重庆是全国唯一的柑橘黄龙病非疫区及首创“柑橘良种无病毒三级繁育体系”的产区。 但是, 由于重庆年均日照时数少且年内分配不均, 使其柑橘育苗周期显著长于其他产区, 严重制约了重庆柑橘苗木产业的发展速度。 利用新型节能光源发光二极管（LED）进行秋冬季补光, 可缩短柑橘育苗周期, 加快优质无毒柑橘新品苗木的繁育。 为了阐明不同LED光质及配比对枳壳幼苗生长发育的影响, 以砂培枳壳幼苗为试验材料, 采用6种LED光处理(红光、 蓝光、 红蓝1∶1、 红蓝4∶1、 红黄蓝4∶1∶1 和白光), 统计、 测定了植株的表型和生物量指标, 为缩短柑橘砧木及新品种苗木繁育周期提供理论和实验依据。 结果表明: 与荧光灯相比较, 不同的LED复合光均显著促进了根伸长、 茎增粗（除红蓝1∶1外）、 叶变窄; LED红蓝1∶1和红蓝4∶1复合光抑制茎伸长、 叶片数形成, 促进叶增厚, 且后者的叶长被促进、 叶面积增大; 而红黄蓝4∶1∶1复合光促进茎伸长、 叶形成、 叶伸长、 叶变薄和叶面积增大。 相对于单色光来说LED白光及高比例红光的复合光更有利于枳壳幼苗物质合成以及其地上、 地下物质分配量; 且LED红黄蓝4∶1∶1复合光下枳壳幼苗地上部分的生物量最大, 而根冠比最小。 因此, LED红黄蓝4∶1∶1复合光最适宜于枳壳幼苗的物质合成与地上部分生长, 可为光照不足季节或地区（特别是重庆地区）柑橘苗木的LED精准补光技术构建提供理论依据。

Chongqing, the only non-endemic area of Huanglong disease, has been established firstly virus-free three-stage breeding system for quality Citrus variety in China. However, that the annual sunshine hours in Chongqing are few and unevenly distributed during the year prolongs the growth period in Citrus seedlings compared to other’s Citrus plantation areas. Therefore, this seriously restricts the developing speed of citrus nursery industry in Chongqing. Recently, the light emitting diode (LED) has been used as supplementary lighting to cultivate Citrus during the autumn and winter that can shorten the growth period of citrus seedling and accelerate the virus-free breeding of new variety. In order to investigate the effects of different LED light qualities on their seedlings growth, trifoliate orange (Poncirus trifoliata L. Raf) in sand culture were selected as materials. 2-month-old seedlings were exposed to 150 μmol·m-2·s-1 irradiance for a 16 h·d-1 photoperiod under white fluorescent lamp (FL) and the following six LED light, respectively: red light (R), blue light(B), 1∶1 ratio of red/blue (RB 1∶1), 4∶1 ratio of red/blue (RB 4∶1), 4∶1∶1 ratio of red/yellow/blue (RYB 4∶1∶1), white light (W). Their phenotypic and biomass indices were measured. Results showed that roots of seedlings were significantly longer, stem diameters (excluding RB 1∶1) were wider and leaves were narrower under composite LED light treatments than those under fluorescent lamp treatement. Compared with fluorescent lamp treatment, stem elongation were inhibited, along with decrease in leaf numbers and increase leaf thickness under RB 1∶1 and RB 4∶1 treatments, under which leaf length and area were increased. Furthermore, stem elongation, leaf number and leaf length increased, while leaf area enlarged, and leaf thickness decreased under RYB 4∶1∶1 treatment in comparison with fluorescent lamp treatment. Dry matter accumulation and biomass distribution of shoot and root were better under white LED light and high ratio red LED light treatments than those under monochromatic light treatments, particularly with the greatest shoot biomass and the minimum root/shoot ratio under RYB 4∶1∶1 treatment. So, it is concluded that RYB 4∶1∶1 treatment is the best choice for the matter accumulation and shoot growth of trifoliate orange seedlings. This can offer the theoretical evidence for the accurate supplemental lighting system on the season or area of lack light, especially in Chongqing.