Abstract:The influence factors on the dehydration tolerance of Phalaenopsis PLB (protocorm-like body) were studied, including average grain weight and water content of PLB, as well as relative humidity, time, temperature, light period, et al. The results showed that average grain weight of PLB had very significant or significant correlations with water loss rate, water content, relative conductivity and survival after dehydration, respectively. When PLB were dehydrated at high humidity, the bigger average grain weight of PLB, the greater relative conductivity reduced and the survival increased. Both water loss rate and water content of dehydrated PLB had obvious regression relations with dehydration humidity, but not significantly regression relations with dehydration time. The survival of PLB with high water content increased obviously after dehydration, but the percentage of increasing was smaller at high dehydration humidity than that at low dehydration humidity. Under dehydrated at 52% RH for 2 days, plasma membrane damage and mortality of PLB reached critical values. Although the water contents of dehydrated PLB were close, the PLB dehydrated at slow speed had lower relative conductivity and higher survival than those dehydrated at rapid speed. Survival of PLB was high when dehydrated at low temperature or in the dark. Therefore, the dehydration tolerance of Phalaenopsis PLB was extremely sensitive to its weight and water content. Besides of the dehydration relative humidity and time, the dehydration temperature and light period were the main exterior factors that influenced on the dehydration tolerance of PLB.