| Tartary buckwheat is an important staple crop in our country and has a relatively strong edible and medicinal value.Compared with the conventional Tartary buckwheat varieties,thin shell Tartary buckwheat has the characteristics of thin shell and easy to shelled,which can preserve the nutrients and medicinal ingredients in Tartary buckwheat to a greater extent during processing.However,thin shell Tartary buckwheat has the characteristics of long growth period and low yield,so it is difficult to popularize in production.In order to determine the effects of fertilizer and exogenous hormone treatment on yield and quality of Tartary buckwheat.In this experiment,the thin crust Tartary buckwheat variety ’Miku18’ was used as experimental material.The effects of different concentrations of nitrogen,phosphorus,potassium fertilizer,exogenous GA and naphthylacetic acid(NAA)on grain filling dynamics,starch synthesis enzyme activities,leaf antioxidant enzyme activities,root morphology and physiology,rhizosphere soil available nutrients and enzyme activities,and final yield of thin crust Tartary buckwheat were studied.In addition,the effects of exogenous gibberellin(GA3)and its inhibitor(CCC)on shell formation and quality of Tartary buckwheat fruits were studied by using ’Jinbuckwheat No.2’,’millet buckwheat’ and’Miku18’ as experimental materials.The main results were as follows:(1)Effects of different nitrogen treatments on grouting characteristics and yield of Tartary buckwheatFour treatments,CK(no nitrogen fertilizer treatment),LN(low concentration nitrogen fertilizer,50 kg/hm2),MN(medium concentration nitrogen fertilizer,100 kg/hm2),HN(high concentration nitrogen fertilizer,150 kg/hm2),were used in this study.Its effects on grain filling characteristics,starch synthetase activities,antioxidant oxidase activities of leaves,rhizosphere soil available nutrients and soil enzyme activities,root morphology and vigor,agronomic characters and yield of Tartary buckwheat were studied.The results showed that the initial filling potential(R0),maximum filling rate(Gmax)and average filling rate(Gmean)of Miku18 grains under MN treatment were the highest,and the time to reach the maximum filling rate(TMAX.G)was the lowest.With the increase of nitrogen application rate,the activities of adenosine diphosphate glucose coke phosphatase(AGPase),soluble starch synthetase(SSS),superoxide dismutase(SOD),peroxidase(POD)and soil enzyme activities in Tartary buckwheat grains increased firstly and then decreased.Soil available phosphorus,available potassium,organic matter,root morphological index and root activity,1000-grain weight,grain number per plant,grain weight per plant and yield increased first and then decreased,and the highest value was found in MN treatment.The content of ammonium nitrogen in rhizosphere soil was the highest under HN treatment.(2)Study on grouting characteristics and yield of Tartary buckwheat with different phosphorus fertilizer treatmentsThin shell Tartary buckwheat variety ’Miku18’ as the test material,set CK(no phosphate fertilizer treatment),LP(low concentration phosphate fertilizer 40 kg/hm2),MP(medium concentration phosphate fertilizer 80kg/hm2),HP(high concentration phosphate fertilizer 120kg/hm2)a total of four treatments,Its effects on grain filling characteristics,starch synthetase activities,antioxidant enzyme activities of leaves,rhizosphere soil available nutrients and enzyme activities,root morphology and vigor,agronomic characters and yield of Tartary buckwheat were studied.The results showed that R0,Gmax and Gmean of Tartary buckwheat were the largest and TMAX.G was the lowest under MP treatment.The activities of grain AGPase,SSS,SOD,POD and soil enzyme in Tartary buckwheat increased first and then decreased with the increase of phosphate fertilizer application concentration,and the activity of MP treatment was the highest.Soil ammonium nitrogen,available potassium,organic matter,root morphological index and root activity,1000-grain weight,grain number per plant,grain weight per plant and yield increased first and then decreased,and MP treatment was the highest.The content of available phosphorus in rhizosphere soil was the highest under HP treatment.(3)Study on grouting characteristics and yield of Tartary buckwheat with different potassium fertilizer treatmentsUsing thin shell Tartary buckwheat variety ’Miku18’ as the test material,four treatments were set up: CK(no fertilization treatment),LK(low concentration potassium fertilizer 4kg/hm2),MK(medium concentration potassium fertilizer 8kg/hm2),HK(high concentration potassium fertilizer 12 kg/hm2).Its effects on grain filling characteristics,starch synthetase activities,antioxidant enzyme activities of leaves,rhizosphere soil available nutrients and enzyme activities,root morphology and vigor,agronomic characters and yield of Tartary buckwheat were studied.The results showed that R0,Gmax and Gmean of Tartary buckwheat were the largest and TMAX.G was the lowest under MP treatment.With the increase of potassium fertilizer concentration,the activities of grain AGPase and SSS,SOD and POD in leaves and soil enzyme in Tartary buckwheat were increased first and then decreased,and the activity of MK treatment was the highest.Soil ammonium nitrogen,available phosphorus,available potassium,organic matter,root morphological index,root activity,1000-grain weight,grain number per plant,grain weight per plant and yield increased first and then decreased,and the highest value was found in MK treatment.The content of available potassium in rhizosphere soil was the highest under HK treatment.(4)Study on grouting characteristics and yield of Tartary buckwheat with different concentrations of exogenous NAAThe thin shelled Tartary buckwheat variety ’Miku18’ was used as the test material.The effects of different concentrations of exogenous NAA(0,50,100,150,200,250 mg/L)on grain filling characteristics,starch synthetase activities,leaf antioxidant enzyme activities,rhizosphere soil available nutrients and enzyme activities,root morphology and vigor,agronomic characters and yield of Tartary buckwheat were studied.The results showed that R0,Gmax and Gmean were the highest and TMAX.G was the lowest in 5d-25 d after spraying 150 mg/L NAA at the beginning and full flowering stages.With the increase of NAA application amount,the activities of AGPase and SSS in Tartary buckwheat grains,SOD and POD in leaves and soil enzyme activities increased first and then decreased,and the highest activity was achieved under the treatment of 150mg/L exogenous NAA.Soil nutrient content,root morphological indexes,plant height,number of main stem nodes,number of main stem branches,grain weight per plant and 1000-grain weight basically increased at first and then decreased,and all indexes were highest under exogenous NAA treatment of 150 mg/L.Exogenous NAA could increase the yield of Tartary buckwheat in thin shell to a certain extent,and the yield of 50,100,150,200 and 250mg/L could increase by 1.05,1.07,1.15,1.11 and1.01 times compared with the control,respectively.In conclusion,suitable exogenous NAA treatment of Tartary buckwheat grains can delay the aging of Tartary buckwheat grains,promote the grain filling of Tartary buckwheat grains,promote the root growth,improve the absorption and utilization of soil nutrients,increase the grain weight and yield,and the effect of 150mg/L treatment is the best.(5)Effects of different concentrations of exogenous GA3 on grouting characteristics and yield of Tartary buckwheatThe effects of exogenous GA3 treatment at different concentrations(0,50,100,150,200,250 mg/L)on grain filling characteristics,starch synthesis enzyme,antioxidant enzyme activities,soil characteristics,root morphology,root vigor,agronomic characters and yield of Tartary buckwheat ’Mikuu 18’ were studied.R0,Gmax and Gmean of Tartary buckwheat were the highest and TMAX.G was the lowest in 5 to 25 days after spraying 100 mg/L GA3 at the beginning and full flowering stages.With the increase of GA3 application amount,the contents of AGPase,SSS enzyme activity,antioxidant enzyme activity of leaves,soil enzyme,soil nutrient content,root activity,main stem diameter,grain weight per plant and 1000-grain weight of Tartary buckwheat seeds firstly increased and then decreased,and the highest indexes were obtained under the treatment of 100 mg/L exogenous GA3.The yield of Tartary buckwheat in the treatment of 50,100,150 and 200 mg/L was increased by 1.28,1.61,1.13 and 1.08 times compared with the control,and that in the treatment of 250 mg/L was decreased by 0.60.In conclusion,the suitable treatment of Tartary buckwheat with exogenous GA3 can delay the aging of Tartary buckwheat,promote the grouting of Tartary buckwheat,increase the grain weight and yield of Tartary buckwheat,and the treatment of 100mg/L has the best effect.(6)Effects of exogenous GA3 on shell formation of Tartary buckwheatIn order to clarify the effect of exogenous GA3 on the formation of Tartary buckwheat fruit shell,the Tartary buckwheat variety ’Miku18’,its mother Tartary buckwheat ’Mi buckwheat’ and its father Tartary buckwheat ’Jin buckwheat No.2’ were used as experimental materials.Exogenous gibberellin(0,50,100mg/L)and gibberellin inhibitor(0,50,100mg/L)were applied in different concentrations.The agronomic characters and yield of starch hydrolase,cellulose,sucrose synthetase in Tartary buckwheat seed were analyzed.The results showed that the cellulose content,sucrose synthase(SS),phosphosucrose synthetase(SPS)activities and plant height of three Tartary buckwheat varieties were the highest and ’Miku18’ was the lowest after the application of exogenous hormones at the beginning and full flowering stages with the increase of exogenous gibberellin concentration.Basically,the content of exogenous GA3 was the highest under 100 mg/L treatment,and showed a trend of gradual decrease with the increase of the concentration,and the content of CCC was the lowest under 100 mg/L treatment.With the increase of gibberellin concentration,the quality of Tartary buckwheat increased,plant height,grain number per plant,1000-grain weight and yield all increased.Under the effect of spraying dwarf Chuang grain,the number of branches of main stem increased,but plant height,grain number per plant,1000-grain weight and yield all decreased to some extent.In conclusion,the α-amylase activity in Tartary buckwheat leaves,sucrose content and sucrase activity in Tartary buckwheat grains can be increased under suitable GA3 treatment,which leads to the increase of cellulose content. |
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