The topic for this leaf is “dormancy”, inspired by the many weeks elapsedsince my previous leaf.
Dormancy helps living organismssurvive adverse conditions by reducing their physiological activity, partially(as in hibernating animals) or completely (as in dry seeds). Other plant organsbesides seeds also go dormant, including shoot and flower buds, undergroundbulbs and tubers, etc.
But it is seeds that hold dormancy records. An article linked below tells of date palms grown from 2000years old kernels recovered in archaeological excavations. The kernels were preserved by dry conditions, waiting only for the right conditions to sprout.
Sometimes seeds can be “reconditioned” with treatments that hold off germination but allow pre-germination repair toproceed. My first undergraduate scientific project (under Prof. @Donald Grierson) was on poorly-storedtomato seeds (low viability), reconditioned in osmotic solutions that let themimbibe enough water to start metabolism but not enough to allow germination. Beforetreatment, ribosomal RNA extracted from the seeds was fragmented, indicating acompromised ability to make the enzymes needed for germination. After treatment,the ribosomal RNA was intact, and germination rate was restored to almost 100%.
Given water and suitabletemperatures, one might expect seeds always to germinate, but some wait for anenvironmental trigger. For example, winter cereals planted in late autumn willignore the moist, temperate seasonal conditions, germinating only after exposureto winter chill. Were they to germinate early, the young seedlings wouldsuccumb to frost; ungerminated in the frigid, wet soil, the seeds remainperfectly viable.
In 1928, Russian scientist Trofim Lysenko developed “vernalisation”, artificial chilling to break dormancy in winter wheat. Lysenko promoted theories opposing contemporary genetics, earning himself political favour in Soviet Russia but scientific infamy. Nevertheless, vernalisation is solid science. Furthermore, dormancy seems to be a classic demonstration of Darwinian selection, “survival of the fittest”, with dormancy evolving as a heritable survival trait transmitted in the genes to future generations.
There is a life lessonhere, “Good things come to those who wait”.
Further reading
⏰Wikipedia (2025) “Dormancy” https://t.ly/OJhrA
⏰Scientists in Israel grow date plants from 2,000-year-old seeds | Plants |The Guardian 5-Feb-2020 http://t.ly/lz7Fn
⏰Heydecker W, Higgins J, Gulliver R (1973). Accelerated Germination by Osmotic Seed Treatment. Nature 246, 42–44 https://doi.org/10.1038/246042a0
⏰Wikipedia (2025) Trofim Lysenko, https://t.ly/OpGCp
