Xuzhou City, 8 Species Of Evergreen Broad-leaved Species Of Cold Hardiness

In this study, morphological and physiological characterics of eight evergreen broad-leaftrees such as Ligustrum lucidum, Trachycarpus fortunei, Photinia serrulata, Osmanthusfragrans, Magnolia grandiflora, Eriobotrya japonica, Cinnamomum camphora, Myrica rubrawere researched under the natural low temperatures during the overwintering in the city ofXuzhou. In addition, conductivities, soluble sugar, malondialdehyde, superoxide dismutasewere measured through the treatment of low temperature gradient (-3℃—-21℃) so as tostudy therir abilities of overwintering in Xuzhou. And the main conclusions were as follows:1. The overwintering abilities of eihgt evergreen broad-leaved tree species wereestimated on their morphology. Magnolia grandiflora, Eriobotrya japonica were the mostresistant to cold, while Myrica rubra was the least, and others were in the medium.2.The semi-lethal temperature of these were analysed through the measurement of therelative conductivity and the calculation combining with the Logistic equation and the resultsof Eriobotrya japonica, Magnolia grandiflora, Osmanthus fragrans, Trachycarpus fortunei,Photinia serrulata, Cinnamomum camphora, Ligustrum lucidum, Myrica rubra were-16.59℃,-13.30℃,-12.77℃,-12.59℃,-12.06℃,-11.16℃,-10.54℃,-6.14℃in correspondence.3.The content of soluble sugar content in the eight evergreen broad-leaved speciesshowed the tendency in the increase in the amount with the decrease in temperature whilediffered in the change range. Magnolia grandiflora was the highest in the relative increaseamplitude which was followed by Osmanthus fragrans, Eriobotrya japonica, Cinnamomumcamphora, Trachycarpus fortunei, Photinia serrulata, Ligustrum lucidum and Myrica rubra.It reflects that soluble sugar content in leaves of the anti-cold tree species is relativelyincreased considerably.4. The relative increase amplitude in MDA content under low temperature treatmentwere arranged with the order Myrica rubra569.67in percentage, Ligustrum lucidum387.37,Cinnamomum camphora318.04,Trachycarpus fortunei159.17,Photinia serrulata147.74,Osmanthus fragrans105.10,Magnolia grandiflora79.70, Eriobotrya japonica71.32in percentage.Results indicated that MDA content in leaves of tree species of weak coldhardiness is increased considerably as the temperature decreasing.5. The SOD activity increased initially while decreased later in low temperature. In theearly stage of the decrease in temperature, SOD activity raised in order to adapt theenvironment while reduced at the lethal temperature. Considering this, the SOD activity ofEriobotrya japonica was highest with Magnolia grandiflora, Osmanthus fragrans, Photinia serrulata, Trachycarpus fortunei, Cinnamomum camphora, Ligustrum lucidum and Myricarubra followed.6. The thickness of the order of the eight species in the leaves were sequenced asMagnolia grandiflora, Photinia serrulata, Eriobotrya japonica, Ligustrum lucidum,Osmanthus fragrans, Myrica rubra, Trachycarpus fortunei, Cinnamomum camphora. And,the sequence in the value of the proportion between thickness in palisade tissue and thicknessof spongy tissue was Eriobotrya japonica, Magnolia grandiflora, Osmanthus fragrans,Photinia serrulata, Cinnamomum camphora, Ligustrum lucidum and Myrica rubra.7. The features in cold resistance were evaluated comprehensively using the method offuzzy subordinate degree from the most to the least were Eriobotrya japonica,Magnoliagrandiflora, Photinia serrulata, Osmanthus fragrans, Cinnamomum camphora, Trachycarpusfortunei, Ligustrum lucidum and Myrica rubra. The abilities in actuality coulbe be reflected inthe evaluation results, so this method could be feasible.