The purpose of this study was to investigate the effects of root zone temperatures (RZT) on the germination of bell peppers and tomatoes. Bell peppers and tomatoes had the highest germination rates (85% and 90%, respectively) at 25oC air temperature. Besides, the first germination of bell peppers was shifted by one day ahead. Bell peppers had the highest germination rate of 72,100, and 100%, respectively, when the RZT was adjusted to 30oC at airtemperature of 20, 25, and 30oC, and when the air temperature was adjusted to 35oC, the germination rate was the highest (70%) when the RZT was 15oC. Tomatoes had the highest germination rate at 20oC of the RZT at all atmospheric temperatures. A local cooling and heating system was established to improve the germination rate by controlling the RZT during the low and high temperature period. The optimum RZT for seedlings during the low and high temperature period was investigated.

A protocol for the production of transgenic Panax ginseng C.A. Meyer was established via Agrobacterium tumefaciens-mediated genetic transformation of direct somatic embryos. A number of conditions related to the co-cultivation were tested with respect to maximizing transformation efficiency. The results showed that pH of the co-cultivation medium (5.7), the bacterial growth phase (optical density; OD600 = 0.8), co-cultivation period (3 days), and acetosyringone concentration (100 μM) had positive effects on transformation. Selected plantlets were cultured on the medium at an elevated hygromycin level(30 mg/l). Integration of the transgenes into the P. ginseng nuclear genome was confirmed by PCR analysis using hpt primers and by Southern hybridization using hpt-specific probe. The transgenic plantlets were obtained after 3-month cultivation and did not show any detectable variation in morphology or growth characteristics compared to wild-type plants.

The cost of conventional cultivation of ginseng (Panax ginseng C.A. Meyer) is very expensive, because shadow condition should be maintained during cultivation periods owing to inherently weak plant for high-temperature. Therefore, application of plant biotechnology may be possible to overcome these difficulties caused by conventional breeding of ginseng. Transgenic plants were produced via Agrobacterium tumefaciens Gv3101, both carrying the binary plasmid pBI121 mLPISO with nptII and Iso (isoprene synthase) gene. Integration of the transgenes into the P. ginseng nuclear genome was confirmed by PCR analysis using nptII primers and Iso primers. RT-PCR result also demonstrated the foreign isoprene synthase gene in three transgenic plant lines (T1, T3, and T5) which was expressed at the transcriptional level. When whole plants of transgenic ginseng were exposed to high temperature at 46℃ for 1 h, a non-transformed plant was wilted from heat shock, whereas a transgenic plant appeared to remain healthy. We suggest that the introduction of exogenous isoprene synthase is considered as alternative methods far generating thermotolerance ginseng.