The Study Of Water Permeability Of Plant Under The Urban Environment

The plant cuticle is a key obstacle to prevent water loss and contaminants into mesophyll. We researched the leaf cuticle water permeability of 3 kinds green plants under the urban environment, such as Ligustrum lucidum Ait, Euonymus japonicus and Photinia serrulata Lindl. The astomatous cuticular membranes were isolated by oxalic acid / ammonium oxalate immersing method, and the water permeability was measured by micro- transpiration chamber. At same time, the possible effects of urban air pollution matter to water permeability of leaf cuticle were analyzed.(1)The four methods that was used to isolate the plant astomatous cuticular membranes was compared, which were oxalic acid / ammonium oxalate solution, zinc chloride-hydrochloric acid solution, cellulase / pectinase solution and chromium trioxide solution. The oxalic acid / ammonium oxalate solution isolated method is the better for comprehensive detached integrity and time-consuming for that plant we need research(2) The water permeability coefficient of upper epidermis of Euonymus japonicus were 6.00×10-9 m/s to 2.03×10-8 m/s, and the water permeability coefficient of lower epidermis were 1.50×10-8 m/s to 6.73×10-8 m/s. For another tree Photinia serrulata Lindl, the water permeability coefficient of upper epidermis were 7.48×10-9 m/s to 3.60×10-8 m/s, and the lower epidermis were 3.56×10-8 m/s to 6.62×10-8 m/s. The water permeability coefficient of upper epidermis of all 2 kinds plant were higher than that of lower epidermis, the reason maybe the existing of stoma in lower epidermis(3) The water permeability coefficient of astomatous cuticular membranes were5.81 × 10-9 m/s(August) to 1.50 × 10-8 m/s(July), 1.38 × 10-8 m/s(April) to 2.50 × 10-8 m/s(October), and 8.27 × 10-9 m/s(September) to 2.08 × 10-8 m/s(May), respectively for Ligustrum lucidum Ait, Euonymus japonicas and Photinia serrulata Lindl. The permeability coefficient of Ligustrum lucidum Ait in April were the highest and the permeability coefficient of June were lower than othere monthes, and for Photinia serrulata Lindl in May were the highest and the lowest in October. But for the Euonymus japonicus, the highest permeability coefficient appeared in October and the lowest in September.(4)The water permeability coefficient of Euonymus japonicus was significantly positively related to highest temperature, and the correlation coefficient is 0.840. It also has significant positive correlation with the lowest temperature, and the correlation coefficient is 0.768. Among the three plants, Euonymus japonicus is more sensitive to climate temperature. The frequency of appearing correlations between the membrane permeability coefficient and air pollutant concentrations, the Euonymus japonicus was the highest, this suggested that among the three kinds of plant was more suitable for indicator plant for air pollution.