Fig. 4From: Adaptive minirhizotron for pepper roots observation and its installation based on root system architecture traitsInstallation patterns of microrhizotrons. a Installation patterns of microrhizotrons. M1, M2, M3 are microrhizotrons in different vertical angles and depth. α is vertical angle, L is lateral roots extension, and R1 and R2 are root length density sampling radius. b, c, and d Roots images from M1, M2 and M3Back to article page