Centuries-old ginkgo trees show high activity in genes that fend off disease and produce antioxidants, just as their more youthful counterparts do.
Trees can live for millennia — some ginkgos (Ginkgo biloba), for example, survive more than 1,000 years — but it is unclear how they fend off the ravages of ageing. Richard Dixon at the University of North Texas in Denton, Jinxing Lin at the Beijing Forestry University and their colleagues addressed this question by studying ginkgos ranging from 15 to 667 years old.
The team found that, compared with younger ginkgos, older trees produced less of the plant hormone auxin, which stimulates growth, and more of the hormone abscisic acid, which helps plants to respond to stress. But the old trees photosynthesized with the same efficiency as young trees, and produced seeds that were just as viable.
Gene activity in old trees also resembled that of their younger counterparts: older trees activated genes related to age-related decline, disease resistance, and the production of defensive compounds, such as antioxidants, at the same level as young trees.