• Korean Journal of Plant Tissue Culture
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• v.24 no.6
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• pp.329-334
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• 1997

Adventitious organs (shoots and roots) from mature leaves of Populus deltoides (Eastern cottonwood) clones were induced on WPM (Woody Plant Medium) containing fructose as a carborn source and different combinations of either BA (Benzyl aminopurin) or TDZ (Thidiazuron) with NAA (Naphthaleneacetic acid). The morphologies of adventitious shoots were different depending on the kinds of growth regulators and the length of shoots induced on the medium containing BA were generally longer than that of TDZ. BA 0.5 mg/L and TDZ 0.01 mg/L combined with either 0.05 or 0.1 mg/L NAA showed the highest values in the frequency of regeneration (63% to 100%) the number of shoots per explant and in the organogenic sites per explant among tested three clones (A, B and C). Although there was a minor clonal difference in the development of adventitious shoots from leaf segments, their responses to growth regulators were very similar.

• Journal of Life Science
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• v.7 no.2
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• pp.134-141
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• 1997

We have investigated several factors influencing adventitious shoot induction from the Populus deltodies bartr. leaf segments. To obtain in vitro materials, at first, stem segments from ex vivro were tested for axillary bud breaking on the five macronutrients levels of two differenr media. WPM was better both in bud breaking and leaf expansion than MS medium. The amount of NH$_{4}$NO$_{3}$ added in the medium did not seem to affect axillary bud breaking, significantly and subsequent shoot elongation from the stem segments of P. deltodies. However, other components in WPM might have played important roles in axillary bud breaking and shoot elongation. Regenerability from three sections (the distal, the middle and the base) of leaves cultured on WPM supplemented with TDZ and NAA combinations appeared to be different; middle and basal sections of leaves produced more organogenic sites than those of top section on WPM and those sesctions produced the highest ogranogenic sites on the same medium supplemented with 0.01 mg/l TDZ and 0.02mg.l NAA. Among 3 carbon sources tested for adventitious shoot elongation, fructose seemed to be stimulating the elongation of adventitious shoots. Sucrose and glucose added in the medium resulted in the necrosis which caused dying of adventitious shoots, eventually.

• Journal of Plant Biotechnology
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• v.2 no.1
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• pp.43-49
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• 2000

An efficient and reliable Agrobacterium transformation procedure based on TDZ (thidiazuron)-induced organogenesis was established and applied to six Brazilian eggp1ant varieties. Optimum transgenic plants recovery was achieved upon the study of the following parameters affecting transformation efficiency, using F-100 variety as a model: i) explant source; ii) pre-culture period; iii) physical state of the pre-culture medium and iv) coculture conditions. The highest frequency of kanamycin-resistant calli derived from leaf explants (5%) was obtained without a pre-culture period and co-cultivation for 24 h in liquid medium followed by five days on solid RM (regeneration medium). For cotyledon explants, best results were achieved upon a pre-culture of 24 h in liquid RM and a co-cultivation period of 24 h in liquid RM followed by three days in solid RM, resulting in a transformation Sequency of 22.7%. Kanamycin-resistant organogenic calli were also obtained from cultivars Emb, Preta Comprida, Round nose Shaded, Campineira and Florida Market. The expression pattern of an epidermis-specific promoter was studied using transformants expressing a chimaeric construct comprised by the promoter Atgrp-5 transcriptionally fused to the coding region of the gus gene. The expression pattern was similar to that previously observed in tobacco and Arabidopsis thaliana, with preferential expression at the epidermis and the stem phloem. These results support the idea that the Atgrp-5 promoter can be used to drive defense genes in these tissues, which are sites of pathogen interaction and spread, in programs for the genetic improvement of eggplant.