Hope to revive lost varieties of trees from their broken seeds

 Hope to revive lost varieties of trees from their broken seeds 

By: Dipankar Chakraborty

After detailed experiments with the unique seed germination pattern of Garcinia gummi-gutta or kokum fruit-bearing tree, found in abundance in the Uttara Kannada parts of Western Ghats jungles, scientists have formulated a 'model-system' that can be used to protect the tree against vagaries of nature and ensure its survival in the difficult forest ecology.
The model system is also expected to open up fresh lines of investigations into seed biology and evolutionary ecology.
During their extensive research scientists Dr Geeta Joshi, Dr Arun Kumar and Dr Y B Srinivasa of Institute of Wood Science and Technology (IWST) and Dr Balakrishna Gowda in the Department of Forestry and Environment Science at the University of Agricultural Sciences, GKVK, found that even the fragamented seeds of the rinds of the pulpy fruit of Garcinia gummi-gutta have the capacity to germinate and develop complete seedlings.
The conclusive evidence about the fragmented kokum seeds' regenerative capacity came to fore after scientists found that seeds damaged by fruit-eating animals germinated faster than the ones left intact. In the tropical evergreen forests of the Western Ghats, the period from June to August is the fruiting season. The season coincides with the peak of southwesterly monsoon, a good time for all the seeds in the jungle soil to germinate but for the Garcinia gummi-gutta seeds.
The hard coat of Garcinia gummi-gutta seeds prevented them from germinating during the rainy season. By the time the primary root could emerge out of the seed and the first seedling appear the rains would have been long over and a long spell of harsh summer months begins. The seeds of the majority of the trees species germinate coinciding with the monsoon. Their seedlings also take firm roots ahead of the summer months. This ensures a better chance of their survival in the competitive forest environs.
Scientists, however, have observed that Garcinia gummi-gutta seeds damaged by fruit-eating mammals in the forest while feeding on them germinate much before the onset of the long summer and hence stand a far better chance of survival. This is not the case with the fully coated seeds of the tree.
Speaking about their experiments with the germination process of the kokum fruit seeds, the scientists told the Bangalore Mirror: "A study was carried out to observe the effect of seed coat on germination by sowing seeds with and without seed coat separately in a sand bed and watered twice a day. Seeds with their seed coats intact took about four months to initiate germination. In case of seeds without the coat, the germination started by three weeks." What further surprised scientists was the fact that not only the seeds with broken coat germinated faster but also the seeds fragmented during animal feeding were capable of developing independent seedlings.
Speaking about their research into the germination of the fragmented seeds of kokum fruits of G. gummi-gutta tree, the four scientists observed: "We have shown that seed fragments not only produce root and shoot but also have enough reserve material to support the development of complete seedlings. Therefore, germination of seed fragments may have evolved as a unique way of exploiting mammalian frugivory (fruit-eating habit) for seed dispersal." This very fact has now prompted scientists to examine whether seed-dispersing during animal feeding of fruits and germination of fragmented seeds could be used as 'model system' for fresh lines of investigations into various other branches of science such as morphogenesis (the biological process that causes an organism to develop its shape), physiology (biology dealing with normal functions of a living organism and their parts), seed biology and evolutionary ecology (the science of how interactions between and within species evolved).


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