Browsing by Author "Tregear, J."

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    Cryopreservation as a Tool for the Management of Coconut Germplasm
    (2011) Malaurie, B.; N'Nan, O.; Bandupriya, H.D.D.; Borges, M.; Verdeil, J.L.; Tregear, J.
    We present hereafter a review of different collaborative research studies carried out on the cycopreserntion of coconut plumules excised from the zygotic embryo. Plumule (shoot apical meristem and leaf primordia) tissues have shown different degrees of success in cropresen ation depending on th combination of alginate encapsulation and osmotic or evaporative dehydration used. The percentage of regrowth was progressi\\ Cly impro\\ ed from vitrification (0%), to osmoprotection (10%), and subsequently the encapsulation-dehydration technique allowed 20% regrowth level into leafy shoots. Addition of abscisic acid (20 to 40 JI:\\I) boosted recovery growth after freezing (up ta 40%). Histological studies have clearly shown that the addition of lower amounts of ABA (10 JIM) allows cells to maintair. the structural characteristics of control cells for immersion into liquid nitrogen without dehydration. The effect of plant material conditioning, for transport from collecting site to laboratories, was studied to identify possible effects of unc( ntrolled factors on tissue tolerance to cryopreservation. Three conditioning methods lemb o set in endosperm core (ALB); emb,·yo transferred onto of solidified agar (5W); emb, o immersed into KCI solution (KCI)I were u~ed. 5W performance is clearl~ more efficient when combined with dehydration and freezing. giving 40% recovc . These results are interesting as they show that the medium surrounding the ~mb 1 (endosperm or medium supply) can be replaced by agar alone. without nutritive factors. This approach should also facilitate germrlasm exchanf e. As a result of the absence of phloem vascular bundles in the plumular tissues, the approach described here should increase the scope for obtai.ling material free of pathogenic agents, an essential prerequisite for the conserntion and exchange of germ plasm. This approach should be a strong point in the fight lIgainst Lethal Yellowing Disease. the most serious disease affecting coconut plantations.