Root cultures, maintenance

The adventitious root cultures of Datura innoxia, Duboisia hybrid M-II-8-14 (a cross-bred between D. myoporoides and D. leichhardtii), and Scopolia tangutica were established from the axenic shoot cultures or intact plants (in the case of Duboisia) on MS solid medium containing 0.1 mg/1 NAA or 1.0 mg/1 lAA. The adventitious roots were maintained in MS liquid medium containing the same phytohormones (0.1 mg/1 NAA or 0.5 mg/1 lAA) in the dark. Addition of auxin in the culture medium has been employed for the maintenance of adventitious root cultures [14], however, the adventitious roots of H. albus and H. niger were induced and maintained in hormone-free 1/2 MS medium [15]. 

Pitta-Alvarez, S. A. and Giulietti, A. M. (1995) Advantage and limitations in the use of hairy roots cultures for the production of tropane alkaloids use of anti-auxins in the maintenance of normal root morphology. In Vitro Cell. Dev. Biol. Plant. 31,215-220. 

An average 60-day-old tobacco plant contains about 250 mg of nicotine. Based on the net carbon dioxide fixation and the rate of turnover of nicotine in the plant, maintenance of this amount of nicotine may represent as much as 10% of the plant s total metabolism (Robinson, 1974). The half-life of nicotine in tobacco plants is about 22 h (Waller and No-wacki, 1978). The alkaloid content of plants of Nicotiana sylvestris undergoes a fourfold increase following damage to the leaves (Hartmann, 1991). The production of nicotine and related pyridine alkaloids such as anabasine (45), anatabine (46), and nornicotine (47) in plant tissue, cell, and hairy root cultures has been reviewed (Verpoorte et al., 1991). 

A maj or explosion on an oil rig resulted in a fire and the deaths of 167 people. The Cullen enquiry (1990) foundahostoftechnicalandorganizational causes rooted in the culture, structure and procedures of Occidental Petroleum. The maintenance error that led to the initial leak was the result of inexperience, poor maintenance procedures, and deficient learning mechanisms. 

The use of myriad tools and technologies to construct and engineer life systems is an ancient human practice and a key factor in the evolution of the human species. Many tools and technologies are artifacts of cultures rooted in particular hiological communities. Some sustainahle traditions have heen practiced for centuries and have made important contributions to the design and maintenance of contemporary ecosystems. 

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