Epigenetics in plant tissue culture
Smulders, M.J.M. ; Klerk, G.J.M. de - \ 2011
Plant Growth Regulation 63 (2011)2. - ISSN 0167-6903 - p. 137 - 146.
dna methylation - somaclonal variation - oil palm - micropropagated plants - histone methylation - cell culture - hop plants - musa spp. - in-vitro - bushiness
Plants produced vegetatively in tissue culture may differ from the plants from which they have been derived. Two major classes of off-types occur: genetic ones and epigenetic ones. This review is about epigenetic aberrations. We discuss recent studies that have uncovered epigenetic modifications at the molecular level, viz., changes in DNA methylation and alterations of histone methylation or acetylation. Various studies have been carried out with animals, and with plant cells or tissues that have grown in tissue culture but only little work has been done with shoots generated by axillary branching. We present various molecular methods that are being used to measure epigenetic variation. In micropropagated plants mostly differences in DNA methylation have been examined. Epigenetic changes are thought to underlie various well-known tissue-culture phenomena including rejuvenation, habituation, and morphological changes such as flower abnormalities, bushiness, and tumorous outgrowths in, among others, oil palm, gerbera, Zantedeschia and rhododendron.
|Water retention capacity of tissue cultured plants
Klerk, G.J.M. de; Wijnhoven, F. - \ 2005
Propagation of ornamental plants 5 (2005)1. - ISSN 1311-9109 - p. 14 - 18.
micropropagated plants - abscisic-acid - acclimatization - cytokinins - shoots - growth
Leaves rapidly close their stomata after detachment resulting in a strong reduction of water loss. It has been reported that detached leaves of in vitro produced plants show continuous water loss indicating that they are unable to close the stomata properly and/or that their cuticle is malfunctioning. We examined the water retention capacity (WRC) of detached primary leaves of in vitro germinating seedlings of Vigna radiata (mungbean). It was shown that the poor WRC was most likely due to deterioration of the stomata by the high relative humidity in the headspace. Other features of the headspace, viz., O2, CO2 and ethylene levels, did not play a significant role. Some medium additions improved the WRC somewhat, viz., paclobutrazol and abscisic acid. Other additions such as the ethylene precursor 1-aminocyclopropane-1-carboxylic acid, the ethylene blocker silverthiosulphate and cytokinin had no or a slight negative effect.
Rooting of microcuttings: Theory and practice
Klerk, G.J.M. de - \ 2002
In Vitro Cellular and Developmental Biology. Plant 38 (2002)5. - ISSN 1054-5476 - p. 415 - 422.
micropropagated plants - pericyclic topipotency - apple microcuttings - rorippa-sylvestris - cultivated invitro - aerial organs - stem slices - fragments - acid
Poor adventitious root formation is a major obstacle in micropropagation and in conventional propagation. This paper reviews recent progress in the understanding of adventitious root formation as a developmental process focusing on the role of plant hormones and on the effect of rooting conditions on plant performance. Since the discovery of the rhizogenic effect of auxin ca. 70 yr ago, no new broadly applicable rooting treatments have been developed. Recent research, though, may lead to new rooting procedures. Application of wounding-related compounds may be effective in difficult-to-root crops. Furthermore, by adapting conditions during the propagation phase, microcuttings with an enhanced capability to root may be produced. These conditions include elongation of stems (by etiolation or double-layer culture) and repeated subculture (rejuvenation; i.e. transition from adult to juvenile). Data are presented that show that during tissue culture maturation (transition from juvenile to adult) also occurs. The conditions during the in vitro rooting treatment may have a tremendous effect on performance after transfer ex vitro. In particular, accumulation of ethylene during in vitro rooting may have a devastating effect. Addition of stress-protecting compounds during propagation or rooting in vitro may enhance the performance ex vitro