Effects Of Strigolactone Inhibitors On Ratooning Characteristics In Rice

Rice(Oryza sativa L.)is one of the main food crops in China.At present,Couuentional methods to increase rice yield by expanding the acreage under cultivation are limited.In recent years,the net income of traditional double-cropping rice has been low,and the acreage sown has been declining.Increasing multiple cropping index and using growth regulator to promote effective tiller number became one of the key measures for high and stable rice yield.After the harvesting of the first season rice,the dormant buds on the rice piles develop regenerative and effective tillering under suitable conditions,and then head into mature rice,that is,on the basis of the first season and harvest another season to realize the rice system of planting one and reaping two.At present,the main ways to improve the cultivation mode,pile height and the use of growth regulators.Strigolactones(SLs)are novel plant hormones that inhibit plant branching,while SLs inhibitors promote rice tillering.In this paper,the effects of triazole compounds fluridone and pyrazoxyfen on increasing and improving the yield and effective tiller number of two varieties “Yue nong si miao”and “Mei xiang zhan 2” were studied by pot experiment,hydroponic experiment and greenhouse experiment.The main research results are as follows:(1)Through the laboratory potted plant experiment explored the influence of tebutazolol,triadimenol,diphenylpyrimidinol,diniconazole,propionazole,chlorophenylpyrimidinol,pyrazoxyfen,fluridinone eight kinds of triazole compounds on Arabidopsis seedlings and rice seedling growth,the results showed that pyrazoxyfen(2-(4-(2,4-dichlorobenzoyl)-1,3-dimethylpyrazol-5-yloxy)acetophenone)and fluridone(1-Methyl-3-phenyl-5-(3-trifluoromethyl)phenyl)-4(1H)-pyridinone)has significant effects on the growth of Arabidopsis seedlings and rice seedlings,Therefore,pyrazoxyfen and fluridone were selected as candidate compounds for strigolactones inhibitors to carry out subsequent experimental studies.(2)The effects of pyrazoxyfen and furidone on the contents of plant hormone,malondialdehyde(MDA)and activities of superoxide dismutase(SOD)and peroxidase(POD)in rice seedlings were studied by hydroponic experiment in laboratory.In addition to strigolactone,the spraying of pyrazoxyfen and fluridone can alos afferct the branching related phytohormones,it increased zeatin(ZT)in rice leaves and inhibited auxin(IAA)biosynthesis.At the same time,the spraying of pyrazoxyfen and fluridone significantly increased the content of MDA in rice seedlings,affected the antioxidant enzyme system of rice seedlings,and changed the activities of antioxidant enzymes(POD,SOD)in vivo.(3)The effects of pyrazoxyfen and fluridone on the growth and development of ratooning rice were studied by pot experiment in greenhouse.The results showed that the effects of pyrazoxyfen on different pile height and different varieties of ratooning rice had significant differences.For "Mei xiang zhan 2",when the pile height is 15 cm,pyrazoxyfen can significantly promote its growth and effectively improve its yield,which increases by about 10%.For "Yue nong si miao",when the pile height was 30 cm,pyrazoxyfen could significantly promote its growth,and the yield increased to 24.22%.The effects of Fluridone on different pile height and different varieties of rice were significantly different.For "Mei xiang zhan 2",when the pile height was 15 cm,the yield of ratooning rice treated with Fluridone increased by 28%;For "Yue nong si miao",when the pile height was 50 cm,the yield of the ratooning rice treated with Fluridone increased by 21%.At the same time,the application of pyrazoxyfen and fluridone could significantly increase the content of MDA in the leaves of ratooning rice in a short term,and also increase the activities of SOD,POD and other antioxidant enzymes accordingly.Then,under the action of self-protective enzyme system,the effect of Fluridone on the ratooning rice gradually disappeared,and the MDA content,SOD activity and POD activity in the leaves of the ratooning rice gradually decreased and tended to balance.In conclusion,pyrazoxyfen and fluridone can promote the germination and growth of dormant buds as well as significantly improve the yield of ratooning rice under certain conditions,which has a broad application prospect.