To investigate the effects of intercropping and applying Pterocypsela laciniata straws on potassium uptake of grape seedlings, this pot experiment was conducted to set up five treatments under selenium stress. From the results, the content of total K in parts of plants was different. In plants, the content in leaf was higher than that in root or stem. Among five treatments, applying P. laciniata straws always decreased the total K content in plants. Furthermore, intercropping with P. laciniata seedlings could increase the content in stem, leaf and shoot of grape seedlings. So the results showed that applying root, stem and leaf straws of P. laciniata could not improve nutrient accumulation or the growth of grape seedlings. But for the available K content, it was on the increase by intercropping and applying straws. Among them, applying stem straw of P. laciniata made the content higher. Although there was higher available K content in soil by applying straws, the total K content in plants was lower. Thus, applying P. laciniat a straws was not effective on the growth of grape plant.

The effects of different concentrations of selenium (0.00, 0.05, 0.10, 0.25, 0.50, 1.00, 2.00 mg/L) on the stress resistance of grape seedlings were studied by pot experiment. The results showed that the proline content in different parts of grape seedlings showed an increasing trend with the increase of selenium concentration. The activities of SOD, POD and CAT, as well as the relative conductivity, malondialdehyde and soluble protein content of grape seedlings increased first and then decreased with the increase of exogenous selenium concentration. When the concentration of selenium was 0.50 mg/L, the antioxidant enzyme activity and the content of permeate in grape seedlings reached the maximum. In summary, low concentration of selenium can effectively improve the stress resistance of grape seedlings, but when the concentration of selenium is higher than 0.50 mg/L, it has a toxic effect on grape seedlings.

The experiment aimed to study the effects of abscisic acid on soluble sugar content of Perilla frutescens seedlings under cadmium stress. The leaves of P. frutescens were foliage sprayed with different concentrations (0, 1, 5, 10, 20 μmol·L −1 ) of ABA under cadmium stress (10 mgkg −1 ). The results showed that the soluble sugar content in root, stem and shoot increased with the ABA concentration increasing at first, and then decreased. The soluble sugar content in leaf decreased with the ABA concentration increasing. The soluble sugar content in root and stem peaked when the ABA concentration was 5 pmol-L −1 , which increased by 8.11% and 19.87% compared to the ABA concentration was 0 pmol-L −1 , respectively. And the soluble sugar content in leaf peaked when the ABA concentration was 1 pmol-L −1 , which increased by 1.04%. In conclusion, appropriate concentration of ABA could increase the soluble sugar content of P. frutescens under cadmium stress, and alleviated the stress of cadmium on P. frutescens seedlings to some extent.

The effects of mulching with four hyperaccumulator plants Crassocephalum crepidioides , Galinsoga parviflora , Youngia japonica , and Gnaphalium affine straws on soil enzyme activity of grape seedlings under cadmium (Cd) stress were studied by a pot experiment. The results showed that mulching with four kinds of hyperaccumulators straws, the soil catalase, phosphatase and sucrase activity were increased compared with the monoculture. Only the straw-mulch Y. japonica decreased the soil urease activity, which decreased by 0.10%, and others treatments all increased the soil urease activity. In conclusion, the treatment of G. affine is the best, C. crepidioides followed it.

The pot experiment was conducted to study the effects of soluble sugar content of grape seedlings under selenium stress by intercropping and the application of straws in soil. There were five treatments: grape seedlings monoculture; intercropping with Pterocypsela laciniata and applying leaf, stem and root straws of P. laciniata in soil with grape seedlings, respectively. By analyzing, the results displayed that the soluble sugar content in root and stem was markedly lower than that in leaf and shoot. In five treatments, intercropping was significantly increased the soluble sugar content compared with the control. It promoted the growth and the nutrient substance of P. laciniata. On the contrary, applying root, stem and leaf straws of P. laciniata in soil reduced the soluble sugar content of grape seedlings. Obviously, applying P. laciniata straws could not improve the growth of P. laciniata. The content of soluble sugar was always ranked as: grape seedlings intercropping with P. laciniata seedlings > grape seedlings monoculture > applying the leaf straw of P. laciniata in soil with grape seedlings > applying the stem straw of P. laciniata in soil with grape seedlings > applying the root straw of P. laciniata in soil with grape seedlings. In a word, intercropping with P. laciniata seedling was a best treatment for improving the growth of grape seedlings compared to applying P. laciniata straws.

In the experiment, the leaves of Perilla frutescens were foliage sprayed with different concentrations (0, 1, 5, 10, 20 μmol·L −1 ) of abscisic acid (ABA) under cadmium stress (10 mg·kg −1 ). The results showed that compared with the total phosphorus content in root, stem, leaf and shoot, when the ABA concentration was 5 μmol·L −1 , the total phosphorus content in corresponding organs increased by 112.07%, 17.74%, 13.89% and 15.01%. In conclusion, appropriate concentration of ABA could increase the total phosphorus content of various organs of P. frutescens under cadmium stress, and the concentration of 5 μmol·L −1 was the most suitable.