| Feasibility study on planting crops in the artificial simulation environment is the frontier of international agricultural science and technology.It is of great importance for the food safety with the increasing of the population,and the development of the vertical agriculture as a substitute.In order to explore the regulation mechanism of crop growth and water use on the coupling effect of light quality and water,the widespread planting of summer maize in North China were the research object.The paper used lysimeters under the rain shelter and pot experiments in growth chambers.The LI-6400 portable photosynthetic analyzer was used to study the change of light qualities on the response to leaf stomatal behavior of maize under drought and full water supply conditions.Different combinations of red and blue light were applied to explore the influence mechanism of maize's eco-physiological characteristics,plant growth,water consumption and water use efficiency under drought and full water supply conditions by light quality.This study provided theoretical basis for optimal control of crop growth and water consumption under the future of artificial light environment.The main results were as follows:(1)The leaf exchanges of summer maize were analyzed in lysimeters under the rain shelter to reveal the transient response of mazie leaves stomatal conductance(Gs),photosynthetic rate(Pn)and transpiration rate(Tr)to the red and blue light ratio under different water conditions.Under the full irrigation(W)and no irrigation(D)conditions,red to blue ratio was set at 0,25%,50%,75%and 100%,during the three main growth periods(jointing stage,heading stage and filling stage)of summer maize(Zheng Dan 958).The results showed that the mean values of Gs,Pn and Tr in leaves were significantly higher compared with no-irrigation at the tasselling stages.The differences between these two treatments were not significant at the jointing and filling stage.Under these two water treatments,the Gs,Pn and Tr were maximum under the pure red light and decreased with the increase of blue light proportion.Photosynthetic rate(Pn)was negatively correlated with total radiation(Q)(P<0.05)significantly during three main growth stages.(2)In the potted maize experiment at the constant temperature and humidity in growth chambers,2water treatment(W,D)and 5 red to blue ratios(R,R/B=3,1,1/3 and B)were set.The results showed that,under both two water treatments,the maximum Pn of maize leaf was at R/B=1,the maximum plant height was at R,which showed an upward trend with the increase of R/B ratio roughly;the maximum dry weight was at R/B=1,followed at R/B=3,red and blue>R>B;biomass water use efficiency(WUE_b)at R/B=3,1 and R was significantly higher than other two treatments.For the watered treatment(W),the change trend of Gs and Tr were R/B>B>R;the maximum content of chlorophyll and leaf area were at R/B=1,and the maximum root shoot was at R/B=3;water consumption during the whole observation period increased with the proportion of blue light.For the water stressed treatment(D),Gs,Tr,chlorophyll content,leaf area was maximum at R/B=1,followed at R/B=3;the maximum root shoot ratio was at R/B=3,followed by R/B=1,water consumption of R/B=1,1/3 treatments were higher.But harvest index changed with compound light>R>B;as a result,high red light ratio(R/B=3,1)treatments were beneficial to the plant growth,accumulation of biomass and improvement of water use efficiency of maize.(3)On the basis of selecting the best ratio interval of red to blue light,the temperature,humidity and water conditions were controlled at consistent,and irrigation levels(W,D)and ratios of red to blue(CK,R/B=1,4,8,12 and 16)were set.It showed different ratios of red to blue light effect on maize's eco-physiological characteristics,plant growth,water consumption and water use efficiency under a weak blue environment.The independent effect of water and R/B on water consumption,biomass,water use efficiency for biomass yield of maize was significant(P<0.01),the coupling effect of water and R/B on water consumption,biomass,water use efficiency for biomass yield of maize was also significant(P<0.05).The maximum daily water consumption(ET)of maize were at R/B=12 so the total amount of water consumption was largest.Under two water treatments,the best red and blue ratio was at R/B=16,because the leaves had not only higher photosynthetic rate but also relatively high water use efficiency.WUE_b was positive-linearly correlated with biomass and also related to water consumption in parabolic curve. |
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