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Abstract
Shoots tips from in vitro cultures of Heuchera sanguinea Engelm. ‘Rosamundi’ were cultured on a modified woody plant medium containing one of 3 cytokinins (BA, 2iP, kinetin) or cytokinin plus NAA. BA and kinetin were the most effective stimulators of axillary shoot growth. Maximum shoot production (≥1 mm) occurred with 2, 4, 8, and 16 μm BA, or 16, 32, and 64 μm kinetin. The addition of NAA had no effect or reduced the number of shoots produced. Because of the rosette growth pattern, rooting of the resultant shoots was best accomplished by placing whole cultures in a soilless medium under high humidity and later dividing the rooted shoot masses. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA); N-(3-methyl-2-butenyl)-1H-purin-6-amine (2iP); N-(2-furanylmethyl)-1H-purin-6-amine (kinetin); and 1-naphthaleneacetic acid (NAA).
Abstract
Single node explants from in vitro derived shoots of Vinca minor L. ‘Bowlesii’ were cultured on modified woody plant medium (WPM). A more effective promoter of axillary shoot proliferation was 6-benzylamino purine (BA) than 6-furfurylamino purine (kinetin) or 6-(γ,γ-dimethylallylamino) purine (2iP). Maximum production of shoots 5 mm and longer occurred in a medium containing 64 μm BA and 0.1 μm α naphthaleneacetic acid (NAA), whereas 64 μm BA and 1.0 μm NAA produced the most shoots 10 mm and longer. Proliferated shoots were rooted and established in a soilless medium under high humidity.
Abstract
Shoot tips from in vitro cultures of Veronica spicata L. ‘Red Fox’ were grown on modified Woody Plant Medium containing one of 3 cytokinins or cytokinin plus NAA. Of the 3 cytokinins tested (BA, kinetin, and 2iP), BA was the most effective stimulator of axillary shoot growth. The greatest number of shoots greater than or equal to 5 mm in length was produced on medium containing 8 μM BA plus 0.01 μM NAA, whereas medium containing 2 μM BA plus 0.01 μM NAA produced the greatest number of shoots greater than or equal to 10 mm. Shoots were rooted and established at an 80% rate in a soilless medium under high humidity. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA); N-(3-methyl-2-butenyl)-1H-purin-6-amine (2iP); N-(2-furanylmethyl)-1H-purin-6-amine (kinetin); 1-naphthaleneacetic acid (NAA).
Abstract
Changes in the levels of putative free and conjugated indole-3-acetic acid (IAA) were examined by high performance liquid chromatography (HPLC) during the first 96 hr of adventitious root formation in mung bean [Vigna radiata (L.) R. Wilcz. ‘Berken’] stem cuttings. The putative IAA was characterized as biologically and chemically similar to IAA; ester- and amide-conjugated IAA also were found. Amide-conjugated IAA was an order of magnitude more abundant than either free or ester-conjugated IAA, both of which were present at low levels. In duplicate experiments, the relative levels of free and conjugated IAA in the rooting region fluctuated similarly during root formation, although some differences in timing and magnitude were observed.
Abstract
Adventitious roots in mung bean [Vigna radiata (L.) R. Wilcz. cv. Berken] cuttings develop from specific “rooting-zone parenchyma” (R-ZP) cells. Microautoradiography was used to determine the timing of thymidine and uridine incorporation into the R-ZP cells, prior to the first cell division, in the presence or absence of naphthaleneacetic acid (NAA). Since 6-3H-thymidine incorporation reached a maximum between 11 and 14 hours, we suggest that the R-ZP cells were in the G1 phase when the cuttings were taken. Tritiated uridine was incorporated into the RNA of the R-ZP cells 2 hours after the cuttings were placed in the labeled solution. DNA synthesis and cell division of the R-ZP cells occurred along the entire length of the hypocotyl (basal, middle, and top segments), but these initial events were not sufficient to result in the subsequent formation of adventitious roots. NAA promoted adventitious root formation in the cuttings but it had no apparent effect on nucleic acid labeling nor initial cell division of the R-ZP cells. The initial division of the R-ZP cells appears to be a wounding response and occurs in the presence or absence of exogenous auxin.