Regulation Effect And Mechanism Of Biological Organic Carbon Fertilizer On Crop Growth And Disease Resistance

In recent years,it has become an international research hot-spot that new biological fertilizers have been used to regulate crop growth and induce crop disease resistance.Biological organic carbon（Bio-carbon）fertilizer is a full-water soluble carbon fertilizer which is fully fermented by special high-concentration technology with brown sugar（high-carbon raw materials）,soybeans,plant extracts and other natural resources.Based on the previous researches and in the view of agricultural practice in South China,this thesis focuses on the evaluations on growth regulation of bio-carbon fertilizer on rice,Chinese cabbage and tea,and crop disease resistance induction mechanism.Through full research,it aims to provide a basis and reference for scientifically utilizing new bio-carbon fertilizer and exploring their action mode,which may be contributed to the realization of green control of crop diseases and improvement of agricultural product quality and yield.The main research contents and results are as follows.1.The main components and indicators of the tested bio-carbon fertilizer were analyzed.According to the standard system analysis method such as NY/T 798-2015,the result showed that effective living bacteria of bio-carbon fertilizer（not inactivated）is Bacillus amyloliquefaciens,the bacterial cell density is about 1.87×10⁹CFU/ml.Water as the main carrier accounted for 84.11%,protein,total sugar,total acid accounted for 1.59%,6.60%and 38.85mg/kg,fat,polyphenols,flavonoids,free amino acids accounted for 0.71%,0.2%,0.02%,0.18%,respectively.The acid value is 26.875mg/kg and the main active ingredient is 2-5 carbon organic sugar acid molecules.Total nutrients accounted for 7%of N+P₂O₅+K₂O;mercury,arsenic,cadmium,lead and chromium contents of heavy metals were lower than those specified in NY/T 798-2015.The analysis result indicated the organic matter ratio is about 20%based NY 525-2012 method test.2.The inhibition activities of bio-carbon fertilizer and 8 chemicals,including indole,indoleacetic acid,harmine,4-fluoroindole,5-chloroindole,jinggangmycin,tricyclazole,and pyraclostrobin,were determined by the mycelial growth rate method with reference to NY/T 1156.2-2006 against 4 crop pathogens in vitro,including rice sheath blight fungus,Rhizoctonia solani,rice blast fungus,Pyricularia oryzae,cabbage black spot,Alternaria brassicae,and tea anthracnose,Gloeosporium theae-sinensis.The results showed no remarkable inhibition activity in vitro on these 4 tested crop diseases.The protective activity and treatment activity of bio-carbon fertilizer and 8 compounds against rice sheath blight were determined by potting test method.The protective effects on rice sheath blight were from 21%to 71%when the tested bio-carbon fertilizer was diluted with 500,1000,and 1500 times,which were better than treatment activity.The protective activity treated with bio-carbon fertilizer dilution 500-fold was also equivalent to that with Jinggangmycin100mg/L.Both treatment with 4-fluoroindole and 5-chloroindole have significant inhibitory activity in vitro and treatment activity in vivo on rice sheath blight.3.The effects of bio-carbon fertilizers on rice growth and crop disease resistance induction were studied.The bio-carbon fertilizer could promote the root growth after transplanting rice when sprayed with 500-1500 times dilution 7 days before transplanting.Sprayed with 500-1500-time in 7 days before transplanting,tillering,heading,and filling period,the bio-carbon fertilizer could increase the plant height or promote plant growth,and the rice yield can be increased by 13%-16%.The tested bio-carbon fertilizer also can significantly reduce the incidence rate of sheath blight,R.solani and rice blast,P.oryae by50%-60%.The effect treated with 4 application times throughout the rice growth whold period was significantly better than with pre-emergence treatment only.4.The effects of bio-carbon fertilizer on the growth of Chinese cabbage and the crop disease resistance induction were studied.On the basis of conventional fertilization,the addition of inactivated and non-inactivated bio-carbon fertilizer 5L/667m²as base fertilizer could significantly promote the growth of Chinese cabbage,and the plant height,leaf width,leaf length,and number of leaves and yield were significantly improved.The leaf spot disease index in treatment with bio-carbon fertilize was 20%-30%lower than in control.5.The bio-carbon source fertilizer was studied to regulate the growth of tea and the crop disease resistance induction.When applied of bio-carbon fertilizer with 500-1500-time,the density,length,bud thickness and leaf area of spring tea were significantly better than those in control.The yield of fresh tea can be increased by 25%-43%,reaching the first-class quality standard.No common pesticide residues were detected,and the contents of selenium,iron and sodium were increased by 25%,20%and 248%compared with conventional cultivation.When tea tree treated with 500 times and 1500 times of bio-carbon fertilizer,the incidence index of tea anthracnose,Gloeosporium theae-sinesis,was significantly reduced by 100%and 87.58%compared with CK,respectively.6.The effects of bio-carbon fertilizer on the defense enzyme activity and defensive substance content of crop disease resistance were determined.The application of bio-carbon fertilizer dilution 500 times could significantly increase of the activities of peroxidase（POD）,polyphenol oxidase（PPO）and phenylalanine ammonia-lyase（PAL）in rice,Chinese cabbage and tea,and reduce the content of malondialdehyde（MDA）,as well as increase the total phenolic content.Although the increase in the activities of various enzymes and the trend of change among different crops were different,the increase and decrease of the content of MDA and total phenolic substances are slightly different between different crops,but overall increased activity of these enzymes,reduction of injurious substances,and increase in defensive substances are all beneficial to crops to improve disease resistance.7.Effects of bio-carbon fertilizer on the induced expression of genes associated with rice defense-related resistance were studied.Bio-carbon fertilizer could induce the increased expression of Os NH1-1 and Os PR1 downstream genes of rice defense response,but has no obvious effect on Os PR1O expression.Four salicylic acid-induced resistance genes in rice（Os EDS1,Os PAD4,Os PAL and Os ICS1）showed no significant changes after application of bio-carbon fertilizers.Os LOX,one of jasmonic acid-induced resistance pathway genes,showed no significant changes in the early stage rice while increase in the later stage.On the contrary,the expression of Os AOS2,another gene in jasmonic acid-induced resistance pathway,was increased in the early stage rice,while there was no significant difference from CK in the late stage rice.It is preliminarily believed that the bio-carbon fertilizer induced rice disease defence resistance could be more closely related to JA signaling pathway.