Text by Soham Kacker
Somewhere in the arid scrublands of North India, a babool seed waits in the dried grass. It is March, and the cool temperatures of spring are beginning to rise rapidly, building up into the scorching Indian summer.
If this tiny babool seed were to sprout now, it would likely be burnt to a crisp in days, but it knows better than that. The babool seed, along with thousands of other seed-bearing plants, has evolved one of the greatest superpowers of the plant world: dormancy. This means that even though the seed already contains all the genes needed to make a new babool plant, it can wait until the perfect time to do so.
With the arrival of the monsoon in August, when the seed is exposed to consistent moisture, it suddenly bursts forth with growth. However, the exact cues that tell the seed to begin growing are still shrouded in mystery… some seeds can wait for millennia – the oldest seed to ever germinate successfully was of a tiny white wildflower which had waited in the icy tundra for 32,000 years!
Jamun seeds have a tough coat, and pass undigested through an animal’s stomach. Photo: Dr. Anish Andheria/Sanctuary Photolibrary
The ability to wait, enabled by dormancy, brings many benefits. Plants can programme the germination of their seeds in sync with times when environmental conditions for growth are ideal. This also means that the processes that precede seed-formation, such as flowering and pollination, need not occur in growing seasons, and instead can occur at times when pollinators are most active. For example, Himalayan lilies, which bloom in June and form seeds by November, can wait till the summer of the following year to begin germinating. Seeds also provide plants with an insurance policy in case their populations are threatened. In Uttarakhand, when forest fires burn through the lower levels of pine forests, fire often triggers the germination of dormant seeds buried deeper in the soil – which helps landscapes regenerate after disturbance.
However, this waiting period is also replete with risk. Most seeds are packed full of protein and carbohydrates that are meant to sustain the young seedling after it germinates. This makes them particularly desirable to insects, birds, small mammals, and essentially any creature looking for a hearty meal. To avoid being eaten, many seeds have evolved a stony exterior that protects them from small mammals, and allows seeds to pass unaffected through larger animals. In many cases, this passage through the gut of an animal is what softens the hard seed coat and triggers germination! Other seeds have abandoned dormancy altogether, and evolved to germinate as soon as they ripen, to avoid the vulnerability of waiting. Plants such as coffee and rubber adopt this strategy since they grow in environments where competition and predation risk are very high.
Though evolved to protect the seed, dormancy has proved invaluable to humans. Many of our key crops, including rice, wheat, pulses, beans and oils, come from seeds, and a large reason why it has been possible to domesticate them is because seeds allow for living plant material to be stored over years, and planted as needed. Storing seeds has allowed us to grow a much larger number of plants by virtue of allowing us to rotate what we grow.
Ancient and modern seed banks facilitate the storage of thousands of varieties of plants, both wild and cultivated. In the modern era, these banks form crucial biodiversity safeguards – since they can help prevent the extinction of species or varieties in the wild. Despite global efforts to bank as many seeds as possible, currently only around 10 to 15 per cent of plant species are stored in seed banks.
The patient waiting of seeds has, in many ways, shaped the world as we know it. However, the evocative image of containing all you need for life, and waiting for it to emerge when the time is right, is also a powerful symbol for the human experience. The patient waiting of seeds can teach us that when things seem to be stagnant in life, it may just mean a wait till the conditions are right. And the many ways in which dormancy is finally broken perhaps point us to the many possible paths that lead to growth and success: for some, it may be just a change in weather, for others it may be the stronger heat of fire, and yet others may grow only after being helped by others. But no matter how long you wait or how you eventually grow, seeds show us how that the process can be transformative and nourishing, both for plants and people!
Soham Kacker is a plant ecologist and horticulturist from New Delhi. His research looks at plant conservation and ethnobotanical landscapes in the Indian Himalaya and beyond.
