Screening Of Rice Pre-Harvest Sprouting Inhibitors And Initial Study On Inhibitory Mechanism

The problem of rice Pre-harvest sprouting has been increasingly prominent in recent years,endangering the agricultural economy and food security,and it is critical to alleviate the phenomena of Pre-harvest sprouting.Spraying Pre-harvest sprouting inhibitor during the filling period of cereal crops can effectively delay seed germination with no significant effect on crop yield,and is the most ideal way to delay Pre-harvest sprouting phenomenon with low production cost compared to the commonly used plant hormone ABA.As a result,it is critical to create a feasible Pre-harvest sprouting inhibitor combination and examine the mechanism of inhibition.In this experiment,five germination inhibitors were evaluated with the southern easy Pre-harvest sprouting J88 to find the optimal inhibitor combination.We also looked at how the combination of inhibitors affected the physiological and biochemical processes of seed germination and gene expression,and we examined the inhibition mechanism,which has practical implications for reducing the phenomenon of preharvest germination of rice and enhancing rice yield and quality.The results of this research were as follows:(1)When Eugenol,Coumarin,CIPC,MH,and 1-naphthaleneaceticacid methyl acetate were compared for their ability to inhibit rice seed germination,it was discovered that each one inhibited germination to a different extent,and that the inhibitory effect was proportional to the inhibitor concentration;Compared to the control,the inhibitory impact of 1000 mg/L Eugenol on rice seed germination was not substantial,and it might be used in conjunction with other inhibitors;100 mg/L Coumarin significantly inhibited rice seed germination;Although CIPC greatly decreased rice seed germination,its usage was prohibited by Turkey’s Ministry of Agriculture and Forestry due to safety concerns and was discontinued;MH concentrations more than 20 mg/L can considerably reduce rice seed germination,yet the dosage did not exceed the national limit;40 mg/L 1-naphthaleneaceticacid methyl acetate hindered the underground component of the seeds,causing root shortage and severely damaging seed viability,and was eliminated.Six sets of inhibitor combinations were set up to compare the inhibitory effects of different inhibitor combinations on seed germination by using MH as the main reagent in the inhibitor combination,which had the best inhibitory effect and the lowest production cost,and finally determining 20 mg/L MH and 100 mg/L Coumarin as the Pre-harvest sprouting inhibitor combination.(2)Preliminary research into the effect of the inhibitor combination on the physiology,biochemistry,and gene expression of rice seeds during germination revealed that the inhibitor combination significantly inhibited α-amylase activity and thus reduced the soluble sugar content as germination time progressed;By tissue staining localization,the staining intensity of the seeds treated with this inhibitor combination was found to be weaker before 48 h of seed germination compared to the control,indicating that it inhibited the production and accumulation of ROS in the early stage of seed germination,while the staining intensity deepened rapidly after 48 h of germination,which was the opposite of the pre-staining results,which could be related to the disruption of the ROS.To test the hypothesis,the MDA content and antioxidant enzyme system activity were examined further.It was discovered that the combination of inhibitors caused an increase in SOD activity and a decrease in POD activity at the late stage of seed germination,resulting in a disruption of the antioxidant enzyme system and a significant increase in MDA content;RT-PCR examination of important genes during rice seed germination revealed that the inhibitor combination dramatically reduced the expression of α-amylase genes,ABA catabolic genes,and ROS generation genes.In this study,the Pre-harvest sprouting inhibitor was identified as a combination of 20 mg/L MH and 100 mg/L Coumarin,and the inhibition mechanism was examined to offer a foundation and theoretical reference for the study of similar Pre-harvest sprouting inhibitors.