Search Results

You are looking at 1 - 3 of 3 items for

  • Author or Editor: Kwang-Chool Ko x
Clear All Modify Search
Author:

Fifty nine morphological characters and isozyme band patterns of glutamate oxaloacetate transminase, peroxidase, glucose phosphate isomerase from fully expanded leaves were used for taxonomic study on 51 taxa consisted of Korean native and principal cultivars of the genus Pyrus. Taxonomic relationships were analyzed by complete cluster analysis method based on Euclidean taxonomic distance of IBM PC SPSS/PC+(ver. 3.0). Among the 39 qualitative morphological characters, a great deal of variations among 51 taxa were observed in immature fruit shape, skin lusterness, hair density on pedicel, anther color, shape of leaf apex and base, hair density on leaf surface, and leaf margin. Considerable variations were found in most tested quantitative characters except in the number of petals and styles. More reliable taxonomic results could be obtained by comparing morphological characters rather than examining isozyme band patterns. Even though there were considerable differences depending upon the methods of investigation, classification of the genus Pyrus by using isozyme band patterns was proved to be a good tool for rapid taxonomic studies.

Free access

Abstract

The extractable protein in bark tissue of 1-year-old shoots of apple trees (Malus domestica Borkh. cv. Golden Delicious on Mailing (M) 26 rootstocks) declined dramatically during spring growth, while amino acids increased. Extensive degradation of protein was first visible at the silver-tip stage of growth. Prior to this period, some redistribution of nitrogenous compounds was indicated by the increase in amino acids while protein remained unchanged. Total extractable nitrogen declined during spring growth, indicating that it was mobilized to developing tissues. In vitro activity of an acid endoprotease increased rapidly upon regrowth, but its increase preceded the in vitro decline in proteins. The autolytic activity, however, did not change in the early growth stage, and protein had already declined 50% when this activity significantly increased. Electrophoretic separation of intact proteins indicated a substantial shift in relative mobility from higher to lower molecular weights as the season advanced. However, the majority of proteins showed little evidence of net breakdown during early spring growth. Two polypeptides of 38,000 and 56,000 daltons which were present up until mid-April were not detected in extracts of shoots collected in May. The 65% decline in total protein observed by May 10, however, could not be accounted for by the loss of these 2 peptides. It is thus concluded that the immediate requirement of nitrogen at the early stage of growth (up to silver-tip) is met by the transport of soluble nitrogen present in adjacent bark and that redistributed from the wood. The large requirement of nitrogen after silver-tip stage of growth is then met by massive breakdown of storage proteins.

Open Access

Abstract

The apple (Malus domestica Borkh.) cultivars Empire, McIntosh, Delicious, Triple Red Delicious, and Vermont Spur Delicious were grown on Linsmaier and Skoog (LS) medium containing 4.4 μm BA, 0.5 μm IBA, 1.3 μm GA3, 87.6 mm sucrose, and 7 g·liter−1 Difco Bacto-agar. All cultivars produced significantly more total shoots and shoots >1 cm (usable shoots) on a 16-hr compared to a 24-hr photoperiod. Removing the apical meristem significantly increased both the total and usable shoots only for ‘Triple Red Delicious’. Placing explants horizontally on the medium significantly increased the number of total and usable shoots for all cultivars except ‘McIntosh’. Internode length was significantly reduced for ‘Delicious’, ‘Triple Red Delicious’, and ‘Vermont Spur Delicious’ and increased for ‘Empire’ on 24-hr photoperiods. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA); 1H-indole-3-butanoic acid (IBA); gibberellic acid (GA3).

Open Access