As an essential element, calcium plays a key role in plant development. The present study aimed at assessing the effects of exogenous calcium on root activity, plant growth and endogenous hormone contents in pineapple seedlings. Major experimental methods included hydroponic culture with six concentrations (0, 5, 10, 20, 40, 80 mg/L) of CaCl2 and the use of high performance liquid chromatography (HPLC) for its endogenous hormone contents. After cultivating for 48 days, the seedlings were sampled and the reduction of TTC (2,3,5-triphenyitetrazolium chloride) method was determined to assess the root activity, and the determination of endogenous hormone contents was carried out by HPLC. The results showed that the shoot fresh weight, the root activity, root length and root weight increased significantly in response to the 20 mg/L Ca2+ treatment, and all these parameters seemed to be suppressed at higher Ca2+ concentrations. The contents of endogenous hormone ZT, GA3 and IAA were evidently higher at 40 mg/L Ca2+, with ZT, GA3 and IAA reach values as high as 2.31, 31.48 and 16.57 μg/g, respectively, while the highest concentration of ABA ( 0.026 μg/g) appeared at 5 mg /L Ca2+ concentration.

We have constructed a vector pCAMBIA1300-CP:CBF3-35S:ICE1 and transformed into Arabidopsis. Results of PCR proved that the target genes had integrated into Arabidopsis genome. Transgenic Arabidopsis showed a bit slow growth, earlier flowering, but normal at other phenotype under 22°C with 8 h daily lights. In vitro low temperature stress tests showed that the transgenic lines were survival while the wild type was nearly dead. The transgenic plants also showed an increased proline content, SOD and POD activities under low temperature stress. The phenotype and physical evidence indicated that expression of CP:CBF3-35S:ICE1 under low temperature enhances the cold tolerance in transgenic plants.