[Study of exogenous uniconazole on alleviating low-temperatuer stress of coix seedlings].

The aim of the study is to explore exogenous S3307 on alleviating low-temperature stress of coix seedlings. The coix cultivar, "No 5 Yiliao", was selected as the plant material, through nutrient solution cultivating in greenhouse, the effect of different S3307 concentrations(1, 3, 5, 7, 9 mg·L~(-1)) on coix seedlings traits and physiological indicators were explored under low-temperature stress. The results showed, under low-temperature 5 mg·L~(-1) S3307 could significantly increase coix seedlings stem diameter and biomass, which stem diameter and above-ground biomass, low-ground biomass separately were enhanced 11.90%, 13.59%, 10.99%. Leaf width and lateral root number separately were enhanced 7.63%, 37.52%. Meanwhile, addition of 5 mg·L~(-1) S3307 could significantly reduce relative conductivity and MDA, separately being reduced 23.33%, 17.42% compared to CKL. S3307 could also significantly increase soluble sugar and proline content, which leaf soluble sugar and proline content separately were enhanced 17.16%, 11.87%, which root soluble sugar and proline content separately were enhanced 20.00%, 33.42%. Additionally, S3307 could alleviate the cells destroy in ultra-structure level by improving cell membrane structure and chloroplast capsule layer structure. 5 mg·L~(-1) S3307 could enhance the low temperature tolerance of coix seedlings by regulating the growth and physiological indexes, and thus alleviate the damage caused by low-temperature to the coix seedlings.

Chromium removal capability and photosynthetic characteristics of Cyperus alternifolius and Coix lacryma-jobi L. in vertical flow constructed wetland treated with hexavalent chromium bearing domestic sewage.

In this study, the chromium removal capability and photosynthetic capacity response of plants were investigated in vertical flow wetland microcosms (VFWM) treated with Cr(VI) bearing domestic sewage. Two plants, Cyperus alternifolius (C. alternifolius) and Coix lacryma-jobi L. (C. lacryma-jobi L.) grown in the VFWM enhanced the purification of Cr(VI) enriched domestic sewage. Cr concentration in the effluent fell below detection limit (<0.03 mg L-1), except for the C. alternifolius wetland treated with 40 mg L-1 Cr(VI). The biomasses of both plants species were increased at 10 and 20 mg L-1 Cr(VI) exposure but inhibited at 40 mg L-1 Cr(VI). The photosynthetic capacities of both plants were not affected at 10-40 mg L-1 Cr(VI) exposure during the days 20-60. However, they were inhibited significantly (P < 0.05) at 40 mg L-1 Cr(VI) exposure during days 80-100. These results demonstrated that a VFWM with C. alternifolius and/or C. lacryma-jobi L. was capable of maintaining its efficiency and recovering its vegetation. VFWM with C. alternifolius and/or C. lacryma-jobi L. was promising for purifying wastewater which contains low to medium concentrations of Cr(VI) (<20 mg L-1).