Planting models and mulching materials management to improve anti-oxidant defense system, grain hormone balance and production of maize in semi-arid regions.

The water shortage and weeds damage have become severe problems in the dry-land farming system of China, the farming commonly using mulching materials strategy as a water-saving and weeds precaution agricultural technology. However, it is still unclear whether various mulching applications under different cultivation models can improve the antioxidant defence system, herbicide tolerance, and grain hormone balance, photosynthetic capacity and grain yield of corn. Therefore, during 2018-2019, a two-year study was conducted, and the following six treatments were used: CT: traditional planting; SM: corn stalk mulch; FM: plastic mulch; RT: ridges cultivation without plastic mulch; RP: Plastic mulch covering ridges and furrows; RPS: Plastic covering on ridges and straw on furrows. The results revealed that the RPS treatment enhanced the soil water storage in the jointing and filling stages, and obtained a higher chlorophyll stability index, IAA, Z + ZR, ABA, corn yield and other plant hormone content, compared with the control plot. Furthermore, this improvement is attributed to the reduction of oxidative damage of malondialdehyde (MDA) content at different growth stages. The RPS and RP treatments considerably improved the superoxide dismutase (SOD) and catalase (CAT), also decreased considerably the MDA, H2O2 and O2- contents at various growth stages. The RPS treatment had a higher ability to reduce the H2O2 and O2-, and the better anti-oxidant enzyme activity due to the lower level of lipid peroxidation, which can efficiently protect the photosynthesis mechanism and significantly improve (54.8%) biomass, (49.5%), WUEg, (89.1%), WUEb and (98.0%) grain yield are higher than CT treatment. In conclusion, RPS treatment has a great potential in improving grain hormone balance, antioxidant defence system and corn production in semi-arid areas.

Seed dressing with mefenpyr-diethyl as a safener for mesosulfuron-methyl application in wheat: The evaluation and mechanisms.

Mesosulfuron-methyl is always applied by foliar spraying in combination with the safener mefenpyr-diethyl to avoid phytotoxicity on wheat (Triticum aestivum L.) cultivars. However, it was observed that the tolerance of Tausch's goatgrass (Aegilops tauschii Coss.) to mesosulfuron-methyl significantly increased in the presence of mefenpyr-diethyl by performing bioassay. This confirmed phenomenon may lead to overuse of mesosulfuron-methyl and weed resistance evolution in field conditions. Therefore, we tested the effect of wheat seed dressing with mefenpyr-diethyl as a possible alternative and disclosed the underlying mechanisms by herbicide dissipation study, enzymatic analysis and transcriptome profiling. The results suggest that increase of ALS activity, enhancement of metabolic processes, and other stress responses are crucial for the regulation of herbicide detoxification induced by mefenpyr-diethyl. Additionally, transcription factors such as AP2/ERF-ERF, bHLH, NAC, and MYB, and protein kinase such as RLK-Pelle_DLSV might play vital regulatory roles. The current study has important implications for mesosulfuron-methyl application in wheat field to control Tausch's goatgrass and provides a comprehensive understanding of the protective effect of mefenpyr-diethyl.