Neela Kurinji in Western Ghats bloom once in twelve years, why?
C. George Varghese,
Thrissur, Kerala.
Neela Kurinji or Strobilanthes kunthianus is a shrub predominantly found in the Shola forests of Western Ghats and Nilgiri Hills of South India. It flowers once in 12 years and dies immediately after producing seeds. Such plants are called gregarious flowering plants.
Flowering is influenced by the surroundings, temperature, time of exposure to sunlight, humidity and favourable circumstances for pollination, seed formation and seed dispersal .
Under these favourable conditions, the receptors such as phytochromes present in the leaves will send the signals to rush more nutrients, carbohydrates, sugars, water and florigens such as Gibberellins (plant hormones) to the meristems to produce floral buds. These floral buds bloom on receiving more sugars and water. But this blooming will take place only when the inhibitors concentration falls below certain critical levels.
In Kurinji plants this happens regularly after a gap of twelve years. The period between each flowering season is called the Oscillatory period. This is under the control of an endogenous oscillator.
In plants like Neela Kurinji, Bamboo etc, the plants take several years to gather resources and prepare them selves for flowering.
By this time the inhibitor levels in Kurinji must have fallen below the critical levels making it suitable for both flowering and seed formation. Hence mass pollination takes place and seed formation occurs. Once the seeds are shed the plants will die.
Hence it is the inbuilt oscillatory mechanism which is responsible for the mass flowering in Neela Kurinji which in turn is controlled by the inhibitors present in the plant itself.
Interestingly certain Bamboos bloom once in hundred years!
Bengaluru
