Studies on the environmental control for the mass propagation of the tissue cultured transplants by direct ex-virto rooting method

本研究探讨了“直接离体生根法”组培苗大批量繁殖的环境控制。在直接离体生根法中，在光自养条件下，外植体/苗在环境控制单元中同时实现了苗的伸长、生根和驯化。实验结果如下：1)研究了光合光子通量密度（PPFD）和培养液浓度对草莓幼苗生长的影响。将外植体直接插入岩棉塞中，用不同浓度的培养液在环境控制单元内水培培养。培养液浓度对植株生长的影响在高PPFD条件下明显大于低PPFD条件下。2)在一定的高相对湿度条件下，风速对外植体/植株的蒸腾速率有影响。为了降低植株的死亡率，提高植株的生长速度，控制植株附近的风速似乎与控制湿度同样重要。3)讨论了抑制植株死亡的条件，并获得了各种信息。4)用该方法考察了外植体重量与种植后生长的关系。外植体质量相对较低的处理可提高相对生长率（RGR）。与传统方法相比，该方法的培养周期缩短，移栽量小。

In this study, the environmental control for the mass propagation of the tissue culture plantlets by 'direct ex-vitro rooting method' was discussed. In the direct ex-vitro rooting method, the shoot elongation, rooting, and acclimatization of the explants/plantlets are simultaneously achieved in the environmental control unit under the photoautotrophic condition. The following results were taken from the experiments.1) The effects of the photosynthetic photon flux density (PPFD) and concentration oi culture solution on the growth of strawberry plantlets were examined. The explants of micropropagated shoots were directly inserted into rockwool plugs and cultured inside the environmental control unit by hydroponics using a culture solution at different concentrations. The effect of the concentration of culture solution on the growth of plantlets was obvious in high PPFD than that in low PPFD.2) The transpiration rate of the explants/plantlets was changed by wind speed at a certain high relative humidity. In order to reduce the death rate and to increase the growth rate of the plantlets, the control of the wind speed near plantlets seems to be as important as the control of humidity.3) The conditions to repress the death of plantlets were discussed and the various informations were obtained.4) The relationship between the weight of explants and the growth after planting was examined in this method. The relative growth rate (RGR) was promoted in the treatment of relatively low weight of the explants. It seems that the culture period will be shortened and small transplant will be produced in this method than in the conventional method.