Research On Wasabi Plant Hydroponics Technology

Wasabi is a precious spice plant,known as "green gold".Wasabi plants in China are mainly planted in soil,and have problems such as long planting cycles,severe damage from soil pests,large labor input,and land rotation.Plant hydroponics is an important technical means for the development of modern agriculture.The use of hydroponics to grow wasabi has many advantages and is suitable for industrial development.But there is less research on wasabi hydroponic cultivation.Therefore,this paper used Nutrient Film Technique and used wasabi seeds as materials to screen the optimal temperature and treatment methods for seed germination.The research on hydroponics technology of wasabi seedlings was conducted based on plant height,leaf area,biomass,leaf chlorophyll Content and photosynthesis parameters were used as indicators to screen the formula and concentration of nutrient solution suitable for the growth of wasabi seedlings;the effect of adding different nitrogen,phosphorus and potassium concentrations in nutrient solution on the biomass and flavor isothiocyanate of wasabi plants was researched.The hydroponic cultivation technology system of wasabi plant was established.The main results were as follows:1.Rapid germination test of hydroponic wasabi seeds showed that wasabi seeds were germinated with hydroponic sponge as the substrate.The seeds were treated with 0.2 g·L^-1 of GA3 solution for 30 minutes and germinated at 20 ℃.The germination rate was 93.33 % after 14 days The survival rate of wasabi hydroponic seedlings after planting was above 95 %.2.Nutrient solution formula screening test showed that using wasabi seedlings that grew the first euphylla as materials,and after being cultivated in four nutrient solutions for 60 days,it was observed that each nutrient solution was better than those without nutrient in clear water（control group）.The formula Ⅱ nutrient solution is the most beneficial for the growth of wasabi seedlings.After 60 days of cultivation,its plant height is 17.06 cm,leaf area is 60.88 cm²,biomass is 14.25 g,and leaf chlorophyll content is 1.96 mg·g^-1,with a net photosynthetic rate of 9.75 μmol·m^-2·s^-1.3.The nutrient solution concentration screening test showed that wasabi seedlings that had just grown the first euphylla were used as materials,and were treated with four concentrations of 1/4,1/2,1,3/2 times of Formula II,After 60 days,the growth of wasabi seedlings cultivated with different concentrations of nutrient solutions were all better,when compared to wasabi seedlings cultured in water without nutrients addition.With the increase of the nutrient solution concentration,the plant height,leaf area and biomass of the wasabi showed a trend of first increase and then decrease.After 60 days of cultivation,the plant height is 18.92 cm,the leaf area is 69.73 cm²,the biomass is 16.91 g,the leaf chlorophyll content is 2.11 mg·g^-1 and the net photosynthetic rate is 11.04 μmol·m^-2·s^-1.4.In order to ensure wasabi yield and quality,wasabi plant with uniform growth a plant height of（20±1）cm were selected as the materials,1/2 times the formula Ⅱ as the basic nutrient solution,and four different concentrations of nitrogen,phosphorus and potassium were subjected to a single factor screening test.After 120 days of cultivation,it was found that different nitrogen,phosphorus,and potassium concentrations had different effects on hydroponic wasabi plant growth and isothiocyanate content.Nitrogen concentration screening test showed that 5 mmol·L^-1 nitrogen concentration culture is beneficial to the growth of wasabi plants,and can significantly increase the biomass of the above ground part.Its plant height is 42.55 cm,and the fresh weight per plant is 138.35 g,with the isothiocyanate content was 621.33 μg·g^-1.The phosphorus concentration screening test showed that 0.4 mmol·L^-1 phosphorus concentration culture was beneficial to the growth of the wasabi plant.Its plant height was 35.42 cm,the fresh weight per plant was 98.26 g,and the isothiocyanate content was 657.77 μg·g^-1.The potassium concentration screening test showed that 3 mmol·L^-1 potassium concentration treatment was beneficial to the growth of wasabi plants,and could significantly increase the underground part biomass and the isothiocyanate content.The plant height was 37.73 cm,the fresh weight per plant was 107.24 g,and the isothiocyanate content was 769.63 μg·g^-1.5.In order to further screen the effects of different combinations of nitrogen,phosphorus,and potassium concentrations on wasabi plant biomass and isothiocyanate content,a three factor and three level orthogonal experiment was designed.The L9（33）results showed tha after 120 days of culture with different concentrations of nitrogen,phosphorus and potassium,the factors affecting the wasabi plant biomass size were nitrogen> potassium > phosphorus,that is to say,the concentration of nitrogen in the nutrient solution has the greatest effect on the biomass accumulation of wasabi plants,followed by the concentration of potassium,and the least effect is the concentration of phosphorus,among them,the concentration of nitrogen and potassium had a significant effect;the main factors affecting the isothiocyanate content of wasabi plants were potassium> phosphorus> nitrogen,and the concentration of potassium had a significant effect.The results showed that the concentration of nitrogen,phosphorus and potassium was 5 mmol·L^-1,0.2 mmol·L^-1 and 3 mmol·L^-1,which were suitable for improving the biomass and isothiocyanate content of hydroponic wasabi.This study established a hydroponic wasabi seed germination system,and selected the best formula and concentration of nutrient solution suitable for the growth of wasabi seedlings,and a combination of nitrogen,phosphorus,and potassium concentrations that was beneficial to increase wasabi plant yield and isothiocyanate content.The hydroponics technology has carried out preliminary tests,which provides a reference for the future industrialization of hydroponic wasabi.