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Rubber Particle Ontogeny in Taraxacum kok-saghyz

Abdul Ghaffar, Muhammad Akbar Bin
http://rave.ohiolink.edu/etdc/view?acc_num=osu1512031318000982

Abstract Details

2017, Doctor of Philosophy, Ohio State University, Horticulture and Crop Science.
Natural rubber (NR) is a critical and essential raw material in the modern world currently produced by a single tropical tree species, Hevea brasiliensis (para rubber tree). To diversify the genetic base of NR production and provide rubber supply security, other species are now under development. One of these is Taraxacum kok-saghyz (TK), an Astereacean, herbaceous plant native to Central Asia. As TK is still in the early stage of domestication, fundamental knowledge on botany and rubber biosynthesis is useful to guide the crop commercialization process. In my dissertation, I am examining and reporting two areas of rubber production: the origin of rubber particles and the use of environmental and hormonal factors to increase rubber yield. I) The origin of rubber particles Different microscopy methods were used to obtain high image resolution and detailed analysis of early laticifer development and rubber particle ontogeny. The microscopic observations of seedlings showed that rubber particles were produced before laticifers as the laticifers were first observed at the pericycle and outside of the primary phloem group. In mature TK, the highest laticifer numbers were recorded near the plant rosette and the number decreased towards the root tip. A timeline based on laticifer development in seedlings was created and we used the information to understand rubber particle ontogeny. In this study, a rubber particle origin within the secretory pathway of the endoplasmic reticulum-Golgi vesicular complex is visualized for the first time in a rubber-producing species. Unexpectedly, in mature plants, we discovered that the cytoplasmic site of rubber particle development bifurcated to also employ laticifer plastids. The mechanism of rubber accumulation and storage post rubber particle ontogeny was investigated next in both soil- and hydroponically-grown roots. Rubber particles from both cultivation systems occasionally coalesced while still surrounded by cytosol, and likewise after the cytosol had been degraded due to the aging of the laticifer cells. Laticifer cells in hydroponically-grown roots were often univacuolate, and a single, substantial rubber particle was contained within the vacuole. Soil-grown root laticifer cells were multivacuolate and many small rubber particles aggregated to form large rubber masses. II) Environmental factor to increase rubber yield Post-harvest cold treatment increased rubber concentration in some genotypes of TK. However, the effects of cold on rubber biosynthesis in growing plants is unclear. My next study characterized changes in cell structure, rubber particle ontogeny, and rubber yield during cold stress. Outside planting beds and greenhouse hydroponic systems were established. Plants in planting beds (covered and uncovered) were left to experience the winter climate. Cold was applied to roots of hydroponically-grown plants using a chiller. Cold treatment improved rubber yield in both planting systems after 50 days, except in the uncovered beds where rubber biosynthesis was inhibited by freezing soil temperatures and snow. The cold also changed the cell ultrastructure.
Katrina Cornish (Advisor)
145 p.
Agriculture; Biology; Horticulture; Plant Biology; Plant Sciences
Hevea brasiliensis; Taraxacum kok saghyz; natural rubber

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Citations

  • Abdul Ghaffar, M. A. B. (2017). Rubber Particle Ontogeny in Taraxacum kok-saghyz [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1512031318000982

    APA Style (7th edition)

  • Abdul Ghaffar, Muhammad Akbar Bin. Rubber Particle Ontogeny in Taraxacum kok-saghyz. 2017. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1512031318000982.

    MLA Style (8th edition)

  • Abdul Ghaffar, Muhammad Akbar Bin. "Rubber Particle Ontogeny in Taraxacum kok-saghyz." Doctoral dissertation, Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1512031318000982

    Chicago Manual of Style (17th edition)

osu1512031318000982
661
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This open access ETD is published by The Ohio State University and OhioLINK.