Effects Of Spectral Distribution On Growth And Photosynthetic Characteristics Of Rice And Wheat In Artificial Climate Chamber

Rice and wheat are the major grain crops in China,accounting for 55%of the total grain harvest.The level of their yieids determines the food security of China.However,adverse natural conditions will restrict the breeding process and basic research of rice and wheat.Planting rice and wheat in controllable environment is a strategy to deal with adverse climate conditions.Reasonable light environment management,including spectral management of light sources,is the key to indoor rice and wheat planting.The photosynthetic and photochemical conversion ability of leaves and the dry matter transport accumulated during grain filling stage determine the formation of rice yield.Therefore,it has important reference to study the effects of spectral distribution on the growth and development,photo synthetic fluorescence characteristics,material transport and yield of rice and wheat in the controllable environment.Taking ’Huageng No.5’ and ’Yangmai 16’ as test materials,lighting which with composing red lights of 660 nm(R660)and 630 nm(R630)and blue lights of 460 nm(B660)and 440 nm(B440)respectively with a dedicated plant lamp(W)in the whole growth period.The main results are as follows:1.Influence of spectral distribution on growth and development,photosynthetic fluorescence and yield of rice.R660 is conducive to the occurrence of tillers,which ensures the number of ears per unit area and lays a foundation for the formation of rice yield.B460 is beneficial to grain filling,so 1000-grain weight and setting rate of rice are higher than other treatments.Parameters related to light response curve fitting under B460 treatments:maximum net photosynthetic rate(Pmax),intrinsic light energy absorption area,number of light-supplementing pigment molecules,and quantum efficiency of compensation dot were better than other treatments.Chlorophyll fluorescence parameters under blue light treatments:maximum and maximum photochemical efficiency,actual photochemical efficiency,electron transfer efficiency,non-photochemical quenching and photochemical quenching are better than red light;Blue light is beneficial to maintain chlorophyll content and green leaf area in grout stage and delay leaf senescence.Under the blue light treatments,the net photosynthetic rate of the sword leaves remained high,that is,so 460nm was an appropriate light source supplement for rice during the filling period.2.Influence of spectral distribution on morphological characteristics,photosynthetic characteristics and yield of wheatRed light promoted the growth of wheat at the seedling stage,especially the light of R660,with which the plant height was significantly higher than blue light treatments.R660 could increase tillers number while B460 could improve tiller heading rate.The number of green leaves,green leaf area and chlorophyll content were higher under blue light treatments during grouting period,while which decreased with the growth process under the red light.The net photo synthetic rate of flag leaf of wheat decreased little with the growth process under blue light,and according to the correlation analysis,there was no correlation between the net photosynthetic rate of wheat and other photosynthetic parameters,and it was affected by multiple factors.The fitting parameters of the light response curve under blue light treatment were as follows:the absorption area of intrinsic light energy,quantum efficiency of compensation points,and number of pigment molecules for supplementary light were better than that under red light treatment.The 1000-grain weight and setting rate were the highest under B460 treatment.3.Effects of spectral distribution on dry matter accumulation and transportThe previous two chapters pointed out that B460 was beneficial to improve seed setting rate and 1000-grain weight,and the net photosynthetic rate of rice and wheat was higher in grain filling stage,which provided a basis for this chapter.However,whether the accumulation of dry matter before grain filling had an impact on this is worth exploring.The results showed that the ear length under R660 treatment was longer than that under other treatments,which provided evidence for the increase of grain number per ear;B460 was helpful to dry matter accumulation before grain filling stage;higher transportability,output rate and contribution rate of B460 were beneficial to grain filling;B460 and R660 were two high-efficiency spectra,under B460 treatment the 1000-grain weight and seed setting rate were significantly improved during grain filling period,and which also improved under R660 treatment.Whether there exists a "threshold" for dry matter accumulation in leaves and stem sheaths,and even before the "threshold" is reached,leaves and stem sheaths compete for carbohydrates with grains in grain filling stage.