The induction of tuberous roots of cassava in vitro is functional in MS medium containing 0.54 mM NAA, 0.44 mM BA and 3%-7% sucrose; meanwhile, the saccharide accumulation in the induced tuberous roots was increased with the sucrose content addition from 3%-7% in the inducible medium. Thus, the sucrose is an important factor for tuberous root induction in Cassava in vitro. The experimental results showed that the appropriate concentration of sucrose played a key role on the tuberous root induction in Cassava in vitro.

Soil moisture content and soil porosity were measured in banana plantation under three tillage practices, including deep-tillage (DT), no-tillage (NT), and no-tillage plus straw cover (NTSC). In the experiments, the top layer soil was separated into three depth including 0~15 cm, 15~30 cm and 30 ~ 45 cm. The soil sampling were performed at four plant growth periods, including the stage of banana seedling (SBS), metaphase of banana (MB), the stage of pregnancy (SP) and pumping stage (PS). The results showed that: Among three depth of top layers, soil moisture content in 0~15 cm at four plant growth periods was lower than that in other two depth by three tillage practices. In 0~15 cm top layer soil, all the soil moisture at four plant periods by NTSC practice were highest. And all the soil moisture in soil treated by three tillage practices were increased with the plant growth. The soil porosity in this layer at SBS and MB stages by DT practice was significantly higher than that by NT and NTSC practices. In 15~30 cm layer soil, the soil moisture content and soil porosity at SBS stage was highest in the soil treated by DT practice compared to the that in soil treated by other two tillage practices. In 30~45 cm layer, the soil porosity at SBS stage by DT and NTSC practices were significantly lower than that by NT practice. At MB stage by DT practice it was significantly higher than that by other practices.

In order to study the inducement pattern and regulating mechanism of MeCWINV3 in Cassava. An 1160 bp promoter region upstream of the MeCWINV3 gene (GenBank Accession No. KC905170) was isolated from Cassava (Manihot esculenta) genomic DNA using PCR methods. Sequence analysis found that it contains typical TATA box and CAAT box, and several cis-acting elements that related plant stress responses, such as ABRE, ARFAT, GAREAT, MYB and MYC transcription factors. Furthermore, transient expression in transgenic tobacco was analyzed by inserting upstream of GUS gene in expressing vector. The results showed that GUS was mainly expressed in tobacco veins. This will be the basis for further investigating the function of the MeCWINV3 gene promoter.

Vacuolar invertases play a vital role in the progress of cassava tuber roots starch accumulation. In order to study the regulating mechanism of cassava vacuolar invertases, the promoter of cassava vacuolar invertase 2 (MeVINV2) was isolated using the PCR amplification approach, starting with a part of coding sequences. Sequencing result showed that 47 bp MeVINV2 gene CDS sequence and 1242 bp potential promoter sequence was obtained. PlantCARE analysis revealed that the MeVINV2 gene promoter contains typical eukaryotic elements CAAT box and TATA box, and also several light-responsive elements and stress-responsive elements. These cis-acting regulatory elements might be associated to the vacuolar invertase gene function of cassava starch accumulation and biological stress defense.

A full-length sequence coding for a betaine aldehyde dehydrogenase gene from S. portulacastrum was cloned into expression vector pGEX-4T-1, and named pGEX-4T-SpBADH. The GST-SpBADH fusion protein was expressed and the expression conditions were optimized. Through the research on optimization of expression the concentration of IPTG, concentration of bacterium, induction time and temperature and so on, the results showed, the expression of GST-SpBADH increased accompany with the induction time. The expression level of GST-SpBADH fusion protein reached the highest for 5 h cultured and for OD600 is about 0.6 at 37°C, 0.2 mmol/L IPTG can effectively induce the expression of GST-SpBADH in Escherichia coli expression system.