The morphology of the leaves and the flowers of angiosperms exhibit remarkable diversity. One of the factors showing the greatest variability of leaf organs is the leaf index, namely, the ratio of leaf length to leaf width. In some cases, different varieties of a single species or closely related species can be distinguished by differences in leaf index. To some extent, the leaf index reflects the morphological adaptation of leaves to a particular environment. In addition, the growth of leaf organs is dependent on the extent of the expansion of leaf cells and on cell proliferation in the cellular level. The rates of the division and enlargement of leaf cells at each stage contribute to the final shape of the leaf, and play important roles throughout leaf development. Thus, the control of leaf shape is related to the control of the shape of cells and the size of cells within the leaf. The shape of flower also reflects the shape of leaf, since floral organs are thought to be a derivative of leaf organs. No good tools have been available for studies of the mechanisms that underlie such biodiversity. However, we have recently obtained some information about molecular mechanisms of leaf morphogenesis as a result of studies of leaves of the model plant, Arabidopsis thaliana. For example, the ANGUSTIFOLIA (AN) gene, a homolog of animal CtBP genes, controls leaf width. AN appears to regulate the polar elongation of leaf cells via control of the arrangement of cortical microtubules. By contrast, the ROTUNDIFOLIA3 (ROT3) gene controls leaf length via the biosynthesis of steroid(s). We provide here an overview of the biodiversity exhibited by the leaf index of angiosperms. Taken together, we can discuss on the possibility of the control of the shapes and size of plant organs by transgenic approaches with the results from basic researches. For example, transgenic plants that overexpressed a wildtype ROT3 gene had longer leaves than parent plants, without any changes in leaf width. Thus, The genes for leaf growth and development, such as ROT3 gene, should be useful tools for the biodesign of plant organs.

Bax, a mammalian pro-apoptotic member of the Bcl-2 family induces cell death when expressed in yeast. To investigate whether Bax expression can induce cell death in plant, we produced transgenic Arabidopsis plants that contained murine Bax cDNA under control of a glucocorticoid-inducible promoter. Transgenic plants treated with dexamethasone, a strong synthetic glucocorticoid, induced Bax accumulation and cell death, suggesting that some elements of cell death mechanism by Bax may be conserved among various organisms. Therefore, we developed novel yeast genetic system, and cloned several Plant Bax Inhibitors (PBIs). Here, we report the function of two PBIs in detail. PBI1 is ascorbate peroxidase (sAPX). Fluorescence method of dihydrorhodamine123 oxidation revealed that expression of Bax in yeast cells generated reactive oxygen species (ROS), and which was greatly reduced by co-expression with sAPX. These results suggest that sAPX inhibits the generation of ROS by Bax, which in turn suppresses Baxinduced cell death in yeast. PBI2 encodes nucleoside diphosphate kinase (NDPK). ROS stress strongly induces the expression of the NDPK2 gene in Arabidopsis thaliana (AtNDPK2). Transgenic plants overexpressing AtNDPK2 have lower levels of ROS than wildtype plants. Mutants lacking AtNDPK2 had higher levels of ROS than wildtype. $H_2O_2$ treatment induced the phosphorylation of two endogenous proteins whose molecular weights suggested they are AtMPK3 and AtMPK6. In the absence of $H_2O_2$ treatment, phosphorylation of these proteins was slightly elevated in plants overexpressing AtNDPK2 but markedly decreased in the AtNDPK2 deletion mutant. Yeast two-hybrid and in vitro protein pull-down assays revealed that AtNDPK2 specifically interacts with AtMPK3 and AtMPK6. Furthermore, AtNDPK2 also enhances the MSP phosphorylation activity of AtMPK3 in vitro. Finally, constitutive overexpression of AtNDPK2 in Arabidopsis plants conferred an enhanced tolerance to multiple environmental stresses that elicit ROS accumulation in situ. Thus, AtNDPK2 appears to playa novel regulatory role in $H_2O_2$-mediated MAPK signaling in plants.

Metabolic engineering for production of isoflavones in nonlegume plants could distribute the health benefits of these phytoestrogens in more widely-consumed grains. Series of investigation to check the ability of the heterologous isoflavone synthase enzyme to interact with the endogenous phenylpropanoid pathway have been conducted. Overall, results provide possibility of production of isoflavonoids in several plant tissue systems including soybean and nonlegumes. In tissue that undergoes naturally enhanced synthesis of anthocyanins, genistein production was enhanced. In a monocot cell system, introduced expression of a transcription factor regulating genes of the anthocyanin pathway was effective in conferring the ability to produce genistein in the presence of the isoflavone synthase gene. However, in this case the intermediate accumulated to high levels indicating an inefficiency in its conversion. Introduction of a third gene, chalcone reductase, provided the ability to synthesize an additional substrate of isoflavone synthase resulting in production of the isoflavone daidzein. These research efforts provide insight into requirements for metabolic engineering for isoflavone production in nonlegume dicot and monocot tissues.

Proline is known as an osmoprotectant accumulating in response to salt and dehydration stresses. An increased level of proline is achieved by either an induced synthesis or a reduced degradation of proline. In an attempt to increase salt tolerance in carrot, a P5CS gene from mothbean was introduced via an Agrobacterium-mediated transformation. The resulting carrot cells and the regenerated plants containing the transgene showed increased levels of proline compared to nontransgenics. The transgenic cell line, Pj2 showed about 6 times increased degree of tolerance determined by relative growth after a treatment in 250 mM NaCl. In facts, due to the retarded growth shown in non-saline condition, Pj2 cells grow only about 1.2 times better than nontransgenic control under salt stress condition. Taken together, it appears that a P5CS is a key enzyme in proline biosynthesis and the increased accumulation of proline by overexpression of the enzyme is enough to enhance tolerance to salt stress in carrot.

A routine system based on particle bombardment of embryogenic callus for recovery of fertile transgenic rice (Oryza sativa L.) plants was developed. Embryogenic callus was established within 2-3 months from calli derived from mature seeds of Korean rice cultivar, Nagdongbyeo. The callus was bombarded with the plasmid pRQ6 containing the $\beta$-glucuronidase gene (gusA) and hygromycin phosphotransferase gene (hph, conferring resistance to hygromycin B), both driven by CaMV 35S promoter. Placement of cells on an osmoticum-containing medium (0.2 M sorbitol and 0.2 M mannitol) 4 hrs prior to and 16 hrs after bombardment resulted in a statistically significant increase with 3.2-fold in transient expression frequency gusA. In five independent experiments, the average frequency of transformation showing GUS activities was $8.86\%$. A large number of morphologically normal, fertile transgenic rice plants were obtained. Integration of foreign gene into the genome of $R_0$ transgenic plants was confirmed by Southern blot analysis. GUS and HPT were detected in $R_1$ progeny and Mendelian segregation of these genes was observed in $R_1$ progeny.

Somatic embryogenesis was initiated from in vitro grown leaf explants of rose following an induction period of four weeks on MS basal medium supplemented with auxin and several subcultures on MS medium with cytokinin. '4th of July' showed the highest regeneration frequencies on 1 mg/L NAA followed by culture on medium with 4 mg/L zeatin. The embryogenic callus was propagated on MS medium with NAA, zeatin and $GA_3$. Germination of somatic embryos was achieved on MS medium with 1 mg/L BA. Somatic embryo derived plantlets were hardened and successfully transferred to the greenhouse.

The combination of a radiation technique with an in vitro culture system was appiled to develop submergence tolerant rice. The 3,000 $M_3$ lines with an average 80 percent of fertile grain were utilized for the selection of submergence tolerance. Salt tolerant lines were selected based on high plant height, root length and root number after submergence in plastic pots. Of the lines tested, the tolerant line (403-6) showed a dramatic difference in morphological traits under submergence compared to its original variety (Dongjinbyeo). It was suggested that genetic variations between the original variety and $M_3$-403-6 did exist. The levels of $\alpha$-amylase and alcohol dehydrogenase activities were significantly increased in the mutant line compared to its original variety. The mutant with greater tolerance showed less electrolyte leakage indicating a greater membrane integrity and better survival. Also, this line was much more resistant to a salt stress of $1.25\%$ than the original variety. The proline level of the line was significantly (p<0.01> higher than that of the original variety. The relationships between the inhibition of growth caused by stress and the physiological changes in the plant cell were discussed.

Callus and suspension cultures derived from leaf explants of Plumbago rosea were established on Murashige and Skoog's medium containing 1 mg/L IAA, 0.5 mg/L NAA and 0.3 mg/L BAP. Callus cultures were tested for their growth and accumulation of plumbagin, a naphthoquinone and was identified by $^1H$ NMR and electron ionization mass spectroscopy. While auxins (not 2,4-D) influenced growth and plumbagin accumulation, cytokinins did not influence them much. Increasing concentrations of IAA in presence of NAA and BAP increased plumbagin in suspensions only up to 1 mg/L. Growth of callus was optimum (8.3 g DCW/I) at a hormonal combination of 1.5 mg/L IAA, 0.5 mg/L NAA and 0.3 mg/L BAP, but high plumbagin accumulation (4.9 mg/g DCW) was recorded at 1.0 mg/L IAA plus 0.3 mg/L BAP. Since instability in growth and secondary metabolite accumulation was noticed, several cell lines/clumps of callus were screened for plumbagin accumulation by visual and analytical methods. Biomass and accumulation of plumbagin showed a negative correlation in several cell lines. But one cell line showed stability both in terms of biomass and plumbagin accumulation over a period of 6 months.

This paper reported the establishment of mass production system of adventitious roots of Eleutherococcus sessiliflorus through the shake flask and bio-reactor culture. Induction of adventitious roots was started from the explants of germinated somatic embryos on half-strength Murashing and Skoog (MS) solid medium. The frequency of adventitious root formation was better in the explants comprising the basal hypocotyl parts than root explants alone. Among the different auxins tested (NAA, IBA and IAA), frequency of adventitious root induction was highest on medium with 0.5 mg/L NAA, and produced $16.3\pm1.9$ roots per explant. In shake-flask culture, deletion of $NH_4NO_3$ of MS medium was effective for induction of adventitious root compared with both full and half-strength MS media. Fresh weight increase of induced adventitious roots was performed well in medium with 0.5 mg/L IBA. When adventitious roots produced in shake-flask culture were transferred to 10-liter bioreactor, 5.5 times of fresh weight increase was gained after one month of culture. HPLC analysis revealed that the amount of eleutheroside E and E1 was higher in in vitro cultured adventitious roots than the 3 year-old field cultivated root barks of Eleutherococcus sessiliflorus. The content of eltutheroside B was much lower in adventitious roots than that of field cultivated one.