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Generation and multiplication of plantlets from callus derived from Haplopappus gracilus (Nutt.) Gray and their karyotype analysisUnopened flower heads of Haplopappus gracilis (2n = 4) provided primary explants for callus production and subsequent induction of organized growth. Callus was initiated from small (3-5 mm in length) floral buds with benzylaminopurine (BAP) (44.4 micromoles; 10 mg/l) and naphthalene acetic acid (NAA) (0.54 micromole; 0.1 mg/l). Lowering the BAP level to 4.44 micromoles (1 mg/l) but maintaining the NAA level, gave rise to organized but highly compressed shoot growing points from an otherwise undifferentiated callus mass. Shoots selected from such cultures were maintainable and could be proliferated by growing 1-1.5-cm stem tip cuttings on Murashige and Skoog basal medium (solidified with agar) containing 0.444 micromole (0.1 mg/l) BAP and 0.054 micromole (0.01 mg/l) NAA. The stem tip multiplication rates obtainable by these means permit reliable strategies for shoot multiplication or production of rooted plantlets. Prolonged subculture and maintenance of shoots on growth regulator-free medium leads to in vitro flowering and greatly reduces rooting capacity. Karyotype analysis of chromosomes from root tip cells at metaphase and chromosome measurements show that karyologically uniform plantlets (based on chromosome number and morphology) can be obtained.
Document ID
20040089975
Document Type
Reprint (Version printed in journal)
Authors
Kann, R. P. (State University of New York at Stony Brook 11794-5215 United States)
O'Connor, S. A.
Levine, H. G.
Krikorian, A. D.
Date Acquired
August 21, 2013
Publication Date
January 1, 1991
Publication Information
Publication: Plant science (Shannon, Ireland)
Volume: 75
ISSN: 0168-9452
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: NSG-7270
CONTRACT_GRANT: NAS1-011395
CONTRACT_GRANT: NSG-1529
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Plant Biology
Non-NASA Center
NASA Program Space Biology
NASA Discipline Number 40-50