Physiological Responses Of Barely To Herbicide ZJ0273 And Development Of Predictive Model For Physiological Parameters

This paper describes the effect of herbicide ZJ0273 on two barley cultivars Zhenongda 3 and Huangqingluo, which were treated with herbicide ZJ0273 adding in solutions and spraying on leaves. The herbicide effect was investigated on the target site and other important physiological reactions, such as the changes of the content of free amino acid, antioxidant system, photosystem, the pathway of respiration, the activity of glutathione s-transferase which may be the inhibited by herbicide. Furthermore, the models about the barely physiological indicators developed by NIRS were used for monitoring the safety the herbicide to the barley crop.The results showed that the inhibition of the growth of two barely cultivars were significant, the parameters such as the height, fresh weight and dry weight were decreased and the reactive oxygen species content, ASA content, GSH content, MDA content, POD activity, SOD activity, CAT activity, APX activity, GR activity were increased by adding 100 mg/L ZJ0273 into solution. The inhibited effect on the barely growth was mostly relieved by adding exogenous free amino acid, and exogenous 100 and 200 mg/L free amino acid showed better effect. The growth of barely was increased under normal condition by adding exogenous free amino acid, but the reactive oxygen species content was accumulated and the antioxidant system was changed by adding 100 mg/L free amino acid into solution. The reactions were different between free amino acid system of the two barely cultivars under different herbicide concentration treatments. The BCAA and TAA content were increased along with the increasing of treatment concentration and durations of barely Zhenongda 3 and the same changes were observed in barely Huangqingluo except in the primary period (5 days after treatment). The BCAA/TAA of barely Zhenongda 3 was not different under normal condition and under treatment, while Huangqingluo was much affected by treatment than normal condition. There may have been different metabolic mechanisms which caused different changes of free amino acid of two barely cultivars.The inhibited effect was significant on the two barely cultivars in relation to photosynthesis such as Fv/Fm, Y (â…¡) of PSâ…¡with the increase of herbicide treatment concentration and durations. The NPQ of barely Zhenongda 3 was increased during the treatment time. However, the 500, 1000mg/l concentrations caused the NPQ of Huangqingluo to decrease 9 days after treatment, mainly because Huangqingluo did not have enough protection. Meanwhile, the SPAD and Pn of two barely cultivar leaves were significantly declined with the increasing concentrations and no changes were observed with durations.As ZJ0273 worked as ALS inhibitor, it caused the decreased of ALS activity of two barely cultivars especially Huangqingluo,5-9 days after treatment, and the accumulation of pyruvate which was the substrate for synthesizing amino acid. The pyruvate content of Zhenongda 3 was the highest at 7 days after treatment and slightly decreased at 9 days after treatment. While the pyruvate content of Huangqingluo showed increasing trend during the treatment time. The changes of the respiration pathway were different by ZJ0273 treatment. The KCN-resistant respiration rate and total respiration rate were increased and SHAM-resistant respiration rate was declined in the two barely cultivars. The barely AOX activity was induced by herbicide ZJ0273. The AOX activity of Zhenongda 3 was slightly declined at 9 days after treatment and Huangqingluo was increased during the treatment time.In another experiment, both in the two barely cultivars glutathione s-transferase activity was induced by herbicide ZJ0273. The GSTS activity of Zhenongda 3 was increased during the treatment time while the Huangqingluo GSTS activity started to decrease at 20 days after treatment. These changes suggested that GSTS may participate in the ZJ0273 metabolism as there was difference between two barely cultivars.To analyse the effect on barely target site of ZJ0273 and antioxidase by different concentrations during 10-50 days after treatment, it showed ALS activity, BCAA content had negative response to treatment concentration and time while POD activity, SOD activity, MDA content had positive response. To establish the models about barely physiological indicators by the NIRS technology under the herbicide treatment, it showed that the monitoring effects of POD, SOD, MDA, Val, Leu, TAA were better and that of ALS and Ile were much worse. Thus, it can preliminarily be realized to monitor the safety of the herbicide ZJ0273 to crop.