灰色关联分析法对叶用莴苣生长期光环境的优化

Optimization of the Light Environment of Lettuce in Growth Period Based on Gray Relational Analysis

为保证设施叶用莴苣周年生产的供给,研究了人工气候条件下不同光照模式对叶用莴苣生长期生长特性的影响,以确定叶用莴苣生长的最优光环境,实验以‘意大利’全年耐抽薹叶用莴苣(Lactuca sativa L.)为试材,设计LED红蓝配比(7:3、5:5、3:7)、光周期(12L/12D、16L/8D、20L/4D)及光照强度[100μmol/(m^2·s)、150μmol/(m^2·s)、200μmol/(m^2·s)]的3因素3水平正交实验,利用灰色关联分析法分析不同光照模式对生长期叶用莴苣植株的生长、光合色素含量及营养品质的影响。结果表明,不同处理对叶用莴苣生长期生长及品质的影响不同。相比于其他光环境条件,处理9[红蓝配比3:7,光周期20L/4D,光强150μmol/(m^2·s)]更有利于光合色素的积累。红蓝配比3:7的光照模式较其他处理更有利于蛋白质合成;处理3[红蓝配比7:3,光周期20L/4D,光强200μmol/(m^2·s)]有利于降低生长期叶用莴苣叶片硝态氮含量,促进可溶性糖的积累。综合分析得出3个光照因子对水培叶用莴苣生长及品质影响的重要程度依次为:光强、光质配比、光周期,最适的光照模式组合为:红蓝配比7:3、光强200μmol/(m^2·s)、光周期20L/4D。本研究结果可为叶用莴苣生长的最适光环境提供参考,同时为LED灯具在植物照明领域的设计提供技术支持。

In order to ensure the annual supply of facility lettuce, the effects of different lighting modes on the growth characteristics of lettuce in growth period under artificial climatic conditions were studied to determine the most suitable light environment for lettuce growth. The cultivar of lettuce（Lactuca sativa L.） used in this experiment was ＂Italy＂, which has the advantage of resisting bolt all year round. We designed the orthogonal test with the ratios of red to blue light 7：3, 5：5 and 3：7, respectively, photoperiod 12 L/12 D, 16 L/8 D and 20 L/4 D, respectively（L for light, and D for Dark）, and light intensity 100 μmol/（m^2·s）, 150 μmol/（m^2·s） and 200 μmol/（m^2·s）, respectively. The influence of the light settings on the growth, photosynthetic pigment content and quality of lettuce in growth period was analyzed using the gray relational analysis method. Results showed that compared with the other light environmental conditions, treatment with the ratio of red to blue 7：3, photoperiod 20 L/4 D and light intensity 150 μmol/（m^2·s） was more conducive to the accumulation of photosynthetic pigments. The combination with the ratio of red to blue 3：7 was more conducive to protein synthesis than other treatments. Treatment with the ratio of red to blue 7：3, photoperiod 20 L/4 D and light intensity 200 μmol/（m^2·s） had lower nitrate content and higher soluble sugar than other light treatments. From the results obtained in this paper we could conclude that the most influential factor on the growth and chemical accumulation of lettuce in the growth period was light intensity, followed by light quality and the least was photoperiod. The most suitable combination of light was as follows： the ratio of red to blue 7：3, light intensity 200 μmol/（m^2·s）, and photoperiod 20 L/4 D. These results would provide some references for the settings of the best light environment for lettuce and some technological support for the design of LED（Light-emitting diode） lamps in the field of plant-lightings.