Abstract:

[Objective] The orientation and distribution characteristics of the cucumber leaf blade are important structural parameters that determine the light interception and photosynthesis capacity of the canopy. Detailed analysis of leaf azimuth distribution with different cultivation densities will determine the environmental factors that affect leaf distribution and canopy heterogeneity structural characteristics, and support the study of the response mechanism of plant morphology to the environment. [Methods] To study the response of leaf distribution to the light environment under light gradient changes inside the canopy, nine sets of measurement test data under five density treatments were used. A three-dimensional scanning method was used to digitally collect the phenotypic parameters of cucumber canopy organs, and the heterogeneous characteristics of leaf distribution were quantitatively analyzed in different azimuth regions. [Results] Based on the detailed analysis of the relationship between leaf azimuth distribution and solar elevation angle and leaf area index, correlation models were established. The difference in azimuth distribution frequency between the inside and outside of double rows was amended using the cosine function to simulate the response of azimuth distribution frequency to man-made cultivation management. The accuracy of the model was verified by the measured data, and the accuracy rate reached 0.89. [Conclusion] In this study, the response of the azimuthal distribution frequency to canopy growth, light environment and planting management was implemented. It provides an important reference for the acquisition of cucumber canopy phenotypic parameters, and lays the foundation for more accurate cucumber functional and structural plant model construction.

Key words: phenotyping, structure, heterogeneity, canopy, azimuth, cucumber, plant phenomics