Different Influence Factors On Growth And Flavor Quality Of Chinese Chive Under Water Culture Condition

Leeks are herbaceous plants grown throughout the country.With the rise and rapid development of soilless cultivation in China,leek cultivation has gradually shifted from soil cultivation to hydroponics,which shortens the growing time of leeks and reduces the flavour quality of leeks due to high harvest frequency.In this work,we used leek cultivar’791’as test material to analyse the effects of different concentrations of nutrient solutions,glutamate concentrations,light quality LED and the ratio of red and blue light on the growth and flavour quality of hydroponic leeks and to determine the best environmental conditions for leek growth,thus providing a theoretical basis for improving the flavour quality of hydroponic leeks.The results of the specific experimental studies are as follows.1.to investigate the effects of nutrient solution concentration on leek growth and flavour quality.Nutrient solution concentrations of T1=1.5 m S-cm^-1,T2=2.0 m S-cm^-1,T3=2.5 m S-cm^-1,T4=3.0 m S-cm^-1,T5=3.5 m S-cm^-1,T6=4.0 m S-cm^-1,T7=4.5 m S-cm^-1and seven different EC values were set.Increasing the concentration of the nutrient solution within a certain range increased both plant height and yield of the leek.The Vc content and soluble protein content were highest in the T4 treatment,soluble sugar content was highest in the T5 treatment,total phenolic content was highest in the T1treatment,flavonoid content was highest in the T5 treatment,enzymatic pyruvate content was highest in the T1 treatment,and nitrate-nitrogen and cellulose content were lowest in the T1 treatment.A comprehensive analysis showed that EC values between 2.0 and 3.0m S-cm^-1 is the suitable concentration range of the nutrient solution for the growth of leeks in hydroponics.2.to investigate the effect of exogenous glutamic acid on the growth and flavour quality of leeks.Six glutamic acid concentrations of 0 mmol-L^-1,0.25 mmol-L^-1,0.5mmol-L^-1,1.0 mmol-L^-1,2.0 mmol-L^-1 and 4.0 mmol-L^-1 were determined.The results showed that plant height,yield,free amino acids,Vc,soluble sugar,enzymatic pyruvate and nitrate-nitrogen content of leek first increased and then decreased;chlorophyll a,chlorophyll b,chlorophyll a+b and soluble protein content gradually decreased;total phenols,flavonoids and cellulose content first decreased and then increased;at the concentration of 0.25 mmol-L^-1,W5S The relative conductances of W5S,W1W and W2W were higher and taste performance was better at 0.25 mmol-L^-1.In a comprehensive analysis,it is recommended to use 0.5～1.0 mmol-L^-1 for cultivation in leek production to achieve higher taste quality.3.The effects of white light,red light,blue light and green light on the growth and flavor quality of hydroponic leek were investigated.The results showed that compared with white light treatment,red light increased plant height,yield,root activity,total phenol,flavonoid,nitrate nitrogen and cellulose content,and inhibited pseudo stem diameter,leaf number,shoot fresh weight and chlorophyll synthesis.Blue light promoted leaf width,increased Vc content,soluble protein content,and inhibited dry matter accumulation of Chinese chives.Green light promoted the internode length and enzymatic pyruvate content,and inhibited the yield and chlorophyll synthesis.The relative conductivity values of W5S,W1W and W2W are higher under blue light treatment.Comprehensive analysis,in the leek production,it is recommended to use blue light treatment for cultivation,to achieve higher yield,quality and flavor.4.investigating the effects of the ratio of red and blue light on the growth and flavour quality of leeks.A treatment with white light as control and five different ratios of red and blue light were established:T1（white light）,T2（R:B=1:1）,T3（R:B=3:1）,T4（R:B=5:1）,T5（R:B=7:1）and T6（R:B=9:1）.As the ratio of red light in the red-blue light ration increased,the plant height,yield,nitrate nitrogen and cellulose content of the leek gradually increased;the total phenolic content,flavonoid content and root vigour gradually decreased as the ratio of red light increased;pseudo stem thickness,leaf number,lower soil fresh weight,chlorophyll content,Vc content,soluble content,soluble protein content and cellulose content of leek gradually increased and then decreased.The trend of increasing and then decreasing pseudo-stem thickness,leaf number,fresh weight of lower soil,chlorophyll content,Vc content,soluble sugar content,soluble protein content and fiber content of leek.In a comprehensive analysis,it is recommended to use the treatment groups T3（R:B=3:1）to T5（R:B=7:1）for leek cultivation to achieve higher yields and better taste quality.