非连续光对无土栽培番茄苗期无机元素吸收的影响

本研究在人工光型植物工厂中采用岩棉种植番茄植株，分析了在总光量一致的基础上红光背景下蓝光补充介入和蓝光取代介入两种非连续供光模式对番茄植株营养液无机元素吸收及叶片色素光谱参量的影响。结果表明，与连续红光相比，蓝光以不同方式介入均降低了番茄叶片中K元素含量而提高了茎中K元素含量，蓝光介入一定程度上抑制了番茄K元素由茎向叶片的运输；蓝光以不同方式介入均提高了番茄地上部中Mg含量（增幅8.93%~13.63%），而降低了地上部Fe含量（降幅28%~48%）及Mn含量（降幅3.93%~21.24%）。其中蓝光补充介入模式下番茄叶片中Mg元素含量随着蓝光补充强度的升高而增加，叶片Mg含量在蓝光取代介入模式下高于蓝光补充介入模式而地上部Fe含量趋势则相反，蓝光取代介入的非连续光模式较蓝光补充介入模式而言更有利于刺激叶片中Mg的积累而抑制地上部Fe的积累。与连续红光相比，蓝光以不同方式介入后番茄叶片色素光谱参量Hue值（色相角）和MCARI值（修正叶绿素吸收比指数）均有所提高，相反，Red/Green值（红绿区域光谱反射比）均有所降低，蓝光补充介入模式下叶片Hue值和MCARI值随蓝光补充强度的升高而增大，R/RB80处理下Hue、MCARI值最高，较对照分别提高4%、124%；蓝光取代模式下Hue值和MCARI值随蓝光间歇时间的延长先增大后减小，R/RB(1h)处理下Hue、MCARI值最高，较对照分别提高6%、215%。番茄叶片在绿光波段的反射率与各处理下Hue、MCARI值变化趋势接近，而番茄叶片中Mg元素含量与叶绿素光谱参量呈正相关性。蓝光取代介入的非连续光模式较蓝光补充介入模式而言更有利于刺激叶片类胡萝卜素分解和叶绿素积累，非连续供光模式通过调控番茄植株无机元素的吸收进而作用于叶片色素的形成。本研究为无土栽培番茄光环境调控提供了理论依据。

Effect of Discontinuous Light on Absorption of Inorganic Elements in Soilless Tomato Seedlings

Tomato plants were planted in rock wool in an artificial light plant factory and exposed to red background light with supplementary or substituted blue light. The nutrient element absorption by tomato plants and the spectral parameters of tomato leaves were analyzed. The results showed that compared with constant pure red light, both supplementary and substituted blue light decreased the content of K in tomato leaves but increased that in tomato stems, interventional blue light might inhibit the transport of K from stems to leaves;both supplementary and substituted blue light increased the content of Mg in the whole tomato plant by 8.93%~13.63% while decreased that of Fe by 28%~48% and Mn by 3.93%~21.24%. Among which, Mg content in tomato leaves was increased with the increase of supplemental blue light intensity. The content of Mg was higher in tomato plants treated with substituted blue light than that treated with supplementary blue light, while Fe content showed opposite trend. Substituted blue light seemed more conducive to the accumulation of Mg in tomato leaves as well as the inhibition of Fe in the whole plant. Compared with pure red light, the Hue and MCARI value of tomato leaves treated with interventional blue light was increased, while the Red/Green value was decreased;Hue and MCARI value was increased with the increase of supplemental blue light intensity. Hue and MCARI value were the highest under R/RB80 treatment, which were respectively 4% and 124% higher than the control. In substituted blue light mode, Hue and MCARI value first increased and then decreased with the prolongation of blue light intermittent time, reaching the highest values under R/RB(1h) treatment, which were 6% and 215% higher than the control respectively. The reflectance of tomato leaves in the green light area was close to the change trend of Hue and MCARI value among treatments, while Mg content in tomato leaves showed a certain positive correlation with chlorophyll spectral parameters. Comparing with the spectral parameters of tomato leaves under the two modes of interventional blue light, it can be seen that substituted blue light was more conducive for the decomposition of carotenoid and the accumulation of chlorophyll in leaves than supplemental blue light on the basis of equal total light amount. The discontinuous light supply mode might regulate the absorption of inorganic elements in tomato plants, thereby affecting the formation of leaf pigments. The research result can provide some theoretical basis for the regulation of light environment in soilless tomato cultivation.