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.

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.

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