Development of leaf area and leaf number of micropropagated potato plants
Keywords:<i>in vitro</i> plantlet, leaf area, leaf number, leaf appearance, leaf expansion, logistic growth, <i>Solanum tuberosum</i> L., temperature, transplant chock
AbstractAboveground leaf area and leaf number development of in vitro produced potato plantlets was studied over three growth phases. In vitro plantlets were produced at 17 or 23°C (normalisation phase, 3 weeks), planted in soil at 18/12 or 26/20°C (transplant production phase, 2 weeks), and later transplanted at 18/12 or 26/20°C (tuber production phase, 6 weeks). Boosts in leaf area increase and leaf appearance occurred in the first days after planting to soil. A shock in leaf area increase occurred after the later transplanting. Both for plant averages and most individual plants, leaf area increase in all growth phases was best described by logistic curves, indicating growth limitations occurred in all phases. These limitations were least severe during the relatively short transplant production phase. Higher temperatures did not significantly increase leaf area during normalisation, increased leaf area during transplant production, and first increased but later reduced leaf area during tuber production. Higher temperatures increased leaf number in all phases. After-effects of normalisation temperature occurred during transplant production but no longer during tuber production. Aftereffects of transplant production temperature occurred during tuber production. After-effects were direct (affecting plants at the beginning of the next phase) or appeared later.