Journal of the Rubber Research Institute of Sri Lanka

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Author: search.filters.author.Seneviratne, P.Subject: search.filters.subject.Hevea brasiliensis

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    The effects of the basic medium and the carbohydrate content on shoot cultures of Hevea brasiliensis
    (Rubber Research Institute. Agalawatte, 1996) Seneviratne, P.; Flegmann, A.W.; Wijesekera, G.A.S.
    Woody Plants Medium (WPM) was superior to murashige and skoog medium (M S), which showed better axillary bud growth of both juvenile and mature shoot materials. The effect was more pronounced in later passages, in particular, on the survival rate of the cultures. Most of the cultures grown on M S medium did not survive more than 24-28 weeks, while on WPM medium cultures survived for more than one and a half years, until the experiment was terminated. The level of sucrose in the medium also had an effect on the growth of the primary axillary shoots, specially the length and the leaf growth. The length of primary axillary shoots incresed with the increasing levels of sucrose in the medium up to 10 per cent with clonal materials. Explants did not survive beyond 8 weeks when the medium was not supplied with sucrose.
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    Comparison of yields between budgrafts and mother trees in Hevea brasiliensis Muell. Arg.
    (Rubber Research Institute . Agalawatta, 2007) Pathiratna, L.S.S.; Wijesuriya, W.; Seneviratne, P.
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    The correlation between branching and the tree growth of Hevea brasiliensis (Muell.Arg.)
    (Rubber Research Institute of Sri Lanka. Agalawatte, 1996) Seneviratne, P.; Nugawela, A.; Ramawickrama, D.
    The main objective of the present study was to see whether there is a correlation between the number of branches and the tree grwoth in hevea brasiliensis. Considerable variation in brancing habits is observed among the trees of different clones. Also, some clones such as RRIC 121 show less brancing when compared to other clones such as RRIC 100 indicating brancing is also a clonal characteristic. Canopy architecture too, shows differences among trees within a clone. Highly significant positive correlation was observed between the number of branches and the tree girth for all clones tested for trees aged from one year to seven years. The correlation between the canopy distribution (grouped as very good, good or poor) and the tree girth was also positive.
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    The growth, phase change and rejuvenation of trees with special reference to Hevea brasiliensis (Muell.Arg.)
    (Rubber Research Institute. Agalawatte, 1996) Seneviratne, P.
    The growth of seedlings and buddlings of rubber is periodic and the growth during the first 3-5 years is purely vegetative and the trees grow upward without brancing. Also rubber tree undergoes the phase change during its development process. Trees attain the mature phase in 5-6 years of age which is generally characteristic by flowering and wintering. As for as the rubber industry is concerned, the physiological and biochemical characteristics related to the mature phase, such as slow growth rate, losing of root regeneration capacity, high content of phenolic compounds etc. are all undisarable. All improved clonal materials belong in this phase.