LIZhixin, WANGLong, LIXin, TANNengzhi, CHENJingliang, CHENYujia, YANGYanjie, YANZhengnan, ZHANGYuhan
In order to solve the negative influence of weak light in solar greenhouse on the yield and quality of strawberry in winter and spring in northern China, the supplementary light was set inside the greenhouse [supplementary light intensity was (20±3) μmol/(m2·s), supplementary light duration was 3 h/d, T1] for strawberries, and no supplementary light treatment was set as control (CK). The results showed that the supplementary light treatment significantly promoted the increase of plant height and photosynthetic pigment content in strawberry leaves, and the chlorophyll a content, chlorophyll b content, total chlorophyll content, and carotenoid content in strawberry leaves increased by 27.3%, 35.9%, 21.7%, and 19.4%, respectively. Absorption flux per reaction center (ABS/RC), trapped energy flux per RC (TR0/RC) and dissipation energy flux per RC (DI0/RC) decreased by 13.5%, 7.6%, and 20.0%, respectively, which indicated that the pigment unit of strawberry leaf antenna absorbed and captured less light energy, resulting in less light energy for electron transport. Compared with strawberry plants grown without supplementary light, the energy loss of photochemical reaction in strawberry leaves was significantly reduced by supplementary light. The contents of soluble protein, soluble sugar, and vitamin C in strawberry fruit treated with supplementary light increased by 56.1%, 6.8%, and 3.1%, respectively, compared with those treated without supplementary light. In terms of the influences of volatile substances, the nitrogen oxides, alkanes, sulphide, alcohols and aromatic compounds, alkanes and aliphatic groups increased by 15.3%, 16.2%, 10.6%, 6.8%, and 6.7%, respectively, compared with the no supplementary light treatment. In conclusion, solar greenhouse supplementary light treatment significantly promoted the growth of strawberry plants, the improvement of strawberry fruit quality and the accumulation of flavor substances.