Soil-filled rootbox minirhizotron system: a non-destructive and real time observation of root penetration in soil hardpan in rice

Root plays important roles by exhibiting adapted response specific to various soil moisture stress conditions. One of the adaptive responses of plants to drought is the development of deep, thick and extensive root systems, which attributed to the increased in water and nutrient extraction in the soil. Deep root measurements are based on conventional method of destructive sampling thus, these studies have been facing difficult problems in measurement, owing to the lack of an appropriate method. Recent trend in mini-rhizotron technique have received increasing interest and attention in the field or root research by collecting digital images that allows the development of individual roots to be observed in time and space. In this paper, a modified method of real time and non-destructive of measuring penetrated roots in the soil hardpan using the combination of soil-filled rootbox and mini-rhizotron systems. The basic components and process of assembling the modified pinboard rootbox with mini-rhizotron system, and the subsequent data analyses using the WinRhizo software has been briefly discussed. Recent developed and modified pinboard rootbox (340 mm x 100 mm x 650 mm) with mini-rhizotron system demonstrated continuous observation and tracked the development of the penetrated roots or specific root segments in the soil hardpan using high-resolution camera. The main advantage of modified rootbox with mini-rhizotron system is that repeated root images can be recorded for extended period of time periods and also specific root segment can be tracked in time by high-resolution camera. Further, this method enables us to collect the whole root system with minimum impairment or disturbance to its structure. On the other hand, this modified technique can also be used to evaluate the response of root system development and plant water use precisely under regulated target soil moisture conditions.