Miscanthus sinensis (Poaceae) is a typical perennial giant grass of East Asia. Due to its high photosynthetic efficiency, low input requirements, and high biomass production, M. sinensis shows outstanding potential as a biofuel feedstock. However, the lack of an efficient tissue culture system may limit its utilization potential. Different explants of M. sinensis were evaluated to develop an efficient tissue culture system. Shoot apices from in vitro-germinated seedling explants were tested for adventitious bud proliferation. The highest level of proliferation (multiplication coefficient 6.69) was obtained when shoot apices were cultured on Murashige and Skoog (MS) medium supplemented with 1.0 mg L −1 6-benzyladenine (BA), 2.0 mg L −1 kinetin, 0.05 mg L −1 α-naphthalene acetic acid (NAA), 3% sucrose, and 0.8% agar. The highest rooting percentage (95.4%) was obtained when adventitious buds were cultured on half-strength MS medium supplemented with 0.2 mg L −1 NAA, 3% sucrose, and 0.8% agar. Significant differences were found in the formation of embryogenic callus among different explant types. The embryogenic callus derived from epicotyls had the highest regeneration capacity when cultured on a medium supplemented with 2.0 mg L −1 2,4-dichlorophenoxyacetic acid, 0.5 mg L −1 BA, and 0.1 mg L −1 thiamine. Under these conditions, the callus induction percentage was 82%.

In order to provide parent material for small-type triploid watermelon, this study has been carried out to induce high-quality tetraploid watermelon. We induced tetraploid plants of watermelon by treating the growing points of seedlings of a small-type yellow flesh diploid watermelon with 40, 60 and 100ml/L Oryzalin for different treating time. The autotetraploid plants were selected and identified basing on morphology, determination of the number of chloroplasts in stomatal guard cells, flow cytometry analysis and hybridization. Then we observed a stable autotetraploid material. The results showed that tetraploid watermelons could be obtained under different treatments. The most effective way was extirpating the interior leaves at the 8th day after sowing, then treating the growing points of seedlings with 100mg/L Oryzalin for 6d. The treated seedlings could all survive and the induction frequency of the tetraploid watermelon was 33.33%.

Carotenoids, the naturally occurring isoprenoids form essential components of photosynthetic antenna and reaction centre complexes. Thus they play a significant role in absorption, dissipation and transfer of light energy for the process of photosynthesis. The expression of salt stress on carotenoid gene in watermelon leaves were studied. For that watermelon plants were subjected to different concentration of salt water. Morphological characters such as plant height, no. of fruits per plant,chlorophyll content and expression of four major carotenoid pathway genes such as phytoene synthase(PSY), phytoene desaturase(PDS), zeta carotene desaturase(ZDS) and lycopene beta cyclase(LCY-β) were analysed. The quantitative expression analysis using real time PCR has shown a decrease in the expression of all the studied genes as the salt concentration increased. Among the different concentrations of NaCl used for the experiment, it was seen that 200 mM was most detrimental for the carotenoid gene expression.Lycopene beta cyclase, the enzyme that converts lycopene to beta carotene was seen to be highly affected compared to other genes studied showing a 1.87 fold inhibition in its expression at 200 mM NaCl.

A new method for producing seedless watermelon seedlings was studied in this paper. Grafting branches breeding (GBB) and grafting seedling breeding (GSB) of seedless watermelon (Citrullus lanatus (Thunb.) Matsum and Nakai) cultivar Mi Tong was grafted onto No.1 of E-zhen, commercial hybrids. Seed breeding (SB) self-plants were used as control. The effect of different methods on watermelon fruit yield and quality was tested. The results showed that fruit yield was positively influenced by GBB when compared with the control. Detrimental effects were not determinated on fruit qualities such as fruit index, fruit weight and sugars on grafted plants. Moreover, GBB reduced the cost of producing seedless watermelon seedlings. Therefore, the grafting technique of using branches for scion was feasible, simple and efficient in the progress of seedless watermelon development.

Plant growth is impressed by biotic and abiotic stress inversely. There are many reports about proteins change level in salinity stress. Leaves fill up more soluble sugar of glucose, fructose and proline with treatment of salicylic acid. In this study, Citrullus lanatus seeds planted in pots containing perlite were put in a growth chamber under controlled conditions of 30 ±2 °Cand 14 ±2 °Ctemperature, 14h lightness and 10h darkness; NaCl concentration of 0,4,8,12 ds/m and salicylic acid concentration of 0,1,2,4 mM were used in the form of factorial experiment in a complete randomized design (CRD). The results demonstrated that increasing of proline and sugars due to osmotic slope in plants lead to increasing of tolerance against dehydrations of leave content and acceleration of plant developments in stress conditions.