The Effect Of Spectral Power Distribution On Growth Of Soybean And Dendrobium Officinale In Vitro

Light is an important factor that influences the growth and development of most plants.Plants recieve the different light signals by light receptors to activate different response and then regulate the process of physiological response,which was presented as morphological change.Nowadays,light spectra have been widely used in the study of photomorphogenesis and the innermechanism in the plant tissue culture.White fluorescent lamp still is the main light source in the plant tissue culture,howerever,its spectral distribution could not meet the demands for plant growth,and it was usually heat and of lower bio-energy efficiency,which lead tothe power waste to a large extent.Light emitting diode?LED?emitted different spectra which could be used to regulate plant photomorphogenesis at a low cost,and LED had a smaller volume,more precise wavelength,lower heat,longer life than white fluorescent lamp.To date,there are many reports on the effects of LED on the growth of tissue culture plantlets,but there are few reports on the effects of light on the whole growth period of planlets in vitro from callus,plant morphogenesis,to reproductive phase,and there are also little reports on the effect of light spectra on in vitro flowering.This paper reviews the research progress in effects of light spectra and PPFD on growth and development of tissue culture plant,light and light receptors,the research progress in soybean and Dendrobium officinale tissue culture technology,the light regulation model and the prospects of LED applicated in plant tissue culture.In this experiment,the effects of different LED emitted spectra on callus differentiation and plant morphogenesis of soybean,in vitro growth and flowering of Dendrobium officinale plantlets was investigated.Main research results were as follows:1.The effect of different light spectra on soybean regeneration in vitro were investgated.The results showed that the 630 nm red light resulted in inhibition of elongation among multiple shoots.Compared with 630 nm red light,660 nm red light promoted remission of this inhibition noticeably,and resulted in greater growth,chorophyll accumulation and dry mass of multiple shoots,and greater growth,dry mass and root development of regenerated plantlet.Green or yellow light added to the complex spectra of red and blue light resulted in inhibition of elongation between multiple shoots,yellow light aggravated this inhibition.Green light added to the complex spectra of red and blue light resulted in greater growth,chorophyll accumulation and dry mass of multiple shoots,and rooting of soybean plantlet in vitro,yellow light improved contents of sucrose and free amino acid.2.The effects of different light intensity on soybean regeneration and growth of soybean rooted plantlet in vitro were investigated.The results showed that average number of shoots per cotyledonary node and induction rate of elongate shoots were highest under RB at 60 ?mol·m^-2·s^-1,and 60 ?mol·m^-2·s^-1 resulted in greater growth,and biomass accumulation of multiple shoots.Greater growth,biomass accumulation,photosynthetic pigment accumulation,root development of regenerated plantlet were under RBG at 60?mol·m^-2·s^-1.Low PPFD presented restriction of multiple shoots and regenerated plantlets.However,the content of soluble protein and car were highest at 70?mol·m^-2·s^-1,and stomatal closure.The results suggested that the PPFD is 60 ?mol·m^-2·s^-1 which could promote the soybean regeneration and growth of soybean rooted plantlet.3.The effects of different light spectra on the growth and flowering of Dendrobium officinale plantlets in vitro were investigated.The results showed that the 630 nm red light resulted in greater plant height and earlier flowering.Compared with 630 nm red light,660 nm red light in the complex spectrum resulted in greater plantlet and flower dry mass,larger stem diameter and peduncles,thicker leaves and petals,a longer blooming period,a greater number of open flowers,higher flowering percentage,increased pollen vigor,and higher carotenoid contents in petals.White light added to the complex spectra of red and blue light resulted in greater plantlet dry mass,larger stem diameter,thicker leaves,AsA and sucrose content of stems.Yellow light promoted carotenoid accumulation in the petals.Red light at 660 nm promoted sugar transport from leaves to stems and stem tips,thereby promoting flowering.These findings will be useful to manipulate the growth and flowering of the ornamental plant,D.officinale.4.The effects of different light intensity on the growth of Dendrobium officinale plantlets in vitro were surveyed.The results showed that stem growth,biomass accumulation,root activity,net photosynthetic rate,sugar and starch content were greatest under 50 ?mol·m^-2·s^-1.Under low PPFD,plant height and leaf area were higher,but stem diameter,leaf thickness and biomass accumulation were lower.Dendrobium officinale plantlets protected themselves with higher leaf thickness,car and soluble protein content,and lower leaf area,chl content and net photosynthetic rate.In conclude,R₆₆₀B was the most suitable light for the inhibition of elongation among multiple shoots from soybean cotyledonary and R₆₆₀BG facilitated the growth of multiple shoots and rooted plantlets in vitro;The complex spectra at 60 ?mol·m^-2·s^-1 was suitable for soybean tissue culture;R₆₆₀BW was most advantageous for vegetative growth and transplant survival of D.officinale,especially promoted quality of stems,R₆₆₀BY was useful for flowering and floral development;The complex spectra at 50 ?mol·m^-2·s^-1 was suitable for D.officinale tissue culture.This study supported the feasibility of application of LED lights be widely used in soybean and Dendrobium officinale plant tissue culture.