Physiological Study On The Effect Of Spectra On The Yield Of Potato Microtuber

The demand of virus-free seed potato is increasing greatly with the increase of cultivated area,so it is very important to improve the yield and quality of virus-free seed potato.As the original seeds with virus-free,potato mirco-tuberization is a key technology applied in building modern seed industry of virus-free seed potatoes factory production.However,the technology is subjected to the low yield of microtuber.The induction and expansion of microtuber is regulated by light spectra under tissue culture condition.Therefore,physiological study on the effect of spectra on the yield of microtuber are still unclear.The results of this study provided reference for optimizing the light environment of microtuber,provided data and technical support for the research and development and application of light-emitting diode(LED)light source for microtuber.Firstly,this study explored and selecting the appropriate light intensity for the formation of microtuber.Secondly,on the basis of appropriate light intensity,the yield of microtuber,the growth dynamics of organs,the chlorophyll dynamics,the accumulation and distribution dynamics of dry matter,carbon metabolites and the activity dynamics of related enzymes,and hormon were measured and analyzed of potato(cv.Favorita)microtuber under monochromatic light emitted by LED at six wavelengths:440 nm blue light(B440),460 nm blue light(B460),520 nm green light(G520),590 nm yellow light(Y590),620 nm red light(R620),and 660 nm red light(R660)and light spectra emitted by LEDs at six wavelengths:composite light of white light and 440 nm blue light(B440W),composite light of white light and 460 nm blue light(B460W),composite light of white light and 520 nm green light(G520W),composite light of white light and 590 nm yellow light(Y590W),composite light of white light and 620 nm red light(R620W),and composite light of white light and 660 nm red light(R660W).The regulation effect of spectra on the yield of microtuber was investigated.The main results are as follows:1.Effect of light intensity on induction and expension of microtuberThe light intensity of 45-65 ?mol m-2 s-1 could harvest more microtubers and effective microtubers.The light intensity of 65 ?mol m-2 s-1could harvest single microtuber with larger weight.The light intensity of 65 ?mol m-2 s-1 was beneficial to the induction and expansion of microtuber,which was the light intensity suitable for the formation of microtuber.2.Physiological study on the effect of monochromatic spectrum on the yield of micro tuberMicrotubers were induced treated with R620 and G520,and no microtubers treated with other treatments on days 40,indicated that R620 and G520 can make potato plantlet enter the microtuber induction stage quickly.A large number of leaves developed and photosynthate synthesis in the leaves,the chlorophyll content of plantlet,the dry matter accumulation and distribution ratio of microtuber,and microtubers weight under B440 and B460 irradiation were higher than treated by other treatments.The above results showed that blue light was beneficial to the photomorphogenesis and chlorophyll synthesis of leaf,the photosynthate produced by chlorophyll photosynthesis in leaves were the basis for the expansion of microtuber,and blue light was beneficial to the transport of photosynthate to microtuber.Therefore,the microtubers weight were heavier under B440 and B460 irradiation.In addition,the AGPase activity and soluble sugar content of leaves under B460 were higher than under B440,the dry matter accumulation rate of B460 treatment increased faster than that of B440 treatment before the 40th day;the dry matter accumulation rate of B460 treatment was also higher than that of B440 treatment during the 40-8 0d period,the microtubers weight under B460 were heavier than under B440.The above results showed that blue light at 460 nm had a stronger supply capacity of carbon metabolites than blue light at 440 nm,strong carbon metabolite supply capacity was beneficial to increase weight of microtuber,and blue light of 460 nm was conducive to the rapid formation and transport of photosynthate in leaves.Therefore,the microtubers weight was heavier under B460 than under B440.3.Physiological study on the effect of spectral combination on the yield of microtuberMicrotubers were induced treated with other treatments except G520W on days 60,indicated that G520W can not make potato plantlet enter the microtuber induction stage quickly.A large number of leaves developed,the dry matter accumulation and distribution ratio of microtuber,and microtubers weight under B440W and B460W were higher than treated by other treatments,The content of soluble sugar in leaves under B440W and B460W was lower than other treatments.The above results showed that blue and white combine light was beneficial to the photomorphogenesis of leaf,the photosynthate produced by chlorophyll photosynthesis in leaves were the basis for the expansion of microtuber,and blue and white combine light was beneficial to the transport of photosynthate to microtuber.Therefore,the microtubers weight were heavier under B440W and B460W irradiation.In addition,the soluble sugar content of leaves under B440W were higher than under B460W except the 40 d,the dry matter accumulation rate of leaves under B440W treatment decreased faster than under B460W treatment during the 40-60 d period,the dry matter accumulation rate of stems under B440W treatment increased faster than under B460W treatment during the 60-70 d period,the dry matter accumulation rate of stems under B440W treatment decreased faster than under B460W treatment during the 70-80 d period,the microtubers weight under B440W were heavier than under B460W.The above results showed that blue and white combine light at 440 nm had a stronger supply capacity of carbon metabolites than blue and white combine light at 460 nm,strong carbon metabolite supply capacity was beneficial to increase weight of microtuber,and blue and white combine light of 440 nm was conducive to the rapid formation and transport of photosynthate in leaves.Therefore,the microtubers weight was heavier under B440W than under B460W.Above all,65 ?mol m-2 s-1 could promote the expansion of microtuber;620 nm red light advanced the date of microtuber initiation,while the microtubers were rapidly induced later under 520 nm green light.Monochromic blue light can harvest themicrotuber with larger weight and promote the expansion of microtuber.Yellow light was unfavorable to the induction and expansion of microtuber.In view of the results of this study,we can use 620 nm red light to induce microtuber formation quickly,followed by 520 nm green light to increase more microtubers quickly,and finally use 460 nm blue light to ensure the expansion of microtubers in potato agricultural production.Therefore,specific types of light may be used at different growth stages of in vitro potato plantlets to shorten the production cycle and increase the number and weight of valid microtubers.