https://phys.org/news/2018-05-troika-proteins-leaf-age-onset.html

Among all the molecules that take part in the aging process, one of the largest and most important protein groups is called NAC. Technically known as transcription factors, NAC proteins are able to finely regulate the expression of other NACs and other age-related proteins. IBS researchers have identified which NAC proteins are the most influential at different stages of plant aging.

The research team used Arabidopsis thaliana plants, each lacking one of 49 selected NAC proteins, and measured the effects on other NACs. Depending on which NAC protein was missing, other NACs may be more or less expressed in the leaves of 14, 18, 22 and 26-day- old plants. Arabidopsis has a rapid life cycle of about 6-8 weeks from germination to seed production: it is mature at day 14, and displays more than 40% chlorophyll loss at day 26. Compared to a person, the plant would be similar to a 30-year-old at day 14, and starting to save for retirement at day 26.