Figure 4 Principal component analysis of metabolomics profile of control and biuret-treated rice suspension cells. Rice cells were transferred into a medium without biuret or with 0.3 mmol L-1 biuret and harvested 3 and 5 days after transfer. Closed symbols indicate control cells, and open symbols indicate biuret-treated cells. Circles indicate day 3 samples, and triangles indicate day 5 samples.