Unmixed images of young and old secondary phloem in longitudinalsections from grown current-year stems. a–d Order fromyoungest to oldest phloem. The synthesized trans-polyisoprene firstaccumulated as granules (a–c) and then formed a fibrous structure(d). La laticifer, Ra ray, Cc companion cell, St sieve tube, Pc parenchymacell. Scale bars are 10 μm. Trans-polyisoprene is displayedin yellow, lipid-soluble substances in magenta, and cell walls in cyan