Submitted to: Plant Cell Tissue and Organ Culture
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/6/2009
Publication Date: 9/16/2009
Publication URL: www.springerlink.com/content/3hp822756700267l/fulltext.pdf
Citation: Sun, Q., Sun, H., Bell, R.L., Xin, L. 2009. Effect of polyvinyl alcohol on in vitro rooting capacity of shoots in pear clones (Pyrus communis L.) of different ploidy. Plant Cell Tissue And Organ Culture. 99:299-304. Interpretive Summary: Micropropagation or plant tissue culture is a method to rapidly produce plants that is based upon growing small shoots in glass or plastic containers on an artificial medium that contains nutrients and plant hormones that stimulate shoot multiplication, a process that is called in vitro shoot proliferation. The resulting shoots must then be stimulated to form roots before they can be removed from the containers and grown in greenhouses or the field. The subjects of the present study are pear plants with multiple sets of chromosome, termed polyploids. Polyploid plants may offer advantages, such as larger fruit size, over the original plants with the normal two sets of chromosome, termed diploids. The plants in this study were artificially produced and micropropagated in vitro and contain either three sets (triploids), four sets (tetraploids), or a mixture of tissues with different numbers of sets (mixploids). Utilitization and further study require rooting. A compound, polyvinyl alcohol (PVA), has been shown to improve rooting in other plants and was tested for its effect on rooting of the polyploidy plants. The addition of PVA to the artificial rooting medium improved rooting of the diploid, triploid, and tetraploid plants but had little or no stimulating effect on the mixploid plants. PVA stimulation of rooting will help to produce whole plants for further study of tree and fruit characteristics.
Technical Abstract: Poor adventitious root formation is a major obstacle in micropropagation. In this study, intense efforts have been made for improvement of rooting procedures for triploid, tetraploid, and mixploid clones of the pear cultivar, 'Fertility', obtained by in vitro colchicine treatment. An efficient rooting procedure has been developed for the pear clones of different ploidy by adding polyvinyl alcohol (PVA) to the rooting medium. PVA significantly improved rooting percentage and root number per plantlet for diploid, triploid, and tetraploid clones. However, PVA had little or no effect on rooting capacity of mixploid clones. The efficiency of in vitro rooting in diploid, triploid, tetraploid, and mixploid is highly genotype-dependent. In general, diploid was the highest, followed by triploid and tetraploid. Mixploid was the lowest.