Flooding responses of eight tree species introduced from America | 8种美国引进树种苗期水涝胁迫的响应差异

Chinese. 以我国乡土树种枫香、蓝果树为对照,研究水紫树、沼地紫树、美国枫香不同种源、纳塔栎、洋白蜡等8个美国引进树种（包括种源）在人工模拟水涝胁迫下的死亡率、最终成活率、地径生长量以及水涝21 d和49 d时叶片的叶绿素含量和叶片受害情况等。结果表明,水涝49 d以后,我国乡土树种蓝果树死亡率较高,其他大部分树种在水涝胁迫下能够存活,树种之间死亡率没有显著差异（P〉0.05）;研究还发现,水涝胁迫抑制蓝果树、河桦、美国枫香LA种源和纳塔栎的地径生长,而促进其他树种的地径生长;对叶绿素含量的分析表明,水涝对叶绿素a/b比值和总叶绿素含量的影响由于不同树种和不同水涝时期而不同,随着水涝时间的延长,对水涝适应性较强的树种（如水紫树和沼地紫树）叶片叶绿素a/b比值由最初的下降转为升高;根据地径生长率和叶绿素a/b比值计算的耐受系数的分析,水紫树、沼地紫树、纳塔栎、美国枫香SC种源和中国枫香宜兴种源对水涝胁迫的耐受性较好。[著者文摘]

English. The present study demonstrates the differences of growth reponses and tolerance to flood stress among 8 exotic tree species （ including provenances） using 2 native tree species as control. We studied the mortality, the survival rate,collar diameter growth and foliar symptoms of all tested trees and measured the content of chlorophyll in leaves respectively after 21 d and 42 d of flooding treatment. The results showed nearly all the trees tested in this experiment survived during the whole period of flooding except the native tree species Nyssa sinensis which showed a relatively high mortality after 49 days of flooding treatment, and there is no significant difference among the mortality of other species （P 〉 0. 05）. We also found flood stress inhibited the net growth rate of collar diameter of Nyssa sinensis,Betula nigra, LA provenance for Liquidambar styraciflua and Quercus nuttallii, and promoted the net growth rates of collar diameter of the other trees to different extent. The total chlorophyll content and the ratio between chlorophyll a and chlorophyll b of 11 trees were either inhibited or elevated during the whole period of flood. Some of the trees exihibited more powerful tolerant to flooding with the elevation in chlorophyll content at the late stage of flooding. We finally concluded that there are significant differences among the 11 trees according to the tolerance index of net growth rates of collar diameter and the ratio between chlorophyll a and chlorophyll b （ P 〈 0. 05 ）, and suggested Yixing Nyssa sylvatica v. biflora,Nyssa aquatica,Quercus nuttallii, LA provenance for Liquidambar styraciflua and provenance for Liquidamba formosan Hance as the most suitable trees for wetlands.