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Kangsheng Yao

Document Type

Dissertation - University Access Only

Award Date


Degree Name

Doctor of Philosophy (PhD)

Department / School

Plant Science

First Advisor

C.H. Chen

Second Advisor

C.R. McMullen


The objectives of this research were to investigate the differentiation patterns in cultured inflorescences of big bluestem (Andropogon gerardii Vitman.), intermediate wheatgrass (Agropyron intermedium (Host) Beauv.) and European sloughgrass (Beckmannia eruciformis (L.) Host), and in cultured anthers of big bluestem and intermediate wheatgrass in conjunction [sic] with plant regeneration. Young, unemerged inflorescence cultures grown on RM medium plus 5 mg/L 2,4-D initiated morphogenic calli. Calli subcultured on the high 2,4-D medium could occasionally differentiate into shoot primordia, but plant regeneration did not occur until 2,4-D was withdrawn or drastically reduced. BAP at 0.1 or 1 mg/L in RM medium enhanced shoot differentiation in the calli of all three grasses studied. Histological samples, taken from various stages of culture grown on the differentiation media with or without BAP supplements, revealed that only monopolar pattern of differentiation existed in the big bluestem calli. In intermediate wheatgrass and sloughgrass callus cultures, both embryogenesis and organogenesis were observed. In addition, plant regeneration also occurred in primary cultures of sloughgrass and intermediate wheatgrass, apparently by morphogenetic shift in the extremely young floral primordia of the explanted inflorescence segments. Androgenesis in big bluestem and intermediate wheatgrass anthers started with symmetrical divisions of pollen nuclei immediately followed by cytokinesis, or alternatively, by the formation of multinucleate pollen grains, which were later partitioned by repeated cytoplasmic divisions. A total of 53 plantlets were regenerated from 9480 intermediate wheatgrass anthers cultured on N6, Tsay's, Yu-pei and 85D12 media plus 9% sucrose, various concentrations of kinetin and 2, 4-D or NAA. Among these, 45 were differentiated in calli through embryogenesis while the other 8 plants appeared to evolve directly from microspores. However, all of the plantlets were albino. Initiation of sporophytic growth was observed in big bluestem anthers during the first three weeks after explanted on N6 or Yu-pei medium plus 1 or 2 mg/L 2,4-D and 60 to 120 g/L sucrose, but plant regeneration was not achieved.

Library of Congress Subject Headings

Grasses -- Genetic engineering
Grasses -- Micropropagation
Forage plants -- Varieties




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