Abstract Detail

Development and Structure

Abdul Ghaffar, Muhammad Akbar [1], Meulia, Tea [2], Cornish, Katrina [1].

Histological Study of Laticifer and Rubber Particle Ontogeny in Taraxacum kok-saghyz Roots.

Taraxacum kok-saghyz (TK) is being developed as a commercial crop in the US and Europe as an alternative to Hevea brasiliensis, the tree that produces industrial rubber. Both Hevea and TK contain pipe-like multi-nucleate vessels called laticifers which produce latex. As a potential new rubber crop, understanding laticifer origin and rubber particle ontogeny in TK will be useful in manipulating rubber production and yield. Thus, the objectives of this study are to gain a histological understanding of TK laticifer development and the ontogeny of rubber particles by characterizing the morphology and development of rubber-producing cells at both the seedling stage and in mature TK plants. Different microscopy methods were used to obtain high image resolution, and detailed analysis of early laticifer development and rubber particle ontogeny. The microscopic observations on the seedlings showed that rubber particles were produced before laticifers, as early as eight days after germination, beginning at the cotyledonary collar areas. Laticifers were first observed 14 days after germination in the cotyledonary collar area at the pericycle and outside of the primary phloem group. In mature TK, high laticifer numbers were recorded near the plant crown and the numbers decreased toward the root tip. Conversely, the laticifer density was highest when the root diameter was small. The rubber particles, which are spherical or ovoid, were not as easily identified in seedlings as they were in mature TK plants. However, these particles began to appear 10 days after germination. The mature plants exhibited similar rubber particle morphology to H. brasiliensis and Parthenium argentatum (guayule). In addition, laticifer plastids, membranous organelles found in the cytoplasm of laticifer cells, produced some of the rubber particles while other rubber particles were formed independent of this plastid. Also, two distinct rubber particle morphologies are found in TK. Rubber particles developed in the cytoplasm (plastidic rubber) are irregularly shaped prior to moving inside the vacuole. Once in the vacuole, the outer layer of the rubber particle becomes smooth (vesicular rubber). In conclusion, these findings have provided us with useful information on laticifer and rubber particle ontogeny that we can use further in studying and explaining the de novo site of rubber particles as well as to predict rubber production in TK roots.

1 - The Ohio State University, Department of Horticulture and Crop Science, Williams Hall,1680 Madison Ave., Wooster, OH, 44691, USA
2 - The Ohio State University, Molecular and Cellular Imaging Center, Selby Hall,1680 Madison Ave., Wooster, OH, 44691, USA

Keywords:
Taraxacum kok-saghyz
 Laticifer
Rubber Particle Ontogeny.

Presentation Type: Oral Paper
Session: 29, Development and Structure I
Location: 202/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 4:15 PM
Number: 29011
Abstract ID:312
Candidate for Awards:Katherine Esau Award,Maynard F. Moseley Award