Response and adaptation of Echinochloa crusgalli to photoperiod

To investigate the effects of different photoperiods (8, 10, 12, 14, 16 h·d⁻¹) on the physiological characteristics of Echinochloa crusgalli, we conducted a pot experiment to find the optimal photoperiod by examining the mechanism of photoperiodic regulation on its growth and development. This was undertaken with a view to providing guidance for its scientific introduction and high-yield cultivation. The results showed that 1) the fertility period of E. crusgalli was significantly extended under the photoperiod of 16 h·d⁻¹. 2) The aboveground biomass tended to increase with the prolongation of light duration and the weight of the spikes changed in an “inverted V” shape. 3) With the prolongation of light duration, its antioxidant enzyme activity showed a tendency to decrease and then increase. The chlorophyll content and net photosynthetic rate showed opposite changes. Photosynthetic pigment content showed a tendency to decrease with the advancement in the reproductive period. In summary, the synthesis of photosynthetic pigments of E. crusgalli was promoted under 12 h·d⁻¹ treatment, which enhanced the photosynthetic capacity of leaves and promoted the growth and development of plants. Therefore, E. crusgalli should be introduced and planted in areas with a photoperiod of 12 h·d⁻¹ to increase forage yield to a greater extent in a shorter timescale through appropriate light duration.