Application Study Of Hydrogen-rich Water-alleviated Phytotoxicity Of Bispyribac-sodium In Rice

A large number of herbicides are used in order to improve the yield of crops in modern agriculture.Bispyribac-sodium as a pyrimidine salicylic herbicides and highly active acetyl lactate synthase(ALS)inhibitor,is widely used in rice field.In recent years,some studies have found that hydrogen plays an important role in plant stress resistance network as a new signal molecule.However,whether or how hydrogen influences the phytoxicity of bispyribac-sodium is not clear.To resolve this problem,in this study,hydrogen-rich water was used to explore above possibility and corresponding mechanism.Firstly,the Japonica rice(Nipponbare)and hybrid rice(9311)were selected as the experimental materials.The phenotypic changes of rice treated with HRW(as a pretreatment)and Bispyribac-sodium were measured and compared by laboratory bioassay.Meanwhile,the changes of antioxidant defense system and activity of ALS were also studied.Finally,the residual amounts of Bispyribac-sodium in the leaves of two kinds of rice varieties were measured by liquid phase 5 d after stress treatment.The related results are shown as follows:1.Phenotypic changes of rice treated with hydrogen rich water and Bispyribac-sodiumAfter two kinds of rice varieties were stressed with two different concentrations of Bispyribac-sodium(30 g a.i./hm2 and 45 g a.i./hm),both plant height and fresh weight were greatly inhibited;the plant height and fresh weight of Indica rice treated with Bispyribac-sodium were all recovered after 75%HRW was pretreated;the difference between treatment at 50%and 100%HRW and the single treatment of Bispyribac-sodium is not obvious;plant height and fresh weight of Japonica rice at all HRW concentrations have been restored to some extents,and there was no significant difference in root length between all two varieties.Additionally,the results showed that both HRW and Bispyribac-sodium had no obvious effect on the root length of rice.2.Changes of antioxidant defense system and ALS activity in Japonica and Indica rice after HRW treatment.Both the separate HRW and Bispyribac-sodium treatments enhanced antioxidant enzyme activities.Importantly,respect to the stress alone,the antioxidant enzyme activities were significantly higher when the addition of HRW followed by Bispyribac-sodium stress,suggesting that HRW improved rice resistance to Bispyribac-sodium stress.The experiment also confirmed the inhibitory effect of Bispyribac-sodium on ALS activity,while the HRW weakened the inhibition.Most importantly,the rate of ALS enzyme activity degradation in Indica rice was lower than Japonica rice,indicating that Indica rice was more sensitive to the stress.3.Effects of hydrogen rich water on the metabolism rate of double grass in RiceUnder HRW pretreated rice,the metabolic rate of Bispyribac-sodium was improved.After pretreatment with HRW,the residue in Indica rice with Bispyribac-sodium dosage of 30 g a.i./hm2 decreased by 48.68%?51.65%,with an average reduction of 35.77%?43.02%in 45 g a.i./hm;the residue in Japonica rice with 30 g a.i./hm2 reduced by 57.91%?61.20%on average,with an average reduction of 38.68%?44.88%in 45g a.i./hm2.In addition,HRW with different concentration gradients showed no significant difference in promoting the rate of Bispyribac-sodium metabolism in rice.Together,above results showed that HRW might be a potential important approach in the practice of Agricultural field against the phytotoxicity of Bispyribac-sodium.