cultivation and production of seedling in Cyclocarya paliurus. To understand SWC requirement for seedling cultivation and to investigate morphological and physiological changes under different SWCs, a 100-day SWC treatment was conducted during artificial cultivation; four treatments were 10-20 wt% SWC (W1), 30-40 wt% SWC (W2), 50-60 wt% SWC (W3), and 70-80 wt% SWC (W4). The result showed that W3 was suitable for seedling cultivation. Compared with W3, growth biomass decreased and water content increased at W1, W2 and W4; K, Ca, and Mg content increased under W1, while Na content increased under W4; SOD, PPO, POD, and CAT activity in leaf significantly increased under W1 and W4, of which SOD activity was the highest, and MDA content reached its maximum under W1. W1 and W4 had negative effects on seedling growth, and seedlings adapt to unfavorable water condition by morphological and physiological responses. Our research would be useful for artificial cultivation and management of Cyclocarya species.